Sunday, December 28, 2008

Ursid Bolide

The Ursids meteor shower is usually a minor shower with ZHR < 10 which has produced outburst in 1945, 1982 and 1986. As this is a very poorly-observed shower, other similar events could easily have been missed due to poor weather or too few observers active.

It was discovered during the outburst of 1945 even if a first mention of this shower is found on a 1914 paper by Denning. 8P/Tuttle is the parent comet.

The 2008 Ursids peak was expected on 22 December. Thanks to good weather, our meteorcam captured many Ursids on the morning of 22 December.

Below you can see the photo and the video of the brightest one:










References

- Meteor Showers and their Parent Comets by P. Jenniskens
- Ursids by Jenniskens et al. (WGN 35:6 2007)

Monday, December 15, 2008

Meteor Camera and one nice fireball

A couple of months ago we started to work on an automatic meteor detection system to be installed in Castellammare di Stabia, Italy. A special camera is linked to a software for the automatic detection of video meteors. More details about the setup in a next post.

On the very first evening, our meteorcam recorded this nice -4 magnitude fireball. The fireball appeared over Castellammare di Stabia at 21:51 local time of 07 December 2008 :

Sunday, November 16, 2008

(3200) Phaethon

Phaethon is an Apollo type asteroid with many peculiarities. It has been discovered in 1983 by Green and Davies while searching images of IRAS satellite. So it is the first asteroid to be discovered by a spacecraft. Moreover the orbit is unusually short (P 1.59 yr) with a small perihelion distance of q= 0.141 AU.

In 1983, Fred Whipple identified Phaethon like the parent of Geminid meteor stream. But it has never displayed unambiguous cometary activity. Some people hold on to the opinion that Phaethon is a comet (or extinct comet), while other thinks that it is more an asteroid or the likely product of a breakup.

In a recent article has been suggested that planet-crossing object 2005 UD is dynamically similar to Phaethon and so that:

"3200 Phaethon, 2005 UD, and the Geminids are pieces of a main-belt comet precursor that disrupted, perhaps due to unsustainable internal gas"

Where main-belt comets are a new class of objects introduced by Jewitt& Hsieh in 2006. To say it with the words of Jewitt & Hsieh:

"Phaethon's true nature must still be considered an open question"

Below you can see our recent image (November 04) of this object (or click here )



by Ernesto Guido and Giovanni Sostero

References

- Meteor Showers and their Parent Comets by P. Jenniskens
- Search for activity in 3200 Phaethon by Hsieh & Jewitt (2005)
- Physical Observations of 2005 UD: a mini-Phaethon by Jewitt & Hsieh (2006)

Wednesday, October 8, 2008

2008 TC3 Update - Impact Flash Imaged from Satellite

Impact Flash Imaged from Satellite

While ground pictures of the fireball are still missing (the event occurred in a remote area over northern Sudan), it looks like finally there is an image of the impact flash.

The explosion was imaged by the weather satellite Meteosat 8.

The image is available at SpaceWeather.com: http://tinyurl.com/3r2ool



According to J. Borovicka, Astronomical Institute, Czech Academy of Sciences, the bright spot on the images taken by the weather satellite Meteosat 8 has been noticed by Z. Charvat. This bright spot likely corresponds to the atmospheric entry of 2008 TC_3 over northern Sudan (see - IAU Circular No. 8994).


Impactor 2008 TC3 entering Earth' shadow

Roughly one hour before expected atmospheric impact over northern Sudan, 2008 TC3 entered Earth' shadow becoming invisible until the impact.

The entry in the Earth' shadow has been imaged by La Sagra Sky Survey, Spain. Their nice image is here:



This image also shows a periodic light variation along the trail that indicates a fast rotation. The same effect is evident in the image obtained by italian astronomer Walter Boschin at the 3.58m diameter Telescopio Nazionale Galileo (TNG):


by Ernesto Guido

Tuesday, October 7, 2008

2008 TC3 Animation

Animation showing the motion of small asteroid 2008 TC3 few hours before entering Earth atmosphere. 

Images obtained at Remanzacco Observatory by G. Sostero, E. Guido & P. Camilleri.



video

Same animation on Youtube:

http://tinyurl.com/4o5o2u

by Ernesto Guido

Small Asteroid 2008 TC3 to hit Earth Tonight

On the morning of 06 October 2008, astronomer R. Kowalsky of Mount Lemmon Survey detected a small object (absolute magnitude H=30.4) now designated 2008 TC3.

According to NeoDys and Jpl Neo experts, the impact with the Earth atmosfere is almost certain and it should be at 0246 UTC of 07 October 2008. Fortunately this object is only a small chunk of rock few meters in size and should not survive passage through the atmosphere. In case some fragments should reach the ground, the impact zone has been located in the northern Sudan.

No damage is expected.

The entry in the atmosphere should be visible over northern Africa and possibly even over southern Europe.

Almost certainly 2008 TC3 will be the first impacting object discovered before entry into the Earth's atmosphere.

Here you can see our follow-up images of 2008 TC3 taken few hours before its entry in Earth's atmosphere  (click on the image for a bigger version):

The discovery mpec:
http://www.cfa.harvard.edu/mpec/K08/K08T50.html

By G. Sostero, E. Guido and P. Camilleri

Friday, October 3, 2008

COMET P/2008 T1 (BOATTINI)

IAUC nr. 8988, published on 2008, Oct. 2, announces the discovery of another comet (his fifth) by Andrea Boattini, named P/2008 T1 (BOATTINI). This 18.th magnitude object has been found in Pisces, during the Catalina Sky Survey search, with a 1.5-m reflector. The discoverer reported a fairly condesed coma about 10-arcsec in diameter, and a fan-shaped tail nearly 1 arcmin long, in PA ranging 245-275 deg. After its posting on the Minor Planet Center's NEO-Confirmation Page, several observers confirmed its cometary nature, remarking the presence of the above mentioned broad fan tail toward West-Southwest. We confirmed it remotely from Mayhill (NM) through a 0.25-m, f/3.4 reflector + CCD around October 2.4. Eighty stacked 60-s unfiltered CCD exposures show a coma about 10" in diameter and a broad, fan-shaped tail about 40" toward p.a. 244 deg. Click on the image below for a bigger version.



Preliminary orbital elements published by the Minor Planet Center on M.P.E.C. 2008-T30:


provides a solution that points toward a "Jupiter family" object, with perihelion on February 2008 (e=0.29, q~ 3.02 AU, i~ 2.1 deg). Under these circumstances, it appears that this comet has experienced a close encounter with Jupiter around June 2002. In the next future, P/2008 T1 will gradually decrease its brightness, staying not far from the ecliptic for several months to came.

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

Wednesday, October 1, 2008

COMET C/2008 S3 (BOATTINI)

IAUC nr. 8986, published on 2008, Sept.30, announces the discovery of a comet by Andrea Boattini, named C/2008 S3 (BOATTINI). It has been found in Taurus, during the Catalina Sky Survey search, with a 1.5-m reflector. The discoverer reported a coma having a strong condensation and a coma about 10-arcsec in diameter, elongated toward PA 115-deg, with total magnitude about 18.5. After its posting on the Minor Planet Center's NEO-Confirmation Page, several observers confirmed its cometary nature.

We imaged it remptely from Mayhill (NM) through a 0.25-m, f/3.4 reflector + CCD around Sept. 30.4 (details on image):

http://tinyurl.com/3s6adt

Preliminary orbital elements published by the Minor Planet Center on M.P.E.C. 2008-S96 (http://www.cfa.harvard.edu/mpec/K08/K08S96.html) assume a parabolic retrograde orbit with perihelion on April 2011 (e=1, q~ 3.1 AU, i~ 158 deg). It's noteworthy the fact that the comet has been discovered to be active at about 8.3 AU from the Sun; this seems to indicate a rather "alive" object also at relatively high distances from our star.

Maxim brightness is supposed to be reached in the Summer of 2011, at about magnitude 12 (well placed in the sky for both hemispheres); obviously all the previous extrapolations are based on measurements conducted upon a very short arc of orbit, so they must be confirmed by further astrometric and photometric follow-up.

Updated ephemerids are available at the MPC webpage:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2008S3.html

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

Fly-by of the Apollo-type asteroid 2008 QS11

The asteroid 2008 QS11 has been discovered by the Siding Spring sky Survey (MPC code #E12) on 27 August 2008 at about magnitude 18.

The absolute magnitude of 19.8 suggests a diameter within a factor of two of 350 m (1). Due to its size and the proximity of its orbit to Earth's, this object has been classified as a "Potentially Hazardous Asteroid" by the Minor Planet Center. This object is also a target for the Goldstone Radar facility.

2008 QS11 (classified as an Apollo-type NEO) will reach on 02 October 2008 the minimum distance from Earth (0.02767 A.U.) with a maximum predicted brightness of about magnitude 14.

