New Comet: P/2010 U2 (HILL)

IAUC nr.9174, issued on 2010, Oct. 18, announced the discovery of a new periodic comet by R. E. Hill through the Catalina 0.68-m Schmidt telescope, on images obtained on 2010, Oct. 17.3. The new comet has been designated P/2010 U2 (HILL).

We performed some follow-up measurements of this object while it was still listed in the NEO-CP, on 2010 Oct. 17.5 and 18.3, remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD.

Analysis of two different series of 10 unfiltered stacked images, 120-seconds each, showed that this object appeared non-stellar. Through our images, we were unable to discriminate a definitive coma, however we measured on both nights its FWHM nearly 40% wider compared to that of nearby field stars of similar brightness, indicating a slightly diffuse nature at the threshold limit of our instrumental set-up and seeing conditions.

In our stackings of both nights, there was also a hint of elongation in a south-west to north-east direction (or the other way around, not easy to tell), while the field stars had an ordinary symmetrical profile. This might indicate the presence of a little tail or elongated coma, below our resolving power for that night (and, indeed, the discoverer reported a thin tail about 15"-20" long in p.a. 240 deg).

Our confirming image (click below for a bigger version):

This object was previously reported in a "one stand" night of observations by the "La Sagra" sky Survey, with observations dating back to 2010, oct. 1.1

Preliminary orbital elements published by the Minor Planet Center, assign to P/2010 U2 an elliptical orbit, with: T = 2010 Nov. 9.746 TT, e = 0.40365, q = 2.55669 AU, Peri. = 44.270 deg, Node = 357.247 deg, i = 16.910 deg, equinox 2000.0, P = 8.9 years

by E. Guido, G. Sostero, L. Donato & V. Gonano

Recovery of Comet 164P/Christensen

MPEC 2010-T98, issued 2010 October 13, reports our recovery of comet 164P/Christensen. We found the comet on October 07 and October 11, 2010 at about magnitude 20.4. We imaged it remotely from D96 code (Moorook) using a 0.15-m f/7.3 refractor + CCD.

On 2010, Oct.11 the seeing conditions at Moorook (Australia) were exceptional, so we had the chance to identify the comet at the very limit of our capabilities, as a faint dot of light (magnitude about 20.4). Then, knowing where to look for, we searched in our archive images, and found it again in our stackings of 2010, Oct. 7; then we had the astrometry over two nights, that was fitting pretty well the expected orbit of 164P.

However comet 164P/Christensen is much fainter (more than 3 magnitudes) compared to the predictions.

Our recovery image (details on image):

Comet 164P/Christensen was last observed (before our recovery) on June 18, 2005 by G96 (Mt. Lemmon Survey).

by G. Sostero, E. Guido, L. Donato & V. Gonano

Small Asteroid FlyBy: 2010 TD54

The small asteroid 2010 TD54 passed at about 45,500 kilometers above the Earth on October 12, 2010. The asteroid was discovered on October 09, 2010 by one of the telescope of the Catalina Sky Survey.

According to NASA JPL website, this small object is estimated to be about 5 to 10 meters wide. 2010 TD54 has zero probability of impacting Earth. Anyway objects of these size are expected to burn up high in the atmosphere and cause no damage to Earth's surface.

We have been able to follow-up 2010 TD54 few hours before its closest approach, on October 12 at 07:00UT (01:00am local time) through the GRAS network, using a scope located in Mayhill (NM). Below you can see our animation composed of 3 unfiltered exposures, 120-seconds each obtained by means of a 0.25-m, f/3.4 reflector + CCD:

Click below for a bigger version:

Below you can see a single 120-second exposure showing the asteroid as a trail among the field stars:

When we shoot our image this rock was speeding at about 220"/min, shining at about magnitude 15.6

By Ernesto Guido & Giovanni Sostero

New Comet: P/2010 T1 (McNAUGHT)

IAU circular No. 9172, issued on October 05, 2010, announces the discovery by R. H. McNaught of a diffuse comet on CCD images obtained with the 0.5-m Uppsala Schmidt telescope. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18.5 magnitude object, designated P/2010 T1 (McNAUGHT).

We have been able to confirm this object remotely, using a 0.15-m f/7.3 refractor at the Tzec Maun Observatory (near Moorook, Australia): on October 5.6, co-adding of 16 unfiltered exposures, 300-seconds each, shows a coma nearly 7-arcsec in diameter with a central condensation, and a broad fan-shaped tail about 12-arcsec long toward PA 310.

Our confirming image (click below for a bigger version):

The preliminary orbit for comet P/2010 T1 (McNAUGHT) shows perihelion on November 24, 2010, at about 3.2 AU. The period is about 10.2 years.

This is the 57th comet discovered by McNaught.

by G. Sostero, E. Guido, L. Donato & V. Gonano

New Comet: C/2010 S1 (LINEAR)

IAU circular No. 9170, issued on September 24, 2010, announces the discovery by the LINEAR survey of an apparently asteroidal object found to show cometary appearance by other CCD astrometrists. The discovery observation was obtained by LINEAR on Sept. 21.3 UT with a 1.0-m f/2.15 reflector + CCD. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18 magnitude object, designated C/2010 S1 (LINEAR).

We have been able to confirm this object remotely, through the GRAS network, using a scope located in Mayhill (NM): 0.25-m, f/3.4 reflector + CCD.: on Sept. 24.3, co-adding of 18 unfiltered exposures, 120-seconds each, show that this object appears soft compared to nearby field stars of similar brightness with a slight elongation in the east-west direction.

Our confirming image (click on the image for a bigger version):

The preliminary orbit for comet C/2010 S1 (LINEAR) shows perihelion on May 09, 2013, at about 4.4 AU.

According to COCD website, this is the 199th comet discovery for LINEAR.

by Ernesto Guido & Giovanni Sostero

New Comet: P/2010 R2 (LA SAGRA)

IAU circular No. 9169, issued on September 20, 2010, announces the discovery by La Sagra Sky Survey (LSSS) of a new comet on Sept. 14.9 UT with a 0.45-m f/2.8 reflector. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18.4 magnitude object, designated P/2010 R2 (LA SAGRA).

We have been able to confirm this object remotely, using a 0.15-m f/7.3 refractor at the Tzec Maun Observatory (near Moorook, Australia): on Sept. 17.6, co-adding of 12 unfiltered exposures, 300-seconds each, show a condensed coma nearly 10-arcsec in diameter.

Our confirming image (click on the image for a bigger version):

According to the IAUC No. 9169 & the latest orbital elements on MPEC 2010-S28, this object appears to be another "main-belt comet", similar to 133P = (7968) Elst-Pizarro.

This is the 4th discovery for the amateur survey La Sagra. Congratulation to the LSSS team members. The full discovery story has been posted on LSSS website.


by G. Sostero, E. Guido & L. Donato

Recovery of Comet 123P/West-Hartley

MPEC 2010-R111, issued 2010 Sept. 14, reports our recovery of comet 123P/West-Hartley. We found the comet on September 12, 2010 at magnitude 19.8. We imaged it from Malina River Observatory, Povoletto (B90) using a 0.25-m f/10 reflector + CCD.

We performed the second night of follow-up on September 13, 2010. In our stackings the comet appears shows a narrow tail about 15-arcsec long toward PA 267

Our recovery image (details on image):

Please click on the image for a bigger version.

Comet 123P/West-Hartley was last observed (before our recovery) on July 20, 2004 by Siding Spring Survey (E12).

by G. Sostero, E. Guido, L. Donato & V. Gonano