Contents  on 18 December '13

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 18 December '13

One object reported inside ten LD

There is one visitor reported to be within ten lunar distances (LD) of our planet today. Inside Earth's Hill sphere, 2013 XH22 comes its closest to Earth on this passage, reaching 1.93 LD at 1157 UT, and also its closest to the Moon -- 1.91 LD at 0606 UT.

This report was generated at 1757 UTC.

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.

Radar Astrometry  on 18 December '13

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 2150 UTC when the database was dated 18 Dec.

NEOCP Activity  on 18 December '13

The MPC's NEO Confirmation Page has 19 listings

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

New MPECs  on 18 December '13

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 18 Dec. '13 >>  MPEC 2013-Y09 - "14:01 UT" - Daily Orbit Update

Observers  on 18 December '13

Twelve observers appear in today's MPEC.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 2 in MPEC 2013-Y09 -- 2013 XW3, 2013 XV8
L22Barlad Obs., 3 in MPEC 2013-Y09 -- 2010 XZ67, 163696, 1627
C77Bernezzo Obs. in Italy, 1 in MPEC 2013-Y09 -- 21088
595Farra d'Isonzo Obs. in Italy, 1 in MPEC 2013-Y09 -- 2013 XG17
253Goldstone DSS-14 70m antenna in southern California, 1 in radar -- 2013 XH22
C94MASTER-II Obs. Tunka in Russia, 1 in MPEC 2013-Y09 -- 162566
C91Montevenere Obs., 2 in MPEC 2013-Y09 -- 251346, 162566
A13Naef Obs. in Switzerland, 1 in MPEC 2013-Y09 -- 162566
A53Peschiera del Garda Obs. in Italy, 2 in MPEC 2013-Y09 -- 2011 CQ4, 163696
H45Petit Jean Mtn. South Obs. in Arkansas, 1 in MPEC 2013-Y09 -- 2013 XA4
071Rhozen Obs. in Bulgaria, 1 in MPEC 2013-Y09 -- 163249
926Tenagra II Obs. in Arizona, 2 in MPEC 2013-Y09 -- 2013 XF22, 2013 WT67
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 18 December '13

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
2008 XKJPL Sentry04122015-2101704.3e-07-7.15-7.620JPL: "Analysis based on 12 observations spanning .08663 days (2008-Dec-02.28019 to 2008-Dec-02.36682)." Diameter approximately 0.012 km. from mean, weighted H=27.3.
2005 TM173JPL Sentry04122014-21101278.6e-07-5.42-6.290JPL: "Analysis based on 6 observations spanning 1.9467 days (2005-Oct-09.20072 to 2005-Oct-11.14743)." Diameter approximately 0.051 km. from mean, weighted H=24.1.

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 18 December '13

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

2150Grabbed MPEC 2013-Y09 - Daily Orbit Update - see above
Noted Radar Astrometry database update - see above
1757Generated Traffic Report
0412Noted that JPL Sentry has updated its 2005 TM173 risk assessment - see above
Noted that JPL Sentry has updated its 2008 XK risk assessment - see above