Here You can see the discovery mpec:

http://cfa-www.harvard.edu/mpec/K08/K08Q46.html

Below You can see our animation showing the motion of the asteroid in 30 minutes. At the moment of the shots 2008 QS11 was moving at 27"/min (magnitude 14):

http://tinyurl.com/46ttlx

By Ernesto Guido & Giovanni Sostero

(1) http://echo.jpl.nasa.gov/asteroids/2008QS11/2008QS11_planning.html

Friday, September 26, 2008

COMET P/2008 QP20 (LINEAR-HILL)

The IAU Circular nr.8979, issued on 2008 Sept. 24, annouces the discovery of a new comet: P/2008 QP20 (LINEAR-HILL). This object has been picked-up in Aries by R. E. Hill through the 0.68-m Schmidt telescope of the Catalina Sky Survey on 2008, Sept.23.3, and afterwards linked by K. Smalley (Minor Planet Center) with an object discovered by the LINEAR sky survey on 2008, Aug. 25.4. Hill's discovery report describe this 18-th comet as having a well condensed coma about 6 to 12 arcsec in diameter, and a narrow tail up to 4' long in PA 250-260 deg.

After its posting on the NEO-CP, several observers confirmed its cometary nature: in general, the comments pointed to a small coma, and a tail pointing toward south-west. We performed some follow-up of this object on Sept. 24.4, remotely from Mayhill (NM), and foud a coma about 10" in diameter and a narrow tail about 30" long in p.a. 233 deg (details on image):

http://tinyurl.com/3eldrr

The preliminary orbital elements published on M.P.E.C. 2008-S48 ( http://www.cfa.harvard.edu/mpec/K08/K08S48.html ), points toward a Jupiter-family comet (a~ 3.5 AU, e~ 0.5, i~ 8 deg, P~ 6.5 years); perihelion will be reached at the beginning of November 2008, at about 1.7 AU. The maximum brightness will be reached at the end of next October, at about magnitude 17; it will mostly remain a northern object.

Updated ephemerids are available at the Minor Planet Center:
http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2008QP20.html

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

Monday, September 22, 2008

COMET C/2008 S1 (McNAUGHT)

IAUC nr.8977, issued on 2008, September 19, announces the discovery of a 17-magnitude comet by R. H. McNaught about 2.5 deg. northwest of Antares (Alfa Scorpii). It was described by the discoverer, and afterward by several astrometrists that perfermed confirmatory follow-up, as having a coma about 8 to 30-arcsec in diameter, with an extension (tail or elongated coma) 10 to 20-arcsec long toward North-East.

We performed some follow-up of this object with a 0.25-m, f/6 reflector + CCD from the Moorook Observatory (Australia) on 2008, Sept. 18.5, founding an obvious coma nearly 12-arcsec in diameter:

http://tinyurl.com/4eq4je

Preliminary orbital elements, published on M.P.E.C. 2008-S10, assume a parabolic orbit, with inclination of about 18 deg, and perihelion on 2008, Sept. 21 (r~ 1.35 AU). The comet is now receding from both, Earth and Sun, and will get progressively fainter. Updated ephemerids are available at the Minor Planet Center website:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2008S1.html

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

COMET P/2008 R6 (GIACOBINI) = 205P/Giacobini

IAUC nr.8975, issued on 2008, September 10th, announces the discovery of a 15-magnitude comet by Koichi Itagaki and Hiroshi Kaneda in the Aquarius-Aquila border. It was described having a coma diameter of about 25-arcsec, and a tail 2-arcmin long pointing toward east-southeast. We performed some follow-up of this object with the 0.45-m, f/4.4 reflector + CCD from the Remanzacco Observatory (Italy) on 2008, Sept.10.8, and with the "Skylive" 0.30-m f/6 reflector at Catania, Italy, on Sept. 10.9.Also from our stackings the coma and tail of this comet was obvious:

http://tinyurl.com/3jnbwp

Maik Meyer suggested that this apparently new comet actually was a return of D/1896 R2 (Giacobini); this link was confirmed by Nakano.Updated ephemerids are available at the Minor Planet Center website:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/0205P.html

by Virgilio Gonano, Paul Camilleri, Ernesto Guido and Giovanni Sostero

New Comet C/2008 R3 (LINEAR)

IAUC nr.8973, published on 2008, September 8th, announces the discovery by the LINEAR sky survey, of a new comet, named C/2008 R3 (LINEAR). It has been found in Hercules on 2008, Sept. 7 at about magnitude 18; several observers performing its follow-up, found signs of cometary activity (coma diameter ranging from 8 ti 13-arcsec, tail of 15 to 20-arcsec toward PA about 130-deg).

Initially we observed it with the 0.30-m f/5.8 reflector at Trunkey, N.S.W., Australia, on Sept. 8.44-8.48, obsering a small coma about 12-arcsec in diameter. Further observations were obtained on 2008, Sept. 8.8 through a 0.45-m, f/4.4 reflector + CCD at the Remanzacco Observatory (Italy), where a deep stacking showed the presence of a coma and a broad tail toward South-East.

Here we post an animation (12 frames, 5 minutes exposure time each) obtained during such observing session:

video


Preliminary orbital elements from the Minor Planet Center (http://tinyurl.com/4577dd) assumes its orbit as parabolic, with an inclination of nearly 43-deg. Perihelion will be reached in November 2008, at r about 1.9 AU from the Sun. This comet is expected to reach a maximum magnitude of about 17, at its perihelion.

by P. Camilleri, G. Sostero and Ernesto Guido

Friday, September 5, 2008

Comet C/2008 R1 (GARRADD)

IAUC Circular No. 8969, published on 2008, Sept.4, informs that Gordon Garrad discovered a comet in the southern constellation of Grus, named C/2008 R1 (GARRADD). This object has been found on 2008, Sept. 2.5 through the 0.5-m schmidt at the Siding Spring observatory (Australia).

We performed some follow-up of this object remotely, from the Grove Creek-Skylive Observatory (Trunkey, Australia) on 2008, Sept. 2.7, by means of a 0.35-m, f/6.7 reflector + CCD.Our stacking of 24 unfiltered exposures, 120 seconds each, showed a tiny coma nearly 8 arcsec in diameter, elongated toward PA30 deg (details on image):

http://tinyurl.com/5rpan4

According to the preliminary orbital solution published on M.P.E.C. 2008-R22, this comet moves along a parabolic orbit, with i= 19 deg, and q= 1.7AU. Perihelium will be reached on November 2008. For te rest of this year it will mostly be a southern object, and the maximum magnitude is not expeted to be higher than 18.Updated ephemerids are available at the Minor Planet center website:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2008R1.html

by Paul Camilleri, Giovanni Sostero and Ernesto Guido

Recovery of COMET P/2001 R1 = 2008 Q4 (LONEOS)

The Electronic Telegram No. 1490, published by the CBAT on September 1, announced that M. Jaeger (Stixendorf, Austria) recovered P/2001 R1 (LONEOS) on 2008, Aug. 31.08719. He described the object as having a small coma and a tail about 3' in PA 275 deg.

After reading a comment of Jaeger, posted in the newsgroup [Comets-ml] about his recovery of this comet, we performed some follow-up observations of this object, remotely from Pedara (Italy) through the "Skylive" 0.3-m, f/6 reflector + CCD. Co-adding of 14 unfiltered exposures, 120 seconds each, obtained on 2008 September 1.1, showed the presence of a small coma, nearly 10 arcsec in diameter, of about magnitude 16.8, and a tail nearly 40 arcsec long, toward PA 280 deg.

Our image is available here:

http://tinyurl.com/6zokce

G. Sostero, E. Guido, P. Camilleri and V. Gonano

Recovery of 145P/Shoemaker-Levy

M.P.E.C. 2008-R06, published on 2008, September 1, announces the recovery of 145P/Shoemaker-Levy. This periodic comet has been recovered by the Siding Spring observatory on 2008, Aug 04.55491 and 26.56107. We performed some indipendent observations of this object in the course of our own search for its recovery, along three consecutive nights (2008, Aug, 26.54329 to Aug. 28.57171) remotely, through a 0.30-m f/5.8 reflector + CCd of the Skylive-Grove Creek Observatory (Australia).

In our stackings the comet appears as a featureless, stellar object, about magnitude 19, slowly moving in the southern constellation os Microscopium.

Our mosaic is available here (details on image):

http://tinyurl.com/5mgoah

G. Sostero, P. Camilleri and E. Guido

Wednesday, September 3, 2008

Possible Nova in Sco

Following the posting on the Central Bureau's unconfirmed-objects webpage about a possible nova in Sco, on 2008 Sep. 3.45 we performedsome follow-up of this object remotely, from Moorook (Australia),through a 0.1-m, f/5 refractor + CCD.

We can confirm the presence of a relatively bright object (unfilteredmagnitude about 9.6) at coordinates:

R.A. = 17h57m32s.93, Decl. =-30o43'10".3 (equinox 2000.0; UCAC-2 catalogue reference stars).

Comparison with an archive UK-Schmidt Red plate (obtained on 1992,June 03) show no counterparts at this precise coordinates; a nearbyfield star, with position end figures: 32s.95, 08".1, has magnitudeabout 18.

