Contents  on 9 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 9 December '13

One object reported inside ten LD

We have one object reported flying inside a radius of ten lunar distances (LD) from our home world today. Risk-listed 2013 XY8 enters Earth's Hill sphere, passing from 5.39 to 3.58 LD.

This report was updated at 1823 UTC to note today's DOU MPEC with the first follow-up for 2013 XY8. Today's first traffic report was generated at 1543 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.

NEOCP Activity  on 9 December '13

The MPC's NEO Confirmation Page has 27 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 27 objects listed. Of these, thirteen were "one nighters." So far The Tracking News has counted a total of 32 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 9 December '13

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 2013-X48 - "20:22 UT" - 2013 XY9

MPEC 2013-X47 - "19:49 UT" - 2013 XZ9

<< DOU on 9 Dec. '13 >>  MPEC 2013-X46 - "17:32 UT" - Daily Orbit Update

Observers  on 9 December '13

Seventeen observers appear in today's MPECs.

CodeObserver / observatory
E23Arcadia Obs. in New South Wales, 1 in MPEC 2013-X48 -- 2013 XY9
C77Bernezzo Obs. in Italy, 2 in MPECs 2013-X46 & 2013-X47 -- 2013 XZ9, 2013 XY8
160Castelmartini Obs. in Italy, 5 in MPEC 2013-X46 -- 2010 XZ67, 369264, 340666, 215188, 138095
703Catalina Sky Survey (CSS) in Arizona, 2 in MPECs 2013-X47 & 2013-X48 -- 2013 XZ9, 2013 XY9
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 12 in MPEC 2013-X46 -- 2013 WT44, 2013 VV4, 2013 VF13, 2013 VC10, 2013 JT22, 2013 JE1, 2012 FR62, 2011 SG5, 2009 XC2, 2009 VA1, 366733, 267759
958Dax Obs. in France, 2 in MPECs 2013-X47 & 2013-X48 -- 2013 XZ9, 2013 XY9
448Desert Moon Obs. in New Mexico, 1 in MPEC 2013-X46 -- 159399
J95Great Shefford Obs. in England, 1 in MPEC 2013-X48 -- 2013 XY9
5682David Tholen's team on Mauna Kea in Hawaii, 1 in MPEC 2013-X46 -- 2012 MO3
568_Marco Micheli on Mauna Kea in Hawaii, 1 in MPEC 2013-X46 -- 2013 WF108
B67Mirasteilas Obs. in Switzerland, 1 in MPEC 2013-X46 -- 2013 TL117
900Moriyama Obs. in Japan, 1 in MPEC 2013-X47 -- 2013 XZ9
A13Naef Obs. in Switzerland, 2 in MPEC 2013-X46 -- 2013 WA44, 162004
J43Oukaimeden Obs. in Morocco, 2 in MPEC 2013-X46 -- 65996, 377097
F51Pan-STARRS 1 in Hawaii, 1 in MPEC 2013-X46 -- 2013 XE2
K33San Defendente Obs., 1 in MPEC 2013-X47 -- 2013 XZ9
I93St. Pardon de Conques Obs. in France, 1 in MPEC 2013-X47 -- 2013 XZ9
Q621Hidetaka Sato in Japan via iTelescope Obs. Siding Spring in New South Wales, 1 in MPEC 2013-X46 -- 2009 WR25
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 9 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 XY8JPL Sentry20522091-209831.3e-04-4.05-4.050JPL: "Analysis based on 56 observations spanning 1.5922 days (2013-Dec-07.17005 to 2013-Dec-08.76222)." Diameter approximately 0.039 km. from mean, weighted H=24.7.
2013 XE2JPL Sentry20522029-2108181.7e-08-3.89-4.570JPL: "Analysis based on 25 observations spanning 1.9836 days (2013-Dec-03.62583 to 2013-Dec-05.60939)." Diameter approximately 1.100 km. from mean, weighted H=17.5.

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 9 December '13

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

2052Noted that JPL Sentry has posted 2013 XE2 as an impact risk - see above
Noted that JPL Sentry has updated its 2013 XY8 risk assessment - see above
Grabbed MPEC 2013-X48 - 2013 XY9 - see above
2000Grabbed MPEC 2013-X47 - 2013 XZ9 - see above
1823Updated Traffic Report
1822Grabbed MPEC 2013-X46 - Daily Orbit Update - see above