Comet C/2013 A1 (Siding Spring) passing Mars 
Illustration credit: NASA/JPL.

The NASA/JPL NEO Program Office issued a statement yesterday that Oort cloud object C/2013 A1 (Siding Spring) "will pass extraordinarily close to Mars" on October 19th of next year, and, based on a short five-month observation arc, "we can't exclude the possibility that the comet might impact Mars," putting the odds currently at less than one in 600. Illustration: NASA/JPL.

Contents  on 6 March '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 6 March '13

Two objects reported inside ten LD

There are two objects reported inside ten lunar distances (LD) of our planet today. Radar target 2013 ET is inbound from 9.69 to 7.15 LD and intruder 2013 EC exits ten LD, passing from 7.68 to 12.19 LD. Up next, 2007 EO88 (risk-listed radar target) is calculated with some uncertainty to arrive inside ten LD on March 15th.

This report was generated at 1431 UTC with follow-up in today's DOU MPEC for 2013 ET and departed risk-listed 2013 CL22.

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 6 March '13

The MPC's NEO Confirmation Page has 40 listings

When last checked at 2358 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 40 objects listed. Of these, 31 were "one nighters." So far The Tracking News has counted a total of 46 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 6 March '13

Minor Planet Electronic Circulars

As of last check at 2357 UTC, there have been five MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

MPEC 2013-E24 - "20:39 UT" - 2009 EM1

MPEC 2013-E23 - "12:00 UT" - 2013 EU9

MPEC 2013-E22 - "11:56 UT" - 2013 ET9

MPEC 2013-E21 - "11:51 UT" - 2013 ES9

<< DOU on 6 Mar. '13 >>  MPEC 2013-E20 - "06:05 UT" - Daily Orbit Update

Observers  on 6 March '13

A total of 28 observers appear in today's MPECs.

CodeObserver / observatory
A44Altschwendt Obs. in Austria, 1 in MPEC 2013-E21 -- 2013 ES9
E23Arcadia Obs. in New South Wales, 2 in MPECs 2013-E20 & 2013-E23 -- 2013 EU9, 2013 ET
A74Bergen-Enkheim Obs. in Germany, 1 in MPEC 2013-E20 -- 2013 ET
300Bisei Spaceguard Center in Japan, 2 in MPECs 2013-E20 & 2013-E24 -- 2013 EQ4, 2009 EM1
703Catalina Sky Survey (CSS) in Arizona, 9 in MPECs 2013-E20 & 2013-E24 -- 2012 CD29, 2009 UM3, 2009 EM1, 40267, 25916, 19764, 4179, 2368, 2329
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 10 in MPECs 2013-E20, 2013-E21, 2013-E22 & 2013-E23 -- 2013 EU9, 2013 ET9, 2013 ET, 2013 ES9, 2013 EA, 2013 DZ, 2013 DM1, 2013 CW35, 2013 CL89, 2013 CK129
822Cordoba Obs. in Argentina, 1 in MPEC 2013-E22 -- 2013 ET9
F65%Tim Lister in southern California via Faulkes Telescope North in Hawaii, 1 in MPEC 2013-E21 -- 2013 ES9
F658David Tholen's team in Hawaii via Faulkes Telescope North in Hawaii, 2 in MPEC 2013-E20 -- 2013 CL118, 99942
J95Great Shefford Obs. in England, 2 in MPECs 2013-E20 & 2013-E21 -- 2013 ES9, 2013 EP4
695`program code "`" (30) via Kitt Peak Natl. Obs. in Arizona, 1 in MPEC 2013-E20 -- 2013 ET
W85LCOGT Cerro Tololo A in Chile, 1 in MPEC 2013-E20 -- 2013 ET
711McDonald Obs. in Texas, 1 in MPEC 2013-E20 -- 2013 CL22
C91Montevenere Obs., 3 in MPEC 2013-E20 -- 99942, 25916, 154347
474Mt. John Obs. in New Zealand, 3 in MPECs 2013-E20 & 2013-E22 -- 2013 ET9, 2013 EA, 2013 CN35
G96Mt. Lemmon Survey (MLS) in Arizona, 8 in MPECs 2013-E20 & 2013-E24 -- 2013 CT36, 2012 SD22, 2009 EM1, 267221, 162011, 153220, 7358, 5189
F51Pan-STARRS 1 (PS1) in Hawaii, 13 in MPECs 2013-E20 & 2013-E21 -- 2013 ES9, 2013 CW35, 2012 TJ146, 2012 RV16, 2011 XZ1, 2006 DY, 2003 DC14, 27031, 267221, 207970, 162168, 141354, 7358
H23Pear Tree Obs. in Florida, 1 in MPEC 2013-E20 -- 2013 ET
H45Petit Jean Mtn. South Obs. (PJMSO) in Arkansas, 4 in MPEC 2013-E20 -- 2013 ET, 2013 EA, 2013 AU76, 2007 NS4
D29Purple Mtn. Obs. Xuyi Station in China, 2 in MPEC 2013-E20 -- 2009 UM3, 52387
104San Marcello Pistoiese Obs. in Italy, 1 in MPEC 2013-E22 -- 2013 ET9
H36Sandlot Obs. in Kansas, 5 in MPECs 2013-E20, 2013-E21, 2013-E23 & 2013-E24 -- 2013 EU9, 2013 ET, 2013 ES9, 2013 EA, 2009 EM1
204Schiaparelli Obs. in Italy, 1 in MPEC 2013-E22 -- 2013 ET9
E12Siding Spring Survey (SSS) in New South Wales, 2 in MPECs 2013-E22 & 2013-E23 -- 2013 EU9, 2013 ET9
510Siegen Obs. in Germany, 1 in MPEC 2013-E20 -- 2013 ET
291Spacewatch 1.8m telescope in Arizona, 1 in MPEC 2013-E20 -- 2013 DY
718Wiggins Obs. in Utah, 1 in MPEC 2013-E20 -- 2013 ET
H06iTelescope Obs. Mayhill in New Mexico, 1 in MPEC 2013-E20 -- 2013 ET
Q624program code 4 via iTelescope Obs. Siding Spring in New South Wales, 4 in MPEC 2013-E20 -- 2013 EA, 96315, 285263, 7888
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 6 March '13

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS and JPL at 2357 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 CL22JPL Sentry1428206436.6e-07-6.12-6.180JPL: "Analysis based on 79 observations spanning 28.289 days (2013-Feb-05.05792 to 2013-Mar-05.34736)." Diameter approximately 0.039 km. from mean, weighted H=24.7.
NEODyS14282064-206421.04e-07-6.92-6.960NEODyS: "Based on 79 optical observations (of which 3 are rejected as outliers) from 2013-02-05.059 to 2013-03-05.348."

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 6 March '13

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

2100Grabbed MPEC 2013-E24 - 2009 EM1 - see above
1431Generated Traffic Report
1428Noted that JPL Sentry has updated its 2013 CL22 risk assessment - see above
Noted that NEODyS has updated its 2013 CL22 risk assessment - see above
Grabbed MPEC 2013-E20 - Daily Orbit Update - see above
Grabbed MPEC 2013-E21 - 2013 ES9 - see above
Grabbed MPEC 2013-E22 - 2013 ET9 - see above
Grabbed MPEC 2013-E23 - 2013 EU9 - see above