Our confirmation image is available here:

http://tinyurl.com/5w5e8u

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

Tuesday, September 2, 2008

Possible Nova in Centaurus

Following an alert note of Grzegorz Pojmanski, Dorota Szczygiel and Bogumil Pilecki of Warsaw University Astronomical Observatory, about their discovery of a possible nova in Centaurus at coordinates: A.R.= 14h 35m 03s; Decl.= -64o 06.4', through the ASAS3V instrument of The All Sky Automated Survey, we performed some follow-up of this object, remotely from the Skylive-Grove Creek Observatory (Trunkey, Australia).

Our LBVRI images, obtained on 2008 Sep. 2.4 to 2.5, through a 0.3-m, f/6 reflector + CCD, shows the presence of a relatively bright counterpart at coordinates:

R.A. = 14h35m02s.54, Decl. = -64o06'20".0 (equinox 2000.0; UCAC-2 catalogue reference stars).

Comparison with an archive Poss-2 Red plate (obtained on 1991, Jul.17) and with a Poss-2 Infrared plate (obtained 1981, Mar.02) show the presence at this coordinates of an extremely faint optical counterpart, at the detection limit of the plate. These are the results of our multicolor photometry (comparison stars HIP_71437 and HIP_71400): 2008, Sept. 2.39: B=9.54, V=8.63, R=8.03, I= 7.42; Sept. 2.46: B=9.69, V=8.70, R=8.10, I= 7.60 (accuracy about 0.05 magn. in each color). An estimation by P. Camilleri (Hurstville, NSW, Australia) performed on 2008, Sept. 2.48, through a 20x80 binocular, provides a visual magnitude of 8.4.

Our image is available here:

http://tinyurl.com/5mcxrs

by Giovanni Sostero, Ernesto Guido and Paul Camilleri

Friday, August 29, 2008

New Comet C/2008 Q3 (GARRADD)

IAU Circular nr.8968, issued on 2008, August 28th, announces the discovery by Gordon Garradd of a new comet, named C/2008 Q3 (GARRADD). It was picked-up in the southern constellation of Phoenix, through the 0.5-m Uppsala Schmidt telescope, on 2008 Aug 27.6.

The discoverer reported for it the detection of a 10" coma, more prominent toward north. After its posting in the NEO-CP page, A. C. Gilmore and P. M. Kilmartin confirmed indipendently the cometary nature of this object (small coma about 6 arcsec in diameter with no tail).

We performed some follow-up of this object on 2008, Aug. 28.6, using a remotely-controlled scope, located in Australia (Grove Creek Observatory). Looking at our stacking (details on image) we suspected the presence of a tiny coma, possibly elongated towad north, north-west:

http://tinyurl.com/6aqzd5

However the S/N in the stacks was not high enough to be sure about the reality of this details, and the sky conditions, initially very good, were rapidly deteriorating. So we lost the opportunity to perform during the same night additional follow-up of this target, in order to make sure about its cometary nature. Then we decided to get back into it the next nigth, but, meanwhile, its cometary nature was already published thanks to the IAU Circular nr.8968.

Preliminary orbital elements, published on M.P.E.C. 2008-Q52 (http://tinyurl.com/6ozaso), provide for this comet an eccentricity of e=1, and an inclination of i= 140 deg, that makes it moving along a retrograde orbit. Perihelion, at q= 2.5 AU will be reached in July 2009 (maximum magnitude is expected to be about 15). This comet will mostly be a southern object.

Updated ephemerids of C/2008 Q3 are available, as always, in the website of the minor planet center:

http://tinyurl.com/59xlud

During the same oberving session, we also performed some follow-up of the new discovered Aten-type minor planet 2008 QV11 (http://tinyurl.com/57tq56), a "chunk of rock", about 200-m in diameter, that was passing about 0.2 AU from Earth.

by Giovanni Sostero, Paul Camilleri and Ernesto Guido

New Comet C/2008 Q1 (MATICIC)

IAU Circular nr.8966, issued on 2008, August 20, announces the discovery by Stanislav Maticic of a new comet, named C/2008 Q1 (MATICIC).

The comet was discovered in the course of the Comet and Asteroid Search Program at Crni Vrh Observatory and reported as "a moving object of stellar appearance" about magnitude 18. After posting on the Minor Planet Center's 'NEOCP' webpage (designation 88I0001), several observers found this object to show cometary appearance.

Initially we observed it from MPC#B55 (Comeglians) on 2008 Aug. 19.8, through a 0.15-m, f/6 astrograph + CCD: in our stackings we found it rather "soft", compared to nearby field stars of similar brightness, with a possible appendage toward about East:

http://tinyurl.com/6xkth6

however due to the fact that the S/N of the image was not so high, we decided to collect some further observations, in order to discriminate about its possible cometary nature.

Then we observed it again from MPC#473 (Remanzacco) on Aug. 20.8, through a 0.45-m f/4.4 Newtonian reflector + CCD. This time the cometary nature of the object was clear: co-adding of 16 unfiltered exposures, 60 seconds each, showed that this object had a coma, with a diameter of about 10 arcsec, and a broad tail nearly 15 arcsec toward PA 122deg.

Our stacking is available here (details on image):

http://tinyurl.com/6eb555


Preliminary orbital elements published by the Minor Planet Center in M.P.E.C. 2008-Q30 (http://tinyurl.com/5dj5lf) assumes that this object moves along a parabolic orbit (i= 119 deg, q= 2.9 AU); perihelion will be reached at the end of December 2008. According the current ephemerids, this comet will reach its maximum brightness next April (m1~ 17.0).

Congratulations to Stanislav Maticic and to all the team at Crni Vrh Observatory.

by Virgilio Gonano, Ernesto Guido and Giovanni Sostero

Monday, August 4, 2008

Outburst of Comet 199P/Shoemaker

Prompted by an alert of Gustavo Muler about a possible outburst of 199P/Shoemaker, we perfomed some follow-up of this comet: we can confirm his initial observation of 2008, Aug. 3.9, that this comet is experiencing a bright phase. Co-adding of 30 unfiltered exposures, 60 seconds each, obtained on 2008, August 04.16 through a 0.25m, f/3.4 reflector + CCD (near Mayhill, NM) reveals the comet as an obvious featureless star-like object of magnitude 14.7N.

Our stack is available here (details on image):

http://tinyurl.com/6ocgp7

Image enhancement techniques show also the presence of a fain external coma, about 25 arcsec in diameter. The total magnitude m1 calculated for an aperture of 25 arcsec in diameter is about 14.6; the afrho parameter (proxy of the dust abundance within the coma) has been found to be about 800 +/- 100 cm (however it must be said that for an outbursting comet, the afrho characterization is not very meaningful because we are lacking a steady state coma behaviour).

Anyway, this is our afrho plot:

http://tinyurl.com/6yyuqq

According to Minor Planet Center "dates of last observation of comets" website, 199P was last observed by Gustavo Muler (MPC #J47) at magnitude 17.9N on 14.92 July 2008.

by Ernesto Guido and Giovanni Sostero

Saturday, August 2, 2008

Comet C/2008 O2 (MCNaught)

This object was insert in the NEO-CP on 2008, July 28.6 with the ID code 8O56129. We performed some follow up from different sites: initially we imaged it on Jul. 28.9 with the Skylive-4 (0.3-m, f/6.3 reflector + CCD) scope (near Catania, Italy, MPC#B40). Since the sky conditions were not so good, we were unable to define for sure its nature (asteroid or comet?) so we decided to submit to the MPC only a couple of lines about its astrometric positions.

Afterward we picked it up on 29.1 from the private observatory of one of us (Gustavo Muler, Lanzarote, Spain, MPC#J47): here the stackings obtained through a 0.3-m schmidt-cassegrain + CCD clearly shown the presence of a small compact coma about 12 arcsec in diameter, and a short tail, nearly 30 arcsec long, toward PA 255; the total magnitude of this comet has been measured at 17.7. Then we performed some further follow-up on July 29.3 by means of a 0.25-m, f/3.3 reflector + CCD of the the RAS network (near Mayhill, NM, MPC#H06): here Ernesto confirmed the presence of a small tail about 25 arcsec long toward South-West.

Furthermore we observed it on on Jul. 30.6 with the Skylive-5 (0.3-m, reflector + CCD) scope (Grove Creek observatory, near Sidney, Australia, MPC#E16), obtaining additional astrometry.

According to the currently available orbital elements published by the Minor Planet Center (http://tinyurl.com/6depww), comet C/2008 O2 moves along an parabolic orbit. If the current (preliminary) orbital solution will be confirmed, this new comet McNaught will reach perihelion in 2009 November; at maximum magnitude it is expected to be a pretty binocular object, well placed for northern observers.

