Main Belt object 596 Scheila in outburst early on 
12 Dec. (c)Copyright 2010 Great Shefford Obs.

Looking suddenly comet-like, there are so many questions now about 596 Scheila. Is it a Main Belt comet, not an asteroid? And is this activity, first noticed by the Catalina Sky Survey two days ago, due to an impact, such as occurred with P/2010 A2 (LINEAR), by what kind of impactor, and how long ago? The image here is from early yesterday, ©copyright 2010 Great Shefford Observatory, used with permission. See more images from observatories RAS Mayhill / Brimacombe, Remanzacco, Tzec Maun / Foglia, Vicksburg, and Xingming.

Contents  on 13 December '10


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 '10

Radar observation of one object

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

Data update noted at 2304 UTC when the database was dated 13 Dec.

NEOCP Activity  on 13 December '10

The MPC's NEO Confirmation Page has 1 listing: 1 new

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had one new listing. So far The Tracking News has counted a total of eight listings on the NEOCP at some point today.

New MPECs  on 13 December '10

Minor Planet Electronic Circulars

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

MPEC 2010-X109 - "13:57 UT" - 2010 XA59

MPEC 2010-X108 - "13:53 UT" - 2010 XZ58

MPEC 2010-X107 - "13:48 UT" - 2010 XY58

MPEC 2010-X106 - "13:39 UT" - 2010 XX58

MPEC 2010-X105 - "13:34 UT" - 2010 XW58

MPEC 2010-X104 - "13:28 UT" - 2010 XV58

<< DOU on 13 Dec. '10 >>  MPEC 2010-X103 - "07:09 UT" - Daily Orbit Update

MPEC 2010-X102 - "01:52 UT" - Comet P/2010 W1 (Gibbs)

Observers  on 13 December '10

A total of 23 observers appear in today's MPECs.

CodeObserver / observatory
J16An Carraig Obs. in Northern Ireland, 1 in MPEC 2010-X103 -- 2010 JL33
H21Astronomical Research Obs. Westfield in Illinois, 8 in MPEC 2010-X103 -- 2010 VW75, 2010 SJ15, 2010 RR80, 2010 PS65, 2010 PQ2, 2010 LU108, 2009 JO2, 2007 XB10
A81Balzaretto Obs. in Italy, 2 in MPEC 2010-X103 -- 2010 TM3, 2005 GC120
160Castelmartini Obs. in Italy, 12 in MPEC 2010-X103 -- 2010 XO10, 2010 XE11, 2010 XA24, 2010 WZ8, 2010 WL, 2010 WJ, 2010 VK188, 2010 TM3, 2010 RF181, 2010 LR68, 2010 JL33, 1620
703Catalina Sky Survey (CSS) in Arizona, 5 in MPECs 2010-X102, 2010-X103, 2010-X106 & 2010-X108 -- 2010 XZ58, 2010 XX58, 2010 XG3, P/2010 W1, 2010 LY63
176Consell Obs. in Spain, 1 in MPEC 2010-X103 -- 2010 XT45
106Crni Vrh Obs. in Slovenia, 1 in MPEC 2010-X103 -- 4954
595Farra d'Isonzo Obs. in Italy, 1 in MPEC 2010-X106 -- 2010 XX58
203GiaGa Obs. in Italy, 1 in MPEC 2010-X103 -- 2010 XT45
253Goldstone DSS-14 70m antenna in southern California, 1 in radar -- 2010 JL33
G92Jarnac Obs. in Arizona, 1 in MPEC 2010-X103 -- 138852
704LINEAR in New Mexico, 7 in MPEC 2010-X103 -- 2010 XG25, 2010 LR68, 2010 KH, 2008 YU32, 2006 VB14, 2004 BV1, 3288
H01Magdalena Ridge Obs. (MRO) in New Mexico, 6 in MPECs 2010-X104, 2010-X105, 2010-X106, 2010-X107, 2010-X108 & 2010-X109 -- 2010 XZ58, 2010 XY58, 2010 XX58, 2010 XW58, 2010 XV58, 2010 XA59
B90Malina River Obs. in Italy, 2 in MPECs 2010-X103 & 2010-X106 -- 2010 XX58, 2010 XM56
G96Mt. Lemmon Survey (MLS) in Arizona, 9 in MPECs 2010-X102, 2010-X103, 2010-X104, 2010-X105, 2010-X107 & 2010-X109 -- 2010 XY58, 2010 XW58, 2010 XV58, 2010 XA59, P/2010 W1, 2010 UF7, 2008 BU2, 170086, 3838
A24New Millennium Obs. in Italy, 1 in MPEC 2010-X106 -- 2010 XX58
A53Peschiera del Garda Obs. in Italy, 4 in MPEC 2010-X103 -- 2010 WQ7, 2010 LF86, 2010 JL33, 2006 VB14
H36Sandlot Obs. in Kansas, 2 in MPEC 2010-X103 -- 2010 XN25, 2010 WY8
204Schiaparelli Obs. in Italy, 15 in MPEC 2010-X103 -- 2010 XG25, 2010 XG, 2010 XA24, 2010 WG3, 2010 WF3, 2007 EM88, 2006 VB14, 2005 WE, 2005 VQ, 2003 SV222, 1999 XM141, 256412, 252091, 141498, 3838
587Sormano Obs. in Italy, 1 in MPEC 2010-X103 -- 2010 XM56
291Spacewatch 1.8m telescope in Arizona, 9 in MPECs 2010-X103 & 2010-X105 -- 2010 XW58, 2010 XR10, 2010 XG25, 2010 XC25, 2010 XB24, 2010 XB11, 2010 WZ8, 2010 VT11, 2010 VA76
C36Starry Wanderer Obs., 1 in MPEC 2010-X103 -- 2010 JL33
6734Mike Hicks via Table Mtn. Obs. in southern California, 1 in MPEC 2010-X103 -- 2010 JL33
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 13 December '10

