Contents  on 21 February '12

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 February '12

Four objects reported inside ten LD

Four objects are reported within ten lunar distances (LD) of Earth today. Within Earth's Hill sphere, risk-listed 2012 DX comes its closest to Earth this time, reaching 1.95 LD at 1819 UTC and 2012 DF4 comes its closest to Earth on this passage--3.35 LD at 0703 UTC. Further out, 2012 DZ travels from 7.67 to 4.35 LD and risk-listed 2012 CS46 from 8.5 to 7.0 LD*.

Approaching our neighborhood, 2012 DY and radar target 2011 CP4 arrive inside ten LD tomorrow, and 2008 EJ85 arrives inside ten LD on March 4th.

This report was updated at 1915 UTC with radar observation of 2011 CP4 (new) and follow-up in today's DOU MPEC for 2012 DZ, 2012 DY, 2012 DX, and 2011 CP4, as well departed 2011 YW15. This report was previously updated at 0540 and 0733 UTC.

Notes: 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. Distances are interpreted by A/CC from JPL Horizons data. "LD*" indicates some passage uncertainty. See also today's timeline plus current additional details and ephemerides.

Radar Astrometry  on 21 February '12

Radar observation of two objects

The JPL Solar System Dynamics Group Radar Astrometry database has added or updated the following small-body radar observing work:

Data update noted at 1912 UTC when the database was dated 21 Feb.

Data update noted at 2359 UTC when the database was dated 21 Feb.

NEOCP Activity  on 21 February '12

The MPC's NEO Confirmation Page has 3 listings

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

New MPECs  on 21 February '12

Minor Planet Electronic Circulars

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

MPEC 2012-D38 - "16:17 UT" - 2000 DO1

<< DOU on 21 Feb. '12 >>  MPEC 2012-D37 - "06:03 UT" - Daily Orbit Update

Observers  on 21 February '12

A total of 27 observers appear in today's MPECs.

CodeObserver / observatory
251Arecibo in Puerto Rico, 2 in radar -- 2011 CP4, 2008 QY
H21Astronomical Research Obs. Westfield in Illinois, 19 in MPEC 2012-D37 -- 2012 DZ, 2012 DY, 2012 DX, 2012 DN, 2012 CN46, 2012 CC17, 2012 CA21, 2012 BF77, 2012 BE14, 2012 AX, 2011 YW15, 2011 YS62, 2011 UP91, 2011 UH21, 2011 SQ12, 2011 OL51, 2005 BS27, 2002 LV, 99942
I47Auger Obs. in Argentina, 1 in MPEC 2012-D37 -- 1864
A74Bergen-Enkheim Obs. in Germany, 1 in MPEC 2012-D37 -- 2012 CC17
I99Blanquita Obs. in Spain, 1 in MPEC 2012-D37 -- 2012 BT23
703Catalina Sky Survey (CSS) in Arizona, 7 in MPECs 2012-D37 & 2012-D38 -- 2012 BC20, 2011 CP4, 2007 DK, 2000 DO1, 137802, 9400, 6053
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. in Chile, 1 in MPEC 2012-D37 -- 2012 DO
850Cordell-Lorenz Obs. in Tennessee, 1 in MPEC 2012-D37 -- 192642
G48Doc Greiner Research Obs. Rancho Hildalgo (DGRO-RH) in New Mexico, 5 in MPEC 2012-D37 -- 2012 DO, 2012 CD29, 2012 BT23, 2012 BJ134, 2011 YU74
113Drebach Obs. in Germany, 1 in MPEC 2012-D37 -- 2002 DJ5
379Hamamatsu-Yuto Obs. in Japan, 3 in MPEC 2012-D37 -- 2011 YV15, 2011 SL102, 192642
695]Mark Trueblood via Kitt Peak Natl. Obs. (KPNO) in Arizona, 2 in MPEC 2012-D37 -- 2012 BB124, 2011 VU5
704LINEAR in New Mexico, 6 in MPEC 2012-D37 -- 2011 CP4, 311554, 192642, 162038, 138524, 9400
C94MASTER-II Obs. Tunka in Russia, 1 in MPEC 2012-D37 -- 2011 YL6
H01Magdalena Ridge Obs. (MRO) in New Mexico, 2 in MPECs 2012-D37 & 2012-D38 -- 2012 BJ86, 2000 DO1
5682David Tholen's team on Mauna Kea in Hawaii, 1 in MPEC 2012-D37 -- 2012 CO46
474Mt. John Obs. in New Zealand, 1 in MPEC 2012-D38 -- 2000 DO1
G96Mt. Lemmon Survey in Arizona, 1 in MPEC 2012-D38 -- 2000 DO1
A13Naef Obs. in Switzerland, 2 in MPEC 2012-D37 -- 2002 AW, 172722
A24New Millennium Obs. in Italy, 20 in MPEC 2012-D37 -- 2012 AA11, 2011 XO3, 2011 WV134, 2006 AL8, 42286, 36284, 311554, 294739, 29075, 24475, 209924, 137805, 8567, 7358, 2368, 1943, 1866, 1627, 1620, 1036
C39Nijmegen Obs., 1 in MPEC 2012-D37 -- 2012 BJ134
F51Pan-STARRS 1 (PS1) in Hawaii, 6 in MPEC 2012-D37 -- 2012 CM29, 2012 CD29, 2008 PF1, 2007 DK, 2002 RD27, 171819
H23Pear Tree Obs. in Florida, 1 in MPEC 2012-D37 -- 2012 BJ134
H45Petit Jean Mtn. South Obs. (PJMSO) in Arkansas, 4 in MPEC 2012-D37 -- 2012 BT23, 2011 WV134, 2006 AL8, 143651
691Spacewatch 0.9m telescope in Arizona, 1 in MPEC 2012-D37 -- 2011 YM63
291Spacewatch 1.8m telescope in Arizona, 3 in MPEC 2012-D37 -- 2012 CA21, 2012 AC11, 2011 SJ68
I15Wishing Star Obs. in Rhode Island, 3 in MPEC 2012-D37 -- 2012 CC17, 192642, 7889
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 21 February '12