The picture of Gustavo Muler is available here (details on image):

http://tinyurl.com/6agyoy

by G. Sostero, E. Guido, G. Muler, J. Piquard, D. Bektesevic and A. Galant

Thursday, July 31, 2008

Recovery of Comet 59P/Kearns-Kwee

This periodic comet, 59P/Kearns–Kwee, has been recovered by us, on 2008, July 28 & 29, during the Visnjan School of Astronomy, an educational project aimed at the introduction of young talented students into the field of astronomy, organized every year by the Visnjan Observatory .

Two consecutive nights of follow up, as recommended by the Minor Planet Center, has been secured by means of the remotely controlled Skylive-4 telescope (0-30m, f/6.3 reflector + CCD) located in Catania, Italy (B40 – Skylive Observatory, Catania). 59P has been picked-up in the morning sky in Aries, significantly fainter than predicted (about magnitude 19) but very close to the expected position. In our stackings it appears as a faint dot of light, slightly wider than the nearby field stars of similar brightness. At recovery the comet was located about 2.8 AU from both, Earth and Sun. According to the Minor Planet Center, the last time of its observation was 2000, March 9 (Kuma Kogen Observatory).

Our recovery image. Click on it for a bigger version:


Comet Kearns-Kwee belongs to the Jupiter family comets; its period is nearly 9.5 years; at perihelion (March 2009) it will get as close as 2.3 AU from our star (beyond the orbit of Mars) while at aphelion it reaches 6.6 AU from the Sun (beyond Jupiter).

According to the current ephemerids, comet Kearns-Kwee will reach its maximum brightness at perigee, on November 2008: at that time it will shine at about magnitude 14, very well located (for northern observers) in the autumn constellation of Triangulum.

Updated orbital elements and ephemerids are available, as always, at the Minor Planet Center website.

by G. Sostero, E. Guido, J. Piquard, D. Bektesevic and A. Galant

Tuesday, July 15, 2008

Dust tail of Comet C/2007 W1 (Boattini)

Analyzing the images of comet C/2007 W1 (Boattini) obtained during the past nights, we found evidence of a dust tail in comet Boattini (click on the image below for a biger version):


This detail appeas as a broad fan-like structure, nearly 3 arcmin long, extending toward South-West; it almost overlap the long and narrow ion tail that has been observed since before perihelion. The dust tail becames readily visible after a simple Azimuthal Median Subtraction routine, that enhances any deviation from a "normalized" profile of the coma. Probably it was present also in our previous shots of the comet, however its visibility was strongly hampered because of the poor observing conditions (comet very low in the sky in the morning twilight).

Currently the solar elongation of C/2007 W1 is increasing, so we expect that this detail will be soon picked-up by a number of other observers, without any particular image-processing routine. Observers with CCDs are encouraged to follow-up its development, possibly using some red or infrared filters, in order to reduce the contribution of the gas coma and the ion tail.

G. Muler, G. Sostero and E. Guido

Saturday, July 12, 2008

Comet 6P/d'Arrest update

We imaged again periodic comet 6P/d'Arrest on 2008, July 11.96, from the Remanzacco Observatory (click on the image for a bigger version):


Image processing show the possible presence of a tiny coma, nearly 20 arcsec in diameter. The crowded stellar field hampers a sure identification of this feature, however this faint "halo" moves with the proper motion of the comet; moreover, the FWHM of the comet appears to be significantly larger compared to that of neary field stars of similar brightness, and this seems to confirm the presence of a detectable coma. The brightness of the comet has been measured at about magnitude 15 (Ru). This is still somehow fainter compared to the ephemerides (that indicates instead a visual total magnitude m1 equal to about magnitude 14), however we do know that i) CCDs magnitudes are frequently fainter than visual magnitudes and ii) the lightcurve of 6P/d'Arrest is known to show a striking asymmetric lightcurve, with lower pre-perihelion brightness. The Afrho parameter is still rather low (about 16-cm for a radius of nearly 3,000 Km at the comet distance).

Updated ephemerides are available (as always) at the Minor Planet Center website.

Giovanni Sostero and Ernesto Guido

Friday, July 4, 2008

Comet C/2007 N3 (Lulin)

On 2008, July 3.03 we performed some follow-up of C/2007 N3 (Lulin), through the 0.3-m, f/6.9 reflector + SBIG St8 XME CCD of one of us (Gustavo Muler, Observatorio Nazaret, Lanzarote, Spain), while the comet was moving in Capricornus. Geometrical circumstances at the moment of the observation: airmass: 1.52, T-152 days, delta~ 2.0 AU, r~ 2.9 AU and phase angle~ 10 deg.

Comet Lulin show a nearly circular coma, about 30 arcsec in diameter, slightly elongated toward North-West. Photometrically the coma show a very uniform profile, a kind of "disk", of nearly uniform brightness; just the outermost ~ 5 or 10 arcsec being very faint compared to the central part. This outlooking reminds somehow the aspect of 17P/Holmes shortly after its 2007 outburst (however this doesn't mean necessarily that these two comets share the same behaviour: it's just a morphological evidence!).

This is a link to the false colors image:
http://tinyurl.com/5n8f96

The same image, treated with an azimuthal median subtraction algorithm:
http://tinyurl.com/6h39n8

and a 1/r theoretical coma profile:
http://tinyurl.com/5otnkt

show clearly the unusual photometric morphology of the coma.

The total magnitude turned out to be Ru~ 12,7. Since we operated unfiltered, in our case the afrho parameter (proxy of the dust abundance within the coma) determination has just to be considered an upper limit; anyway it turned out to be a fairly high value, close to ~ 1,500 cm.

The photometric profile appears rather flat:
http://tinyurl.com/6af3r5

We acknowledge the use of the C.A.R.A. algorithms for the image processing (developed by Martino Nicolini) and the afrho calculations (develped by Roberto Trabatti).

Gustavo Muler, Giovanni Sostero and Ernesto Guido
http://www.cara-project.org/index.php

Monday, June 16, 2008

New Comet C/2008 L2 (HILL)

IAU Circular nr.8953, issued on 2008, June 15, announces the discovery by R. E. Hill of a new comet, named C/2008 L2 (HILL).

It was found with the 0.68-m schmidt of the "Catalina Sky Survey" on 2008, June 12.44, in the morning sky within Pegasus, and it has been described by the discoverer as having a coma diameter of 5"-14" with a diffuse, fan-shaped tail about 20 arcsec long in PA 250 degrees.

After posting on the Minor Planet Center's 'NEOCP' webpage, J. M. Aymani (Tiana, Spain) observing with a 0.25-m reflector + CCD, reported the dtection of a faint tail in PA 256 degrees.

We observed it remotely from Mayhill (NM) on 2008 Jun. 13.4, through a 0.25-m, f/3.4 reflector + CCD of the "Global Rent A Scope" network: in our stacking (co-adding of 42 unfiltered exposures, 60 seconds each) we could only appreciate that this object appeared slightly "soft" compared to nearby field stars of similar brightness.

Our stacking is available here (details on image):
http://tinyurl.com/47kwyk

Preliminary orbital elements published by the Minor Planet Center in M.P.E.C. 2008-L55 (http://tinyurl.com/5mtx5n) assumes that this object moves along a parabolic orbit (i= 25 deg, q= 2.5 AU); perihelion will be reached at the end of July 2008. According the current ephemerids, this comet will reach its maximum brightness next September (m1~ 17.2).

by Ernesto Guido and Giovanni Sostero

Tuesday, June 10, 2008

Recovery of Periodic Comet 61P/Shajn-Schaldach

M.P.E.C. 2008-L40, issued on 2008 June 9, report the recovery of the 61P/Shajn-Schaldach (it was last observed in 2001, Dec. 11). We picked-up this faint periodic comet on 2008, June 6.4, and confirmed it on June 7,4 while it was in Pisces, by means of a remotely-controlled telescope of the R.A.S. network (details on image):

http://tinyurl.com/5okxdm

In our stackings it appears as a faint smudge of light (magnitude nearly 18). No coma or tail can be appreciated in our images, however it must be said that when we imaged it, the comet was merely 20 degrees above the horizon, nearly lost in the morning twilight, so we cannot exclude that under better observing conditions further details could be glimpsed.

61P belongs to the "Jupiter family comets" class, it completes its elliptic orbit (a~ 3.7 AU, e~ 0.43, i~ 6 deg) every 7 years. It will reach perihelion at the beginning of September 2008; however, it is not supposed to get significantly brighter than magnitude 15 (this maximum in its lightcurve will be reached at perigee, around the end of October 2008).

Updated orbital elements and ephemerids are available at the Minor Planets Center's website:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/0061P.html

by Ernesto Guido and Giovanni Sostero

Periodic Comet 6P/d'Arrest

This comet has been recovered during its current return to perhelion by J. Hobart (Kachina Observatory) on 2008 Apr. 29.37, through a 0.36-m f/11.2 Schmidt-Cassegrain + CCD, while it was slowly moving in Ophiucus at m2~ 19.5.

It is supposed to became a relatively easy telescopic object in a few months from now; perihelion will be reached on 2008, August 14, while perigee will occour few days earlier).

