Contents  on 20 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 20 December '13

One object reported inside ten LD

There is one asteroid reported to be within ten lunar distances (LD) of Earth today. 2013 XH22 leaves our ten-LD reporting "bubble," passing from 6.80 to 11.03 LD.

Next "known" to be approaching is returning 2011 YD29, best calculated to arrive inside ten LD on December 23rd, but with an uncertainty of more than 17 hours.

This report was generated at 1536 UTC with follow-up in today's DOU MPEC for departed 2013 XY8.

Notes: Ten times the distance to the Moon (ten LD) has no astronomical significance but is a useful reporting boundary. 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 '13

The MPC's NEO Confirmation Page has 9 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had nine objects listed. Of these, two were "one nighters." So far The Tracking News has counted a total of fourteen 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 '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 20 Dec. '13 >>  MPEC 2013-Y12 - "14:02 UT" - Daily Orbit Update

Observers  on 20 December '13

Eleven observers appear in today's MPEC.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 6 in MPEC 2013-Y12 -- 2011 CQ4, 377097, 376729, 16834, 9950, 1627
160Castelmartini Obs. in Italy, 3 in MPEC 2013-Y12 -- 2013 UR3, 2010 XZ67, 251346
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 10 in MPEC 2013-Y12 -- 2013 XU3, 2013 XK22, 2013 WC44, 2013 UQ4, 2013 TE6, 2013 SK19, 2013 SF, 2013 QG17, 2011 SG5, 163132
A27Eridanus Obs. in Germany, 1 in MPEC 2013-Y12 -- 2013 XA4
5682David Tholen's team on Mauna Kea in Hawaii, 1 in MPEC 2013-Y12 -- 2007 MG
A24New Millennium Obs. in Italy, 5 in MPEC 2013-Y12 -- 2010 XZ67, 381906, 251346, 21088, 162566
D29Purple Mtn. Obs. Xuyi Station in China, 1 in MPEC 2013-Y12 -- 2013 TB80
G403Tony Evans in Portugal via Canary Islands Obs. in the Canary Islands, 1 in MPEC 2013-Y12 -- 2013 VD13
K90Sopot Obs., 1 in MPEC 2013-Y12 -- 2013 NX23
587Sormano Obs. in Italy, 1 in MPEC 2013-Y12 -- 2013 XY8
A84TUBITAK Natl. Obs. in Turkey, 1 in MPEC 2013-Y12 -- 1627
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 20 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
2013 XK22JPL Sentry18022042-2110247.2e-06-4.86-5.270JPL: "Analysis based on 37 observations spanning 5.9210 days (2013-Dec-14.43128 to 2013-Dec-20.35231)." Diameter approximately 0.052 km. from mean, weighted H=24.1.
2013 WV44JPL Sentry15352015-2112341.5e-08-6.52-6.830JPL: "Analysis based on 12 observations spanning 1.9534 days (2013-Nov-27.3572 to 2013-Nov-29.310622)." Diameter approximately 0.078 km. from mean, weighted H=23.2.
2013 UR1JPL Sentry1535205022.0e-06-6.62-6.670JPL: "Analysis based on 25 observations spanning 7.0358 days (2013-Oct-23.38002 to 2013-Oct-30.415818)." Diameter approximately 0.009 km. from mean, weighted H=27.8.

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 '13

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

1802Noted that JPL Sentry has updated its 2013 XK22 risk assessment - see above
1536Generated Traffic Report
1535Noted that JPL Sentry has updated its 2013 UR1 risk assessment - see above
Noted that JPL Sentry has updated its 2013 WV44 risk assessment - see above
Grabbed MPEC 2013-Y12 - Daily Orbit Update - see above