Contents  on 25 December '12

Asteroid/Comet Connection (A/CC) Resources:

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.

Traffic Report  on 25 December '12

Three objects reported inside ten LD

Three asteroids are reported to be within ten lunar distances (LD) of Earth today. Inside Earth's Hill sphere, radar target 2012 XM55 is outbound from 3.13 to 3.33 LD. Further out, 2012 YS1 departs from inside ten LD, traveling from 8.39 to 10.07 LD, and radar target intruder 2012 XB112 also exits, passing from 9.90 to 10.86 LD.

Coming toward Earth next, 2012 XP55 arrives inside ten LD tomorrow.

This report was generated at 1653 UTC with follow-up in today's DOU MPEC for departed objects 2012 XJ134 and 2012 XB133.

Notes: Ten times the distance to the Moon (ten LD) has no astronomical significance but is a useful reporting boundary. Earth's Hill sphere (of gravitational influence) is estimated to extend out to around 3.89 LD. Object distances are interpreted by A/CC from JPL Horizons data. See also current sky chart and object details (alt-details), ephemerides, and today's timeline.

NEOCP Activity  on 25 December '12

The MPC's NEO Confirmation Page has 54 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 54 objects listed. Of these, 27 were "one nighters." So far The Tracking News has counted a total of 55 listings on the NEOCP today.

To learn how observers use the NEOCP, see the Practical guide on how to observe NEOCP object at Suno Observatory by Birtwhistle et al.

New MPECs  on 25 December '12

Minor Planet Electronic Circulars

As of last check at 2358 UTC, there have been two MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

MPEC 2012-Y29 - "18:44 UT" - P/1999 D1 = 2012 Y2 (Hermann)

<< DOU on 25 Dec. '12 >>  MPEC 2012-Y28 - "06:04 UT" - Daily Orbit Update

Observers  on 25 December '12

Seven observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 21 in MPEC 2012-Y28 -- 2012 XT93, 2012 XT134, 2012 XS134, 2012 XJ134, 2012 XF112, 2012 XE133, 2012 XC112, 2012 XB133, 2012 US136, 1994 XD, 330825, 323179, 256412, 192563, 189173, 17188, 6569, 6455, 5646, 3908, 3838
703Catalina Sky Survey (CSS) in Arizona, 2 in MPEC 2012-Y28 -- 162900, 5587
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 8 in MPECs 2012-Y28 & 2012-Y29 -- P/2012 Y2, 2012 TZ52, 2012 QE50, 2001 SW269, 312070, 265661, 189040, 108519
448Desert Moon Obs. in New Mexico, 6 in MPEC 2012-Y28 -- 2012 XD112, 2012 WP3, 323179, 277127, 229672, 152667
5682David Tholen's team on Mauna Kea in Hawaii, 2 in MPEC 2012-Y28 -- 2012 XQ2, 2012 VQ76
G96Mt. Lemmon Survey in Arizona, 1 in MPEC 2012-Y28 -- 2008 SX7
F51Pan-STARRS 1 (PS1) in Hawaii, 11 in MPECs 2012-Y28 & 2012-Y29 -- P/2012 Y2, 2012 KU42, 2012 HJ1, 2009 BD2, 2008 YZ28, 2008 QY, 99907, 87684, 232368, 11405, 5131
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 25 December '12

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
2012 XE133NEODyS19002083-209644.25e-08-6.87-7.340NEODyS: "Based on 81 optical observations (of which 0 are rejected as outliers) from 2012-12-12.434 to 2012-12-23.150."
JPL Sentry16502083-209136.2e-08-6.70-7.030JPL: "Analysis based on 81 observations spanning 10.716 days (2012-Dec-12.43361 to 2012-Dec-23.14925)." Diameter approximately 0.069 km. from mean, weighted H=23.4.

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 25 December '12

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

1900Noted that NEODyS has updated its 2012 XE133 risk assessment - see above
Grabbed MPEC 2012-Y29 - P/1999 D1 = 2012 Y2 (Hermann) - see above
1653Generated Traffic Report
1650Noted that JPL Sentry has updated its 2012 XE133 risk assessment - see above
Grabbed MPEC 2012-Y28 - Daily Orbit Update - see above