We performed some follow-up observations on 2008, June 9 (details on image):

http://tinyurl.com/6zsq7v

In our stackings it appears as a faint starlike object (red magnitude close to 18) while it moves in a very rich Milky Way's star field in Aquila. Due to the star crowding, it is nearly impossible to distinguish any potential weak coma, if present.

by Giovanni Sostero and Ernesto Guido

Monday, June 2, 2008

Another Possible Nova in Ophiucus

Following the posting on the Central Bureau's unconfirmed-objects webpage about another possible nova in Ophiucus, today we performed some follow-up of this object remotely through a 0.25-m, f/3.4 reflector + CCD, near Mayhill (NM).

We can confirm the presence of a relatively bright counterpart at coordinates:
R.A. = 17h33m29s.62, Decl. = -27o 01'14".5 (equinox 2000.0; UCAC-2 catalogue reference stars).

Our multicolor photometry provides the following values: 2008, Jun. 2.23, B= +13.9, V= +12.8, R= +11.4 (accuracy +/- 0.1 magnitudes in each color).

Comparison with a UK Schmidt Telescope red plate, obtained on 1991, August 11 show nothing in this position (limiting magnitude near 20).

Our image of this transient is available at the following URL:

http://tinyurl.com/6nzldj

by E. Guido and G. Sostero (Remanzacco Observatory, Italy)

Monday, May 26, 2008

Possible Nova in Ophiucus

Following the posting on the Central Bureau's unconfirmed-objects webpage about a possible nova in Ophiucus, today we performed some follow-up of this object remotely through a 0.25-m, f/3.4 reflector + CCD, near Mayhill (NM).

We can confirm the presence of a relatively bright counterpart at coordinates:

R.A. = 17h39m50s.95, Decl. = -23o 50'00".9 (equinox 2000.0; UCAC-2 catalogue reference stars).

Our multicolor photometry provides the following values: 2008, May. 26.31, B= +11.42, V= +10.45, R= +9.81 (estimated accuracy +/- 0.05 magnitudes in each color).

Our image of this transient is available at the following Url:

http://tinyurl.com/64bw3x

Comparison with a UK Schmidt Telescope red plate, obtained on 1991, August 11 show nothing in this position (limiting magnitude near 20).

by E. Guido and G. Sostero (Remanzacco Observatory, Italy)

Sunday, May 25, 2008

Comet 7P/Pons-Winnecke

Prompted by a comment published on the newsgroup [Comets-ml] about a possible outburst of comet 7P/Pons-Winnecke detected by G. Muler, on 2008, May 23, we performed some follow-up of this object. Stacking of 30 unfiltered exposures, 60 seconds each, obtained remotely from Mayhill (NM) on 2008, May 25.2 through a 0.25-m, f/3.4 reflector + CCD, show that 7P/Pons-Winnecke currently has a diffuse coma nearly 25 arcsec in diameter, with a sharp central condensation.

Total magnitude m1 was measured to be R= 15.9. Preliminary afrho calculation provides a rather flat trend, with an average value of 30 +/- 5 cm.

Our image is available here:

http://tinyurl.com/62eyan

by Ernesto Guido and Giovanni Sostero

Monday, May 19, 2008

Comet 46P/Wirtanen

Prompted by a comment published on the newsgroup [Comets-ml] about a possible outburst of comet 46P/Wirtanen reported by M. Kidger and his spanish collaborators, we performed some follow-up of this object.

Stacking of 10 unfiltered expsoures, 50 seconds each, obtained remotely from Mayhill (NM) on 2008, May 18.2 through a 0.25-m, f/3.4 reflector + CCD, show that 46P/Wirtanen currently has a very compact coma nearly 15 arcsec in diameter. The total magnitude m1 was measured to be R= 14.8. Preliminary afrho calculation provides a rather flat photometric profile with a value ranging from 90 to 130-cm for apertures diameters passing from, respectively, 10,000 to 30,000-Km at the comet distance.

Our image is available here:
http://tinyurl.com/3vu75s

by Ernesto Guido and Giovanni Sostero

Friday, May 16, 2008

Comet C/2008 J6 (HILL)

IAU Circular nr.8945, issued on 2008, May 15, announces the discovery by R. E. Hill of a new comet, named C/2008 J6 (HILL).

It was found in the morning sky within Pegasus, with the 0.68-m schmidt of the "Catalina Sky Survey" on 2008, May 14.46, and it has been described by the discoverer as having a diffuse coma with a clear central condensation and a fan-shaped tail 1 arcmin long in p.a. 210 degrees.

After posting on the Minor Planet Center's 'NEOCP' webpage, several observers reported about its cometary nature (J. C. Pelle, N. Teamo, S. Nakano, Y. Ikari, J. E. McGaha and the undersigneds).

We observed it remotely from Mayhill (NM) on 2008 May 15.4, through the 0.25-m, f/3.4 reflector + CCD of the "Global Rent A Scope" network: we found a sharp central condensation about 8" in diameter, surrounded by a faint, extended coma about 25" in diameter (total mag about 15.5, nuclear magnitude about 16.6) and a fan-shaped tail 30" long toward the southwest.

Our image is available here:
http://tinyurl.com/5xtvkj

Preliminary orbital elements from the Minor Planet Center (http://tinyurl.com/5d9twg) assume that this object moves along a parabolic orbit (i= 46 deg, q= 2.1 AU); perihelion has been reached at the end of April 2008. According the current ephemerids, in the next future this comet will decrease its brightness.

by Ernesto Guido and Giovanni Sostero

Sunday, May 11, 2008

The Virtual Impactor Minor Planet 2008 HJ

After its posting on the NEO Confirmation Page with the NEO-Confirmation Page with code BK08329, follow-up was secured by a number of observers, among which our osservatory (M.P.C. Code #473).

Afterwards, M.P.E.C. 2008-H26 (http://tinyurl.com/4yg3d3), issued on 2008 April 25 , 20:51 U.T. , has announced the discovery of 2008 HJ: this is the tempoarary designation of the object, by the M.P.C. observatory code #704 Lincoln Laboratory ETS.

After few days, the asteroid has been catalogued as a "virtual impactor", because it has a very little probability that its orbit could be a threat for our planet; however currently it is flagged with a level "0" in the Torino scale. This situation could change, so these kind of minor planets are kept under strict monitoring by two istitutions , that are collecting the updated astrometric measurements about 2008 HJ : the Neo Object Program and Neo Dys Risk Page.

As suggested by the Minor Planet Center, it is mandatory to perform futher follow-up of this asteroid in next months, in order to improve the knowledge of its orbit with new measures. This is important to reduce the uncertains on orbital parameters and to confirm that 2008 HJ really belongs to the 0 class of Torino scale, that rappresents a very low level of hazard.

This image of 2008 HJ has been obtained by Remanzacco Observatory team in the same day of its discovery:

http://tinyurl.com/44y8bk

by Virgilio Gonano and Ernesto Guido

Thursday, May 8, 2008

Comet C/2008 J2 (BESHORE)

IAU Circular nr.8941, issued on 2008, May 7, announces the discovery by E. Beshore of a new comet named C/2008 J2 (BESHORE).

It was discovered with the 1.5-m reflector of the "Mount Lemmon Sky Survey" on 2008, May 6.44, and it has been described by the discoverer as having a bright condensed coma, diameter of 20 arcsec. Preliminary orbital elements from the Minor Planet Center show that this object moves along a parabolic orbit (i= 16.6 deg, q= 1.1 AU); perihelion is expected to occour on 2008 October 7th. According the current ephemerids, the new comet "Beshore" will reach approximately magnitude 8.5 at perihelion.

Soon after its posting in the M.P.C. NEO_Confirmation Page (around noon, April 6th) with the ID code "8JBD660", we wanted to get a close look at this relatively bright object, picked up just hours earlier. Unfortunately the weather conditions in our traditional observing site (Remanzacco Observatory, MPC code 473) were poor. So we decided to gave it a try from a new observatory (now under completion) that is operated by our astro club:

http://tinyurl.com/64takb (very large file!!!)

This new observing site is located about 20 Km East of Remanzacco, in the slopes of a nice mountain, named Mount Matajur. Since the Mount Matajur Observatory is 1340-m high, we hoped to skip at least some part of the haze that was affecting the plains were the Remanzacco observatory is located.

It was a wise decision, since while there, the sky suddently cleared up, so we were finally able to inaugurate our NEO/comets follow-up observing program from the recently "appointed" astrometric site MPC #B68!

