Contents  on 20 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 20 December '12

Five objects reported inside ten LD

Five objects are reported to be inside ten lunar distances (LD) of Earth today. Radar target 2012 XM55 enters Earth's Hill sphere, flying from 3.90 to 3.54 LD. Out further, radar target intruder 2012 XB112 is outbound from 5.17 to 6.10 LD and the other three exit the ten LD "bubble." 2012 XP134 passes from 8.75 to 10.71 LD, risk-listed 2012 XM16 from 9.68 to 12.48 LD, and intruder 2012 XL134 from 9.72 to 11.94 LD.

Coming our way next, 2012 XP55 arrives inside ten LD on December 26th.

This report was generated at 1553 UTC with follow-up in today's DOU MPEC for 2012 XM55.

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 20 December '12

The MPC's NEO Confirmation Page has 11 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had eleven objects listed. Of these, eight were "one nighters." So far The Tracking News has counted a total of sixteen 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 20 December '12

Minor Planet Electronic Circulars

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

MPEC 2012-Y12 - "15:35 UT" - 2012 YO1

MPEC 2012-Y11 - "15:28 UT" - 2012 YN1

<< DOU on 20 Dec. '12 >>  MPEC 2012-Y10 - "06:04 UT" - Daily Orbit Update

Observers  on 20 December '12

Fifteen observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 10 in MPEC 2012-Y10 -- 2012 XM145, 2012 XJ55, 2012 XE17, 2012 VF37, 2012 VA5, 2012 US136, 2012 TQ78, 2012 TJ146, 2012 JT17, 345705
470Ceccano Obs. in Italy, 1 in MPEC 2012-Y12 -- 2012 YO1
448Desert Moon Obs. in New Mexico, 1 in MPEC 2012-Y12 -- 2012 YO1
J04ESA Optical Ground Station in the Canary Islands, 1 in MPEC 2012-Y11 -- 2012 YN1
E89Geyserland Obs. in New Zealand, 1 in MPEC 2012-Y10 -- 138937
704LINEAR in New Mexico, 11 in MPECs 2012-Y10 & 2012-Y12 -- 2012 YO1, 2012 XQ93, 2012 XC55, 2012 WP3, 2008 YZ28, 331509, 285110, 214869, 203471, 11405, 6569
H01Magdalena Ridge Obs. in New Mexico, 1 in MPEC 2012-Y11 -- 2012 YN1
188Majdanak Obs. in Uzbekistan, 1 in MPEC 2012-Y10 -- 99942
J43Oukaimeden Obs. in Morocco, 1 in MPEC 2012-Y10 -- 277127
261`program code "`" (30) using the Palomar Digitized Sky Survey in southern California, 1 in MPEC 2012-Y10 -- 2002 XQ40
204Schiaparelli Obs. in Italy, 3 in MPECs 2012-Y10, 2012-Y11 & 2012-Y12 -- 2012 YO1, 2012 YN1, 2012 XM55
645Sloan Digital Sky Survey in New Mexico, 1 in MPEC 2012-Y10 -- 2012 SF51
291Spacewatch 1.8m telescope in Arizona, 7 in MPECs 2012-Y10 & 2012-Y11 -- 2012 YN1, 2012 XZ132, 2012 XH55, 2012 XG16, 2012 XE133, 2012 XC133, 2012 XA133
C44Volta Obs. in Italy, 1 in MPEC 2012-Y12 -- 2012 YO1
I15Wishing Star Obs. in Rhode Island, 1 in MPEC 2012-Y10 -- 2012 XF112
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 20 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 XE133JPL Sentry15512083-209134.6e-08-6.85-7.180JPL: "Analysis based on 71 observations spanning 7.7455 days (2012-Dec-12.43361 to 2012-Dec-20.17914)." Diameter approximately 0.067 km. from mean, weighted H=23.5.
NEODyS15512083-209331.61e-08-7.30-7.580NEODyS: "Based on 71 optical observations (of which 0 are rejected as outliers) from 2012-12-12.434 to 2012-12-20.180."

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 20 December '12

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

1553Generated Traffic Report
1551Noted that JPL Sentry has updated its 2012 XE133 risk assessment - see above
Noted that NEODyS has updated its 2012 XE133 risk assessment - see above
Grabbed MPEC 2012-Y10 - Daily Orbit Update - see above
Grabbed MPEC 2012-Y11 - 2012 YN1 - see above
Grabbed MPEC 2012-Y12 - 2012 YO1 - see above