Contents  on 11 December '13

Asteroid/Comet Connection (A/CC) Resources:

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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 11 December '13

Two objects reported inside ten LD

There are two visitors reported to be within a radius of ten lunar distances (LD) from Earth today. Inside our planet's Hill sphere, risk-listed radar target 2013 XY8 comes its closest to Earth on this passage, reaching 1.98 LD at 1116 UT, and also its closest to the Moon -- 2.42 LD at 0318 UT. Out further, newly announced 2013 XH17 came its closest to Earth this time around, coming to 7.10 LD at 0026 UT.

This report was updated at 2352 UTC with new discovery 2013 XH17 (MPEC) and to note radar observation of 2013 XY8 posted yesterday and today. Today's first traffic report was generated at 1614 UTC with today's DOU MPEC reporting continuing follow-up for 2013 XY8, first follow-up for departed risk-listed 2013 XF4, and the recovery of distant risk-listed 2009 FD.



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 11 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 2119 UTC when the database was dated 11 Dec.

NEOCP Activity  on 11 December '13

The MPC's NEO Confirmation Page has 16 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had sixteen objects listed. Of these, ten were "one nighters." So far The Tracking News has counted a total of 32 listings on the NEOCP today.

New MPECs  on 11 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.


MPEC 2013-X56 - "21:05 UT" - 2013 XH17


MPEC 2013-X55 - "20:59 UT" - 2013 XG17


MPEC 2013-X54 - "16:52 UT" - 2011 GQ65


<< DOU on 11 Dec. '13 >>  MPEC 2013-X53 - "14:03 UT" - Daily Orbit Update

Observers  on 11 December '13

A total of 25 observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 3 in MPECs 2013-X54, 2013-X55 & 2013-X56 -- 2013 XH17, 2013 XG17, 2011 GQ65
I99Blanquita Obs. in Spain, 2 in MPEC 2013-X53 -- 21088, 12711
160Castelmartini Obs. in Italy, 7 in MPECs 2013-X53 & 2013-X55 -- 2013 XG17, 2013 UR3, 2010 XZ67, 2010 CL19, 251346, 215188, 138095
703Catalina Sky Survey (CSS) in Arizona, 9 in MPECs 2013-X53, 2013-X55 & 2013-X56 -- 2013 XH17, 2013 XG17, 2013 SK19, 2011 CQ4, 2009 BJ81, 2003 SJ215, 363790, 360433, 13651
470Ceccano Obs. in Italy, 1 in MPEC 2013-X53 -- 2013 XY8
309Cerro Paranal in Chile, 1 in MPEC 2013-X53 -- 2009 FD
958Dax Obs. in France, 2 in MPECs 2013-X55 & 2013-X56 -- 2013 XH17, 2013 XG17
448Desert Moon Obs. in New Mexico, 6 in MPECs 2013-X53 & 2013-X55 -- 2013 XY8, 2013 XG17, 2013 SK19, 1997 WQ23, 251346, 142464
253Goldstone DSS-14 70m antenna in southern California, 1 in radar -- 2013 XY8
I16IAA-AI Atacama in Chile, 1 in MPEC 2013-X53 -- 2013 XV8
H15ISON-NM Obs. in New Mexico, 1 in MPEC 2013-X53 -- 4954
W87LCOGT Cerro Tololo C in Chile, 1 in MPEC 2013-X53 -- 2013 XY8
H01Magdalena Ridge Obs. (MRO) in New Mexico, 2 in MPECs 2013-X55 & 2013-X56 -- 2013 XH17, 2013 XG17
C10Maisoncelles Obs. in France, 1 in MPEC 2013-X53 -- 3200
5682David Tholen's team on Mauna Kea in Hawaii, 3 in MPEC 2013-X53 -- 2013 XH4, 2013 XF4, 2013 DG
G96Mt. Lemmon Survey (MLS) in Arizona, 5 in MPEC 2013-X53 -- 2013 VY13, 2009 XZ1, 2009 BJ81, 1997 WB21, 187040
A24New Millennium Obs. in Italy, 16 in MPEC 2013-X53 -- 2013 UR3, 2010 XZ67, 89830, 55532, 53435, 52760, 361071, 251346, 21088, 16834, 162566, 138095, 137062, 12711, 9950, 1943
583Odessa-Mayaki Obs. in the Ukraine, 1 in MPEC 2013-X53 -- 142781
F51Pan-STARRS 1 (PS1) in Hawaii, 5 in MPEC 2013-X53 -- 2013 TE6, 376729, 370688, 8201, 3122
D29Purple Mtn. Obs. Xuyi Station in China, 17 in MPEC 2013-X53 -- 2013 TS4, 2013 TB80, 2010 SL13, 68031, 52760, 39565, 363790, 35432, 313538, 16834, 141079, 138947, 138013, 111253, 9950, 6178, 1943
B04Saint-Barthelemy Obs. in Italy, 1 in MPEC 2013-X55 -- 2013 XG17
H36Sandlot Obs. in Kansas, 2 in MPECs 2013-X53 & 2013-X56 -- 2013 XY8, 2013 XH17
204Schiaparelli Obs. in Italy, 3 in MPECs 2013-X53, 2013-X55 & 2013-X56 -- 2013 XY8, 2013 XH17, 2013 XG17
291Spacewatch 1.8m telescope in Arizona, 3 in MPECs 2013-X53, 2013-X55 & 2013-X56 -- 2013 XH17, 2013 XG17, 2008 AJ33
926Tenagra II Obs. in Arizona, 1 in MPEC 2013-X53 -- 2008 AJ33
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 11 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.
0000NNN000