When we located this relatively slow moving interloper in Ophiucus through a 0.2-m f/3 reflector + CCD, we initially considered it a star-like object (or at least, this was our very first impression looking at the single raw images that appeared on the PC monitor). However, when we carefully inspected the final stacking of 20 unfiltered exposures (60 seconds each) obtained on 2008, May 6.95, we immediately realized that this was not the case, since we noticed an extremely compact coma of almost uniform brightness about 20 arcsec in diameter, slightly elongated toward south-west:

http://tinyurl.com/68dzl6

The total magnitude m1 was measured to be R~14

Afterwards, we decided to continue the study of this comet candidate (still listed in the NEO-Confirmation Page as object "8JBD660") with the instruments of the "Rent A Scope" network. So, on 2008, May 7.3 we connected with a 0.25-m f/3.4 reflector + CCD located near Mayhill (NM), where we initially collected 10 unfiltered exposures, 60-seconds each, that we stacked. Analyzing the result, we were able to confirme the existence of a coma nearly 25 arcsec in diameter elongated toward PA 240 deg, with a very flat photometric profile:

http://tinyurl.com/6kbfh3

Filtered photometry performed soon afterwards (on 2008, May 7.37) through the same scope and a Cousins Red filter provided a total m1 magnitude of R~ 13.9, while a preliminary afrho calculation (proxy of the dust abundance within the coma) gave a value of nearly 450 +/- 80 cm; considering its current distance from the Sun, this seems to point toward an active comet.

by Giovanni Sostero and Ernesto Guido

Monday, May 5, 2008

Recovery of Periodic Comet 15P/Finlay

Periodic comet 15P/Finlay has been picked-up by the undersigneds on 2008, April 27.79 by means of a 0.25m, f/6 reflector + CCD (remotely, near Moorook, AU) and confirmed on 2008, April 28.70 through the same instrumentation.

Our astrometry:
0015P C2008 04 27.79053 22 58 27.09 -12 37 33.0 17.2 N EJ027D90
0015P C2008 04 27.79941 22 58 29.31 -12 37 19.0 17.5 N EJ027D90
0015P C2008 04 28.78638 23 02 33.02 -12 10 37.3 17.4 N EJ027D90
0015P C2008 04 28.79848 23 02 36.10 -12 10 18.9 17.5 N EJ027D90

According to the Minor Planet Center's website "Dates of last observation of comets" it was last observed on:
2002 03 30.42 14.0 T 340

W. H. Finlay (Royal Observatory, Cape of Good Hope, South Africa) discovered this comet with a 7-inch equatorial on 1886 September 26.83 (G. Kronk)

It's interesting to notice that, due to the proximity to Earth of its orbit (15P/Finlay is a Jupiter-family comet in a low inclination orbit just outside Earth's orbit), comet Finlay has been studied by several authors as a potential candidate for meteoroid delivering.

D.A.J. Seargent discussed a potential relation of the famous Murchison meteorite fall with 15P/Finlay:

http://tinyurl.com/3vmjt8

"Lubor Kresak identified comet 15P/Finlay as a likely source of meteor storms in the period 2004-2064. Neslusan and coworkers searched for photographed orbits in the IAU database, expecting activity around september 24, but no orbit could be linked to this comet. Martin Beech found that in the years 2001 and 2008 some meteoroids can make it toward the Earth's orbit, but Earth is not a the right time at that spot to cause a meteor outburst. (P.Jenniskens, 2006, chap. 19)

In a paper published in 1993, Z. Sekanina investigated about the orbital anomaly of 15P/Finlay (and few other periodic comets) as a result of the temporary activation of new discrete sources in cometary nuclei:

http://tinyurl.com/5k4zo9

The recovery image is available here:

http://tinyurl.com/6c47pq

by Ernesto Guido and Giovanni Sostero

References

G. Kronk, http://www.cometography.com/pcomets/015p.html
P. Jenniskens (2006), Meteor Showers and their Parent Comets
L. Kresak (1992), Meteor Storms. Meteoroids and Their Parent Bodies

Saturday, May 3, 2008

Comet C/2008 J1 (BOATTINI)

IAU Circular nr.8940, issued on 2008, May 3, announces the discovery by Andrea Boattini of a new comet (his second) named C/2008 J1 (BOATTINI).

It was picked-up with the 0.68-m schmidt of the "Catalina Sky Survey" on 2008, May 2.46, and it has been described by the discoverer as having a coma diameter of nearly 50 arcsec, and a fan-shaped tail 2 arcmin long toward PA 235 deg.After posting on the Minor Planet Center's 'NEOCP' webpage, a number of observers performed follow-up of this object.The undersigneds observed it through the 0.45-m, f/4.4 reflector + CCD of the Remanzacco Observatory (Italy) on 2008, May 3.0: we noticed a small compact coma, almost 15 arcsec in diameter, having a total magnitude of 14.7 (m2 nearly 15.5); an apparent tail spans almost 35 arcsec toward PA 280 deg.

Our image is available here:
http://tinyurl.com/5r2aco

Preliminary orbital elements from the Minor Planet Center (http://tinyurl.com/4d7pcj ) show that this object moves along a parabolic orbit (i= 46 deg, q= 1.5 AU); perihelion has been reached in the middle of March 2008. According the current ephemerids, the new comet "Boattini" will decrease its brightness as it will recede from both, Sun and Earth.

Congratulations to Andrea Boattini!

UPDATE (04 May 2008)

This is the discovery image of C/2008 J1 (Boattini) courtesy of Andrea Boattini:

http://tinyurl.com/52hehp

(30 seconds exposure by 0.68-m Schmidt + CCD)

by Virgilio Gonano, Giovanni Sostero and Ernesto Guido

Tuesday, April 29, 2008

Apollo asteroid 2008 HW1

M.P.E.C. 2008-H35 ( http://tinyurl.com/4l2wto ), issued on 2008 Apr. 28, 18:44 UT, announces the discovery of 2008 HW1, an apollo asteroid in a very comet-like orbit (Tj nearly 2.4; Jupiter family comets have Tisserand parameter TJ between 2 and 3). It was picked-up by the staff of Lincoln Laboratory ETS through a 1.0-m f/2.15 reflector + CCD, on 2008 April 25.35091. After its posting on the NEO Confirmation Page, further follow-up was secured by a number of observers. According the preliminary orbital elements published by the Minor Planet Center, 2008_HW1 moves along a very elongated orbit (e~0.96), that takes a little more than 4 years to be completed; at aphelion it approaches the orbit of Jupiter (Q~ 5 AU), while at perihelion (that will be reached in middle of next June) is passes only 0.1 AU - or nearly 15 Million Km - from the Sun. This is a rock whose diameter is supposed to range from nearly 600-m to 2-Km (depending on its surface reflectivity).

We performed some follow-up on 2008, April 28.0, from the Remanzacco Observatory (MPC #473):

http://tinyurl.com/6bd7du

In spite of its very comet-like orbit, in our stackings (total exposure time of 30 minutes) this object appears perfectly stellar, with no hints of any detectable coma or tail within our seeing limit.

by L. Donato, M. Gonano, V. Gonano, E. Guido, V. Santini and G. Sostero

Friday, April 25, 2008

Comet P/2008 G2 (SHOEMAKER)

IAUC nr.8939, issued on 2008, April 24, announces the recovery of P/1995 J3 = 1994k = 1994 XXVIII (Shoemaker), providing it the new designation P/2008 G2 (SHOEMAKER). It was picked up by T. Spahr, analyzing the astrometry of Apr. 10, reported by the Catalina Sky Survey (observer: R.A. Kowalsky, no comments about any potential cometary appearance) to the Minor Planet Center; linkage to further archive data of Apr.1 was provided by B. G. Marsden. The object was reported as having a magnitude of about 18.6.

We performed some follow-up of this comet on 2008, Apr. 24.9 from the Remanzacco Observatory (details on image):

http://tinyurl.com/43bygd

From our stacking we have evidence of a tiny coma, nearly 10 arcsec in diameter, possibly elongated toward North-West. The measured total magnitude is about 18.5 (R unfiltered).

Perihelion of P/2008 G2 (Shoemaker) will occur in April 2009. At that time the comet will have m1 nearly 17. The maximum brightness is expected to be just half a magnitude better, in August 2009, when the comet will mostly be a southern object.

by Giovanni Sostero and Ernesto Guido (AFAM-CARA, Italy)

Monday, April 21, 2008

New Comet C/2008 H1 (LINEAR)

Electronic Telegram No. 1343, issued on April 20th, announces the discovery by the Lincoln Near Earth Asteroid Research team of a 18.th magnitude comet in Ursa Minor:

C/2008 H1 (LINEAR)

It was picked-up on 2008, Apr. 18.34722 with a 1.0-m, f/2.15 reflector + CCD located in New Mexico (USA). After its posting on the Minor Planet Center's 'NEOCP' webpage, several observers performing its astrometric follow-up, reported about its cometary nature: in particular, E. Reina (April 19.0, Masquefa Observatory, Spain) commented about a magn. 16.6 coma almost 25 arcsec in diameter, and a 43 arcsec tail toward P.A. 233 deg. J. M. Aymami (April 19.8, Observatorio Carmelita, Spain) mentioned a suspected coma elongated toward P.A. 209 deg, while R. Apitzsch (April 19.8, Wildberg, Germany) noticed a tail toward southwest.

On April 19.5 we performed our own confirmation images, remotely through a 0.25m, f/3.4 reflector + CCD from the Rent A Scope network (Mayhill station, NM). The sky was clear, however the full Moon increased quite a lot the sky backgound noise; moreover, due to some technical problems, we couldn't stack more than 20 single unfiltered exposures, hampering our detections of very faint details. Anyway, also on our image, below the trail of a faint field's star, it's possible to appreciate the presence of this new comet, with the typical diffuse shape of this kind of objects.

