Contents  on 21 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 21 December '13

No objects reported inside ten LD

There are no asteroids reported passing inside ten lunar distances (LD) of our planet today. Next known to be on approach is returning 2011 YD29, calculated to arrive inside ten LD on December 23rd but with an uncertainty of 17-plus hours.

This report was generated at 1605 UTC with follow-up in today's DOU MPEC for departed radar target 2013 NJ and astrometry from 2008 for risk-listed intruder 2008 CK70.

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 21 December '13

The MPC's NEO Confirmation Page has 4 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had four objects listed. Of these, two were "one nighters." So far The Tracking News has counted a total of nine 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 21 December '13

Minor Planet Electronic Circulars

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

<< DOU on 21 Dec. '13 >>  MPEC 2013-Y16 - "14:02 UT" - Daily Orbit Update

MPEC 2013-Y15 - "12:30 UT" - 2013 XU23

MPEC 2013-Y14 - "12:22 UT" - 2013 XT23

MPEC 2013-Y13 - "12:14 UT" - 2013 XS23

Observers  on 21 December '13

Sixteen observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 7 in MPEC 2013-Y16 -- 2013 TB80, 2002 VR94, 381906, 163696, 3200, 2212, 1627
160Castelmartini Obs. in Italy, 2 in MPEC 2013-Y16 -- 2013 NJ, 381906
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 6 in MPEC 2013-Y16 -- 2013 XU3, 2013 WT44, 2013 WC44, 2013 VV4, 2013 VF13, 2013 VD13
E103program code 3 via Faulkes Telescope South in New South Wales, 1 in MPEC 2013-Y16 -- 2062
844Los Molinos Obs. in Uruguay, 3 in MPEC 2013-Y16 -- 2013 XA4, 2102, 1980
C94MASTER-II Obs. Tunka in Russia, 1 in MPEC 2013-Y16 -- 3200
5682David Tholen's team on Mauna Kea in Hawaii, 1 in MPEC 2013-Y16 -- 2013 NJ
568_Marco Micheli on Mauna Kea in Hawaii, 1 in MPEC 2013-Y16 -- 2008 CK70
G96Mt. Lemmon Survey in Arizona, 1 in MPEC 2013-Y13 -- 2013 XS23
A24New Millennium Obs. in Italy, 5 in MPEC 2013-Y16 -- 89830, 53435, 361071, 137062, 1943
583Odessa-Mayaki Obs. in the Ukraine, 1 in MPEC 2013-Y16 -- 251346
C23Olmen Obs. in Belgium, 3 in MPEC 2013-Y16 -- 2013 XA4, 2010 XZ67, 251346
F51Pan-STARRS 1 (PS1) in Hawaii, 2 in MPECs 2013-Y14 & 2013-Y15 -- 2013 XU23, 2013 XT23
H23Pear Tree Obs. in Florida, 2 in MPEC 2013-Y16 -- 2013 XA4, 2013 TB80
104San Marcello Pistoiese Obs. in Italy, 1 in MPEC 2013-Y13 -- 2013 XS23
G403Tony Evans in Portugal via Canary Islands Obs. in the Canary Islands, 1 in MPEC 2013-Y16 -- 2013 XA4
291Spacewatch 1.8m telescope in Arizona, 3 in MPECs 2013-Y13, 2013-Y14 & 2013-Y15 -- 2013 XU23, 2013 XT23, 2013 XS23
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 21 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 XT23JPL Sentry16032055-206932.4e-09-8.53-8.630JPL: "Analysis based on 6 observations spanning .96227 days (2013-Dec-11.5596 to 2013-Dec-12.52187)." Diameter approximately 0.039 km. from mean, weighted H=24.7.
2008 CK70JPL Sentry1741R E M O V E DJPL: Risk listing removed at 1614 UTC.

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 21 December '13

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

1741Noted that JPL Sentry has removed 2008 CK70 as an impact risk - see above
1605Generated Traffic Report
1603Noted that JPL Sentry has posted 2013 XT23 as an impact risk - see above
Grabbed MPEC 2013-Y13 - 2013 XS23 - see above
Grabbed MPEC 2013-Y14 - 2013 XT23 - see above
Grabbed MPEC 2013-Y15 - 2013 XU23 - see above
Grabbed MPEC 2013-Y16 - Daily Orbit Update - see above