C/2011 W3 (Lovejoy) in STEREO-B view. 
Credit: Karl Battams, NRL/NASA.

Comet C/2011 W3 (Lovejoy) is on its way to a very close and probably fatal solar passage on December 16th. This is part of a frame from an animation compiled by Karl Battams of the Naval Research Lab from December 11th imagery from NASA's STEREO-B spacecraft. He has a running page with details and images as this event progresses.

Contents  on 13 December '11


The latest A/CC news is available via framed access, RSS news feed RSS news feed, or redirection. - Note: A/CC has a main Web site and also a backup site with its own duplicate RSS news feed.

Navigation tips: Use the << and >> arrows on the menus for each regular section (Observers, Risks, etc.) to move to the previous and next day's news for that section. Use the Index menu item to access specific days through a calendar interface. And use the all-up news archive to access news from any time since A/CC began in early 2002. To keep track of what's new each day, watch the Chronology section.

Radar Astrometry  on 13 December '11

Radar observation of two objects

The JPL Solar System Dynamics Group Radar Astrometry database has added or updated the following small-body radar observing work:

Data update noted at 0107 UTC when the database was dated 12 Dec.

Data update noted at 0206 UTC when the database was dated 12 Dec.

Photometry is needed for upcoming radar targets and also some astrometry. See Arecibo and Goldstone schedules.

NEOCP Activity  on 13 December '11

The MPC's NEO Confirmation Page has 1 listing

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had one object listed. This was a "one nighter."

New MPECs  on 13 December '11

Minor Planet Electronic Circulars

As of last check at 2359 UTC, there has been one MPEC posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

<< DOU on 13 Dec. '11 >>  MPEC 2011-X41 - "06:02 UT" - Daily Orbit Update

Observers  on 13 December '11

Six observers appear in today's MPEC.

CodeObserver / observatory
251Arecibo in Puerto Rico, 2 in radar -- 2005 FA, 8201
H21Astronomical Research Obs. Westfield in Illinois, 18 in MPEC 2011-X41 -- 2011 WP69, 2011 WO41, 2011 WN15, 2011 WK5, 2011 VS5, 2011 US63, 2011 TA4, 2011 SL102, 2011 RR12, 2011 QD48, 2011 FZ2, 2007 WU4, 2007 SP6, 2006 WO3, 2006 VY13, 2005 XM4, 2005 UJ159, 2004 JO2
379Hamamatsu-Yuto Obs. in Japan, 2 in MPEC 2011-X41 -- 2011 SL102, 2201
5682David Tholen's team on Mauna Kea in Hawaii, 2 in MPEC 2011-X41 -- 2011 SU67, 2011 QX8
A13Naef Obs. in Switzerland, 1 in MPEC 2011-X41 -- 1943
645Sloan Digital Sky Survey (SDSS) in New Mexico, 22 in MPEC 2011-X41 -- 2008 RY24, 2008 RP108, 2008 JT19, 2006 OZ, 2005 VJ1, 2005 QG30, 2003 RM, 2002 WP, 2002 RA182, 2002 PG80, 2001 PE1, 2000 SB25, 2000 FL1, 1999 EE5, 1998 YB8, 1998 VP, 1998 QB28, 39557, 288914, 285944, 280244, 276274
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 13 December '11

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS and JPL at 2359 UTC)
See the CRT page for a list of all objects rated recently as risks and our ephemerides page for a list of risk-listed objects under current observation.
The time horizon for JPL is 100 years from today and for NEODyS is usually the year 2090. Both also post impact solutions beyond 100 years for a few special objects.
For the latest official risk assessments, and for explanations of the terminology, see the JPL NEO Program Sentry and NEODyS CLOMON2 risk pages.





Notes for Today's Latest Risk Assessments
2011 WO41JPL Sentry16382042-205427.7e-10-4.71-4.840JPL: "Analysis based on 48 observations spanning 18.957 days (2011-Nov-23.48092 to 2011-Dec-12.43755)." Diameter approximately 1.600 km. from mean, weighted H=16.7.

Legend: VI# = VI count, Prob Cum = cumulative probability, PS Cum/Max = cumulative/maximum Palermo Scale, TS = Torino Scale

An impact solution, also known as a "virtual impactor" (VI), is not a prediction but rather a possibility derived from a variant orbit calculation that cannot be eliminated yet based on the existing data. Elimination can come quickly with just a little further observation or may take weeks or months, sometimes years. Once superceded or eliminated, a former impact solution has zero relevance to an object's risk. See Jon Giorgini's "Understanding Risk Pages" to learn more.

Chronology  on 13 December '11

Times are UTC for when items were noted or added by The Tracking News.

1638Noted that JPL Sentry has updated its 2011 WO41 risk assessment - see above
Grabbed MPEC 2011-X41 - Daily Orbit Update - see above
Noted that the NEOCP has become active
0206Noted Radar Astrometry database update - see above
0107Noted Radar Astrometry database update - see above