With some image processing, from our image it's possible to notice a central condensation, surrounded by a ~30 arcsec diameter very faint coma, elongated toward South-West (details on image):

http://tinyurl.com/3nn7mz

A photometric analysis perfomed via Roberto Trabatti's Winafrho software (CARA's dedicated data reduction package), provides m2~ 18 (Ru) for the central condensation, and m1 ~16.5 (Ru) for the total coma brightness. The Afrho parameter (proxy of dust abundance within the coma) upper limit for this comet is then estimated to be nearly 90 +/- 30cm; considering that C/2008 H1 currently is at almost 2.8 A.U from the Sun past perihelium, this result seems to point toward a comet of modest activity.

Preliminary orbital elements published by the Minor Planet Center on M.P.E.C. 2008-H09 (http://tinyurl.com/4svhgw) show that this object moves along a very elongated and tilted orbit (e= 1, i= 76 deg); perihelion occured on 2008, March 11, with q~ 2.8 AU. According to the ephemerids (http://tinyurl.com/3lnug3), for the next few months this object will remain mainly a northern hemisphere target, and it will decrease its brightness from V~ 16.8 to nearly V~ 18.

by Ernesto Guido and Giovanni Sostero

Saturday, April 19, 2008

Possible Nova in Sagittarius

Prompted by an alert note published on the Central Bureau's unconfirmed-objects webpage about a possible nova in Sagittarius, today we performed some follow-up of this object through a 0.25-m, f/3.4 reflector + CCD remotely, near Mayhill (NM).

We can confirm the presence of a relatively bright counterpart at coordinates:

R.A. = 18h05m58s.90, Decl. = -27o 13'56".3 (equinox 2000.0; UCAC-2 catalogue reference stars):

http://tinyurl.com/3jjzod

by Ernesto Guido and Giovanni Sostero

Friday, April 11, 2008

Possible Nova in Cygnus

Prompted by an alert note published on the Central Bureau's unconfirmed-objects webpage about a possible nova in Cygnus, today we performed some follow-up of this object through a 0.25-m, f/3.4 reflector + CCD remotely, near Mayhill (NM).

We can confirm the presence of a relatively bright counterpart at coordinates:

R.A. = 19h43m01s.98, Decl. = +32o 19'13".5 (equinox 2000.0; UCAC-2 catalogue reference stars):

http://tinyurl.com/5o9sbj

by Giovanni Sostero and Ernesto Guido

Thursday, April 10, 2008

New Comet C/2008 G1 (GIBBS)

IAUC nr.8932, issued on 2008, April 9, announces the discovery of a new comet by A. R. Gibbs: C/2008 G1 (GIBBS); it was found through the 1.5-m reflector + CCD of the Mt. Lemmon Survey on 2008, April 7.36 while it was slowly moving in Serpens.

After its posting on the NEO-Confirmation Page as target "8GA7420", we performed some follow-up of this object from Remanzacco Observatory (MPC #473) and, remotely, through the Mayhill (NM) station of the "Rent A Scope" network.

The best image was that obtained from Remanzacco:

http://tinyurl.com/6gjgof

In our stackings from both sites, "8GA7420" showed its cometary nature, with a small coma, some 8 to 10 arcsec in diameter, and a short tail, 15 to 20 arcsec long toward South-SouthWest. The total magnitude m1 has been calculated as R~19.1, while the nuclear magnitude m2 was R~19.5. Preliminary orbital parameters published by the Minor Planet Center( http://tinyurl.com/5bn9jt ) show that this comet moves along a parabolic orbit (e=1, i=72 deg, q= 3.7 AU). It will reach perihelion on February 2009. This comet will be mostly a northern object, and it's not supposed to get any brighter than magnitude 18.

by Ernesto Guido, Giovanni Sostero, Luca Donato and Virgilio Gonano

Wednesday, April 9, 2008

Asteroid 2008 GS3

This Aten-type Near Earth Asteroid has been discovered by the Lincoln Laboratory ETS Sky Survey (MPC #704) on 2008, April 7.30; we performed its follow-up from the Remanzacco Observatory on 2008, April 7.9, while it was labeled as "BJ81650" in the NEO-CP webpage. At the beginning, it didn't show up in stackings, very likely because of the uncertainty of its ephemerids (the stacking we did was performed according the "best guess" preliminary speed and PA available at the moment).

On 2008 April 9.5, the object was still listed in the NEO-CP, but its ephemerids were considerably improved due to the follow-up astrometry produced by several observers. Then we re-stacked our original frames of the 7-8 April night with the new speed and PA, and we find it!

This is the astrometry we calculated:

COD 473
CON Piazza Ten.Col.G. Miani, nr.2 - 33047 Remanzacco (UD) ITALY
OBS L. Donato, M. Gonano, V. Gonano, E. Guido, V. Santini, G. Sostero
MEA L. Donato, M. Gonano, V. Gonano, E. Guido, V. Santini, G. Sostero
TEL 0.45-m f/4.4 Newtonian reflector + CCD
ACK MPCReport file updated 2008.04.09 14:17:58
NET UCAC-2
BJ81650 C2008 04 07.87868 13 13 47.28 -02 22 23.9 19.0 R 473
BJ81650 C2008 04 07.90497 13 13 39.75 -02 18 12.4 18.8 R 473


According to the preliminary orbital elements available at Minor Planet Center database, 2008 GS3 is a rock with an estimated diameter of nearly 100 meters, orbiting the Sun every 9.5 months. At perihelion it reaches at almost 80 Million Km from our star, between the orbits of Mercury and Venus, while at aphelion it approaches the Earth's orbit. When we imaged it, the asteroid was at 25 Million Km from our planet, moving at nearly 7.3 arcsec/min in Virgo, with a magnitude of nearly R~19:

http://tinyurl.com/5y25jw

Wednesday, March 26, 2008

Comet 7P/Pons-Winnecke

Comet 7P/Pons-Winnecke is currently approaching the Sun, during its journey to the inner Solar System. On 2008, March 25.9 we imaged it from the Remanzacco Observatory (Italy): after weeks of bad weather, a storm finally cleared up the sky, so we were able to perform some follow-up of this faint comet, while it was slowing moving in Ursa Major.

In our stacking (average of 20 unfiltered exposures, 120 seconds each, through a 0.45-m f/4.4 reflector + CCD) the comet appears starlike (no coma or tail are visible; same FWHM of the field stars):

http://tinyurl.com/2r8gwa

We performed a preliminary photometric analysis, that returned a magnitude of R~ 19.5; at this low level of activity, the afrho parameter (proxy of the dust abundance within the coma) is dominated by sunlight scattered by the nucleus, so it doesn't have a straightforward interpretation (just for the record, its current value is close to a few cm).

7P/Pons-Winnecke belongs to the Jupiter family cometary class (q~ 1.2 AU, Q~ 5.6 AU, i~ 22 deg, period~ 6.4 years). During its current approach, it has been recovered at magn.21 on 2007, Dec. 17 by K. Sarneczky (University of Szeged), 0.60-m Schmidt + CCD. It will reach perihelion at the end of September 2008, and it's not supposed to get any brighter than magnitude 12.5 at its best (but at small solar elongation).

C. Snodgrass et Al. [A&A 444, 287-295 (2005)] estimated the nucleus radius at ~2.2 Km, and bracketed its rotation period between 6.8 and 9.5 hours:

http://tinyurl.com/2dm2bd

This comet has been related to the June Bootids meteor stream, that was pretty active during some of the comet's passages in the first quarter of the past century. However the current activity of this meteor shower is rather modest, probably because the gravitation influence of Jupiter changed significantly the orbital path of the comet and its associated meteoroid debris.

Updated ephemerids for this object are available at the Minor Planet Center:

http://tinyurl.com/32ljzw

Giovanni Sostero and Ernesto Guido

Monday, March 10, 2008

Comet C/2008 E3 (GARRADD)

IAU circular nr.8927 published yesterday, announces the discovery of a new comet by Gordon Garradd, named C/2008 E3 (GARRADD). This object has been picked-up on 2008, March 5.8 on images obtained within the Siding Spring 0.5m Uppsala schmidt reflector + CCD.

We peformed some follow-up of this object by means of a remotely controlled scope of the "RAS" network (details on image):

http://tinyurl.com/2q43c8

In our stacking we can appreciate a coma nearly 10 arcsec in diameter, with a strong central condensation. Through strong enhancement of the visualization parameters, a faint and extended outer halo nearly 20arcsec in diameter, possibly elongated toward North-West, seems to be visible (however it must be said that in our frames this detail is very close to the background noise, and thus must be considered as uncertain).

It's also possible to see a faint and broad tail, extending nearly 20 arcsec toward North. We measured the central condensation as m2 almost 18.4, while the 10 arcsec coma has an m1 nearly 17.7 (both are unfiltered CCD magnitudes, approximated to R).