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 CLOMON (backup) risk pages.





Notes for Today's Latest Risk Assessments
2010 XA59JPL Sentry17152012-2108364.3e-08-5.99-6.010JPL: "Analysis based on 15 observations spanning .08633 days (2010-Dec-13.448 to 2010-Dec-13.53433)." Diameter approximately 0.041 km. from mean, weighted H=24.6.
2010 XW58JPL Sentry17152014-2105245.7e-06-4.94-5.620JPL: "Analysis based on 19 observations spanning 2.0240 days (2010-Dec-11.47391 to 2010-Dec-13.49793)." Diameter approximately 0.040 km. from mean, weighted H=24.6.
2010 XO56NEODyS15572027-2087201.25e-07-4.26-4.480NEODyS: "Based on 17 optical observations (of which 0 are rejected as outliers) from 2010-12-11.468 to 2010-12-12.471."
2010 XC25JPL Sentry15572024-2097402.3e-05-2.05-2.520JPL: "Analysis based on 31 observations spanning 4.0181 days (2010-Dec-08.37716 to 2010-Dec-12.3953)." Diameter approximately 0.270 km. from mean, weighted H=20.5.
NEODyS15572024-2090492.25e-05-2.07-2.550NEODyS: "Based on 31 optical observations (of which 0 are rejected as outliers) from 2010-12-08.378 to 2010-12-12.396."
2008 EF85JPL Sentry1557211042.5e-07-7.79-7.980JPL: "Analysis based on 8 observations spanning 2.1314 days (2008-Mar-13.31126 to 2008-Mar-15.44269)." Diameter approximately 0.016 km. from mean, weighted H=26.7.

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 '10

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

2304Noted Radar Astrometry database update - see above
1715Noted that JPL Sentry has posted 2010 XA59 as an impact risk - see above
Noted that JPL Sentry has posted 2010 XW58 as an impact risk - see above
1557Noted that JPL Sentry has posted 2008 EF85 as an impact risk - see above
Noted that JPL Sentry has updated its 2010 XC25 risk assessment - see above
Noted that NEODyS has updated its 2010 XC25 risk assessment - see above
Noted that NEODyS has posted 2010 XO56 as an impact risk - see above
Grabbed MPEC 2010-X103 - Daily Orbit Update - see above
Grabbed MPEC 2010-X104 - 2010 XV58 - see above
Grabbed MPEC 2010-X105 - 2010 XW58 - see above
Grabbed MPEC 2010-X106 - 2010 XX58 - see above
Grabbed MPEC 2010-X107 - 2010 XY58 - see above
Grabbed MPEC 2010-X108 - 2010 XZ58 - see above
Grabbed MPEC 2010-X109 - 2010 XA59 - see above
0309Grabbed MPEC 2010-X102 - Comet P/2010 W1 (Gibbs) - see above