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

New Comet Discovery: P/2009 QG31

IAU circular No. 9078, issued on 2009, Sept. 29, announces that an asteroidal object, discovered with a 0.45-m f/2.8 reflector + CCD by the "La Sagra Sky Survey" (Spain), has been reported to show cometary features by several observers, involved in its astrometric follow-up.

Our attention to this object with a peculiar orbit, has been drawn by one member of the "La Sagra" staff (R. Stoss, 2009 Sept. 10, private communication). Then we planned an observing campaign, asking some help to other fellow observers of the CARA collaboration (namely, P. Bacci, E. Bryssinck and R. Ligustri).

Our first attempt to investigate about the nature of this object, simply failed: the images obtained on 2009, Sept. 14, remotely from the Mayhill Station (NM) of the GRAS network, were of bad quality due to the presence of thin cyrrus clouds. Then, for several nights, bad weather conditions prevented us to perform further follow-up on it.

Finally, on Sept. 18.5, we succeed imaging it remotely with the 0.35-m f/7 reflector + CCD of the "Skylive" network (near Trunkey, Australia). At that time, the object was nearly 70 deg above the horizon, and the very good seeing allowed us to identify its tiny round coma, about 7-arcsec in diameter, having a total (unfiltered R) magnitude of about 19:

Further confirming observations were performed by other fellow observers we alerted, like the CARA memebers E. Bryssinck (remotely through the Tzec Maun 0.4-m reflector, NM, Sept. 16.3) and R. Ligustri (Talmassons, Italy, 0.35-m reflector; Sept. 19.9), who reported a coma ranging from 10 to 15-arcsec in diameter.

Other indipendent positive detections of cometary features on this object were performed by observers operating professional telescopes, like A. F. Tubbiolo and R. S. McMillan (Spacewatch 1.8-m reflector, Sept. 12.3), F. Hormuth (Calar Alto 3.5-m telescope, Sept. 17.9) and G. Muler (2-m Faulkes Telescope North, Sept. 18.4), that described a 10-15-arcsec diffuse coma.

According to the Minor Planet Center's database, this low-activity, Jupiter-family comet, completes a revolution around the Sun every 6.8 years, with a perihelion at about 2.1 Au from our star (that will be reached in Oct. 2009), and an aphelion at 5.0 AU; inclination above the ecliptic plane is about 5 deg. It's future visibility will be complicated by its declining brightness.

Congratulations to the "La Sagra Sky Survey" team for their discovery.

by G. Sostero, E. Guido, P. Camilleri, M. Jaeger, W. Vollmann, and E. Prosperi