A preliminary afrho (proxy of dust abundance within the coma) measurement provides a value close to 450 +/- 100 cm; this seems to point toward a pretty active comet, considered that it's current distance from the Sun is r~ 5.5 AU.

The Minor Planet Center database points to a (preliminary) retrograde parabolic orbital solution:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2008E3.html

with an inclination on the ecliptic plane of i~ 107 degrees; perihelion will be reached at the end of next October, at 5.2 AU from the Sun.

C/2008 E3 (GARRADD) will remain a southern hemisphere object, and it's not supposed to get significantly brighter than magnitude 17.

Ernesto Guido and Giovanni Sostero

Wednesday, March 5, 2008

Comet C/2008 E1 (CATALINA)

IAUC nr. 8923, published yesterday, reports the discovery of a new comet: C/2008 E1 (CATALINA). It has been picked-up with the 0.68m Schmidt + CCD of the Catalina Sky Survey on 2008, Mar. 2.14.

According the report of several astrometrist that performed its follow-up, this object is rather faint (nearly magnitude 19) and is currently showing a small coma, 6 to 12 arcsec in diameter, elongated toward North-East.

We imaged it remotely from Mayhill, NM (details on image):

http://tinyurl.com/2rbof8

Preliminary orbital elements published on MPEC 2008-E41 (http://www.cfa.harvard.edu/mpec/K08/K08E41.html) points to a parabolic orbit, with e=1.0 and Incl.=34.3 deg; perihelion will be reached at the end of October 2008 (q=4.8 AU).

This comet is not supposed to get any brighter than V~17, so it shoud remain a rather unconspicuous object, in spite of the fact that it has a significative absolute magnitude, since we are currently observing it at Jupiter's distance.

Ernesto Guido and Giovanni Sostero

Monday, February 18, 2008

Comet C/2008 C1 (CHEN-GAO) Update

Comet C/2008 C1 (Chen-Gao) is currently crossing the rich Milky Way fields within Cassiopeia, not far from the 2.nd magnitude star Gamma Cas. This create some troubles performing its photometry & astrometry follow-up, due to the annoying stellar crowding that usually "pollutes" the cometary coma.

On 2008, Feb. 16.7, we obtained the "cometary first light" on a new scope, a MEADE LX200R 14" OTA, mounted on a 10Micron GM2000 QCI robotic mount (this will be the heart of our remote-controlled set-up, located in the new astronomical observatory atop Mount Matajur, currently under completion):

http://tinyurl.com/2neenf

Selecting a frame series relatively free from background stars, we did some follow-up about this comet. We found that the coma extends nearly 1 arcmin, with a relatively sharp central condensation (m2 almost 15.5). Total (unfiltered) magnitude is equal to 12.5. The Afrho parameter (proxy of the dust abundance within the coma) is ~150 +/- 25 cm, with a typical pattern:

http://tinyurl.com/3xyemj

(for more info's about the Afrho parameter importance, and and the role of amateur astronomers in its determination, please visit the CARA's webpage:
http://www.cara-project.org/index.php)

There are signs of a tiny tail extending toward North-East:

http://tinyurl.com/2864y6

This detail moves according the proper motion of the comet:

http://tinyurl.com/2ly9h9

so it's unlikely to be an artefact.

Wednesday, February 13, 2008

Is It an Asteroid, a Comet or Both?

There has been a time when asteroids and comets were regarded as quite different objects:

"At most meetings of professional astronomers during the 20th century, asteroids were discussed by one group and comets by a generally different group...it has taken decades to realize that these objects might share similar materials, or to allow the possibility of a smooth transaction from one group to the other, based on ice content" (W.K.Hartmann, 1999, chap.23)

The picture we have today is that of "planetesimals" whose composition difference reflects the temperature of the Solar System area where they formed. Comets, accreted beyond the Snow-Line, are ice-dominated object while asteroids are expected to be relatively ice-deficient.

So, traditionally, an object is defined as a comet when it shows a resolved coma at some point in its orbit:

"Deciding whether an object is an asteroid or a comet thus depends critically on the instrumental resolution and sensitivity to low surface brightness coma" (D.C. Jewitt, 2004)

Moreover as we know, comets pass through inactive phases giving rise to the situation where it's not possible to decide the nature of the object by the means of observations. Another clue of cometary nature of an object can arrive from its dynamical path. The Tisserand “invariant” calculated in respect to Jupiter (Tj) is often used as dynamical discriminator to distinguish the nature of Solar System objects. Comets-like objects have Tj < 3.

For all these reasons is not always easy to decide what classification to assign to some objects.

2005 WY3 is such an object. Discovered by Spacewatch Telescope survey, this asteroid is clearly moving on a typical cometary orbit (a= 6.74 AU, e= 0.74,P= 17.5 year, H= 13.4, Tj 2.116) but it never showed cometary activity.

We shoot 2005_WY3 few hours ago remotely from New Mexico (details on image):

http://tinyurl.com/3xvdgs

In our stacking this peculiar object has attained a good S/N (nearly 20) and shows no hints of cometary activity: its FWHM is identical to that of nearby field stars, with no traces of coma and/or tail. Either its cometary activity is currently well below the sensibility of our instrument, or there isn't any at all.

Ernesto Guido and Giovanni Sostero

References

Hartmann, W.K. (1999). Small World: Patterns and Relantionships in "The New Solar System"

Jewitt, D.C. (2004) From Cradle to Grave: The Rise and Demise of the Comets in "Comets II"

Sunday, February 3, 2008

Comet C/2008 C1 (CHEN-GAO)

We performed some follow-up of C/2008 C1 (CHEN-GAO) on 2008 Feb 3.10 through one of the R.A.S. units (details on image). In our stacking is visible a nice coma, nearly 1.5 arcmin wide. Image processing shows a clear elongation of the coma, and hint of a tail, toward North-East:

http://tinyurl.com/2rrgcn

Preliminary photometric data reductions returns a total (unfiltered) magnitude close to 13 The central condensation is nearly magn.16. The afrho parameter (proxy of dust abundance within the coma) is almost 80 cm +/- 20cm, with an asymmetric profile (higher values for wider apertures). Considering the current distance from the Sun (r nearly 1.6 AU, inbound) this amount seems to point toward a comet of moderate activity.

Congratulation to our chinese fellows for this nice find!

Ernesto Guido and Giovanni Sostero (A.F.A.M., C.A.R.A.)

Wednesday, January 30, 2008

Asteroid 2007 TU24 Close Approach Video

Asteroid 2007 TU24, discovered by the Catalina Sky Survey on October 11, 2007 has closely approached the Earth to within 1.4 lunar distances (334,000 miles) on 2008 Jan. 29 08:33 UT. We have observed this object from Remanzacco Observatory with a 45cm f/4.4 reflector and CCD FLI IMG 1001E. Below You can find our video composed of 100 images x 2 seconds showing this asteroid (magnitude 10) from 20h29m to 20h 45m UT.



2007 TU24 will be the closest currently known approach by a potentially hazardous asteroid of this size (between 150 and 600 meters in diameter) or larger until 2027.

Giovanni Sostero, Luca Donato ed Ernesto Guido

Sunday, January 20, 2008

Comet C/2008 A1 (McNaught)

Below you can see our image of comet  C/2008 A1 taken on 2008, Jan. 11.3. Click on the image for a bigger version:



In out stacking is possible to appreciate a nice coma, nearly 30arcsec across, elongated toward North-East. The total magnitude (unfiltered CCD) is nearly 15, while the Afrho calculation (proxy of the dust abundance within the coma) provide a value close to 670 +/-50 cm (with a photometric profile very flat between 15,000 and 40,000 Km from the central condensation).

This seems to indicate an active object, if we consider that currently this comet is nearly 4 AU from the Sun (inbound).The preliminary orbital elements, published by the Minor Planet Center in M.P.E.C. 2008-A48, show that this comet will remain a mainly southern object, with perihelion occuring in November 2008, and a total m1 considered to be nearly magn. 10 at its best.

Giovanni Sostero and Ernesto Guido

COMET P/2008 A2 (LINEAR)

IAUC nr. 8912, published yesterday, announces the discovery of a new periodic comet, P/2008 A2 by means of the LINEAR survey.

Preliminary orbital elements from the Minor Planet Center (see MPEC 2008-B18), report a short period Jupiter-family orbit, with P= 5.7 years, perihelion occuring on 2008, June 12 (q= 1.3 AU):

This comet is supposed to remain an unremarkable object, since its maximum brightness will be close to m1= 17.4, around the time of its perihelion. We imaged this object on 2008, Jan. 15.4 and 16.4, while it was in the NEO-CP. Click on the image below (36x60sec unfiltered exposures) for a bigger version:


In our stackings we didn't found any convincing evidence of a cometary features, probably because the extremely tiny coma reported by onlyone observer (J. Young, Table Mountain 0-61m reflector + CCD: 4"-6"diameter) was well below our threshold limit.

Ernesto Guido and Giovanni Sostero