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
2012 DXJPL Sentry05392096-2111472.5e-05-5.92-6.330JPL: "Analysis based on 23 observations spanning .61322 days (2012-Feb-19.26892 to 2012-Feb-19.882139)." Diameter approximately 0.013 km. from mean, weighted H=27.1.
2012 DNNEODyS1709R E M O V E D-
JPL Sentry1709R E M O V E DJPL: Risk listing removed at 0853 UTC.
2012 CA21JPL Sentry17092043-210141.3e-05-1.96-1.971JPL #2 for the day: "Analysis based on 63 observations spanning 8.9948 days (2012-Feb-12.12022 to 2012-Feb-21.11501)." Diameter approximately 0.480 km. from mean, weighted H=19.3.
NEODyS17092073-207311.01e-05-2.08-2.081NEODyS: "Based on 63 optical observations (of which 3 are rejected as outliers) from 2012-02-12.121 to 2012-02-21.116."
2012 BJ86JPL Sentry17092105-211225.2e-07-4.83-4.860JPL: "Analysis based on 49 observations spanning 23.123 days (2012-Jan-29.10142 to 2012-Feb-21.22491)." Diameter approximately 0.160 km. from mean, weighted H=21.6.
NEODyS17092084-208417.7e-09-6.55-6.550NEODyS: "Based on 41 optical observations (of which 0 are rejected as outliers) from 2012-01-29.102 to 2012-02-21.226."

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 February '12

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

2359Noted Radar Astrometry database update - see above
1915Updated Traffic Report
1912Noted Radar Astrometry database update - see above
1709Noted that JPL Sentry has updated its 2012 BJ86 risk assessment - see above
Noted that NEODyS has reposted 2012 BJ86 as an impact risk - see above
Noted that JPL Sentry has updated its 2012 CA21 risk assessment - see above
Noted that NEODyS has updated its 2012 CA21 risk assessment - see above
Noted that JPL Sentry has removed 2012 DN as an impact risk - see above
Noted that NEODyS has removed 2012 DN as an impact risk - see above
Grabbed MPEC 2012-D38 - 2000 DO1 - see above
0733Grabbed MPEC 2012-D37 - Daily Orbit Update - see above
0539Noted that JPL Sentry has updated its 2012 CA21 risk assessment - see above
Noted that JPL Sentry has updated its 2012 DX risk assessment - see above