Object

Risk
Monitor
When
Noted
UTC
0000T0000
Year
Range

VI
#
000NN00
Prob
Cum
T0000
PS
Cum
T0000
PS
Max

T
S


Notes for Today's Latest Risk Assessments
2013 XY8NEODyS16432086-211045.08e-04-3.40-3.40NEODyS: "Based on 152 optical observations (of which 8 are rejected as outliers) from 2013-12-07.171 to 2013-12-10.309."
JPL Sentry2320R E M O V E DJPL #2 for the day: Risk listing removed at 2203 UTC.
2013 XF4NEODyS1643R E M O V E D-
2013 XE2JPL Sentry1848R E M O V E DJPL #2 for the day: Risk listing removed at 1837 UTC.
NEODyS1614R E M O V E D-
2009 FDNEODyS20302185-219884.17e-04-2.43-2.65-NEODyS: "Based on 186 optical observations (of which 7 are rejected as outliers) from 2009-02-24.366 to 2013-12-02.330."
JPL Sentry17212185-219024.6e-04-2.38-2.60-JPL: "Analysis based on 179 observations spanning 1742.0 days (2009-Feb-24.36493 to 2013-Dec-02.32933)." Diameter approximately 0.130 km. from mean, weighted H=22.1.

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 11 December '13

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

2352Updated Traffic Report
2320Noted that JPL Sentry has removed 2013 XY8 as an impact risk - see above
2119Grabbed MPEC 2013-X55 - 2013 XG17 - see above
Grabbed MPEC 2013-X56 - 2013 XH17 - see above
Noted Radar Astrometry database update - see above
2030Noted that NEODyS has updated its 2009 FD risk assessment - see above
1848Noted that JPL Sentry has removed 2013 XE2 as an impact risk - see above
1721Noted that JPL Sentry has updated its 2009 FD risk assessment - see above
1702Grabbed MPEC 2013-X54 - 2011 GQ65 - see above
1643Noted that NEODyS has removed 2013 XF4 as an impact risk - see above
Noted that NEODyS has updated its 2013 XY8 risk assessment - see above
1633Noted that JPL Sentry has updated its 2013 XE2 risk assessment - see above
1614Noted that NEODyS has removed 2013 XE2 as an impact risk - see above
Grabbed MPEC 2013-X53 - Daily Orbit Update - see above
0018Noted that JPL Sentry has updated its 2013 XY8 risk assessment - see above