Contents  on 28 April '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 28 April '12

Four objects reported inside ten LD

Four visitors are reported to be flying within ten lunar distances (LD) of our home planet today. Inside Earth's Hill sphere, radar target 2012 HM comes its closest to Earth on this passage, reaching 1.45 LD at 1005 UTC, and also its closest to the Moon -- 1.08 LD at 0746 UTC. And risk-listed 2012 HP13 exits the sphere, going from 2.90 to 5.40 LD.

Further out in the ten-LD "bubble," risk-listed 2012 HG2 is outbound from 7.99 to 8.78 LD and 2012 HN1 departs the bubble, traveling from 9.40 to 10.42 LD.

Up next, 1992 JD arrives inside ten LD on April 30th and 2010 KK37 on May 15th.

This report was updated at 1731 UTC with two new discoveries, both already departed: 2012 HD25 (MPEC) and 2012 HC25 (MPEC). Earlier, follow-up was reported in today's DOU MPEC for 2012 HP13, 2012 HM, and 2012 DA14. Today's first traffic report was generated at 1558 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 28 April '12

The MPC's NEO Confirmation Page has 31 listings

When last checked at 2227 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 31 objects listed. Of these, 22 were "one nighters." So far The Tracking News has counted a total of 53 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 28 April '12

Minor Planet Electronic Circulars

As of last check at 2227 UTC, there have been five MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

MPEC 2012-H80 - "14:09 UT" - 2010 KY39

MPEC 2012-H79 - "13:25 UT" - 2012 HD25

MPEC 2012-H78 - "13:21 UT" - 2012 HC25

MPEC 2012-H77 - "13:18 UT" - 2012 HB25

<< DOU on 28 Apr. '12 >>  MPEC 2012-H76 - "06:03 UT" - Daily Orbit Update

Observers  on 28 April '12

A total of 22 observers appear in today's MPECs.

CodeObserver / observatory
B03Alter Satzberg Obs. in Austria, 1 in MPEC 2012-H76 -- 2012 HP13
H21Astronomical Research Obs. Westfield in Illinois, 1 in MPEC 2012-H76 -- 2011 QD48
160Castelmartini Obs. in Italy, 1 in MPEC 2012-H76 -- 2012 HP13
703Catalina Sky Survey (CSS) in Arizona, 3 in MPEC 2012-H76 -- 184990, 138847, 3103
I39Cruz del Sur Obs. in Argentina, 1 in MPEC 2012-H76 -- 2004 RQ252
G48Doc Greiner Research Obs. Rancho Hildalgo (DGRO-RH) in New Mexico, 5 in MPECs 2012-H76 & 2012-H79 -- 2012 HL, 2012 HJ1, 2012 HD25, 2012 AA11, 2011 YV15
595Farra d'Isonzo Obs. in Italy, 1 in MPEC 2012-H79 -- 2012 HD25
F65%Tim Lister in southern California via Faulkes Telescope North in Hawaii, 1 in MPEC 2012-H77 -- 2012 HB25
C73Galati Obs. in Romania, 6 in MPEC 2012-H76 -- 2011 YV15, 2003 WH166, 1998 HE3, 86667, 53110, 162082
379Hamamatsu-Yuto Obs. in Japan, 3 in MPEC 2012-H76 -- 2012 AA11, 2011 YV15, 141018
695]Mark Trueblood via Kitt Peak Natl. Obs. (KPNO) in Arizona, 6 in MPEC 2012-H76 -- 2012 HM8, 2012 HJ1, 2012 GV17, 2012 FR1, 2012 FO62, 2012 CA21
704LINEAR in New Mexico, 4 in MPEC 2012-H76 -- 2012 AA11, 152754, 7341, 5836
5682David Tholen's team on Mauna Kea in Hawaii, 5 in MPECs 2012-H76 & 2012-H80 -- 2012 GX11, 2012 EW14, 2012 DA14, 2010 LM14, 2010 KY39
G96Mt. Lemmon Survey in Arizona, 1 in MPEC 2012-H78 -- 2012 HC25
J43Oukaimeden Obs. in Morocco, 1 in MPEC 2012-H76 -- 2010 LJ14
F51Pan-STARRS 1 (PS1) in Hawaii, 9 in MPECs 2012-H76, 2012-H77 & 2012-H79 -- 2012 HO2, 2012 HJ1, 2012 HD25, 2012 HC20, 2012 HB25, 2009 OC, 258325, 219527, 10636
854Sabino Canyon Obs. in Arizona, 1 in MPEC 2012-H79 -- 2012 HD25
691Spacewatch 0.9m telescope in Arizona, 3 in MPEC 2012-H76 -- 2012 HN13, 86667, 186822
291Spacewatch 1.8m telescope in Arizona, 5 in MPECs 2012-H76, 2012-H77 & 2012-H78 -- 2012 HO13, 2012 HM8, 2012 HG8, 2012 HC25, 2012 HB25
H78Univ. of Narino Obs. in Colombia, 1 in MPEC 2012-H76 -- 162421
B42Vitebsk Obs. in Belarus, 1 in MPEC 2012-H76 -- 2012 HM
G56Walnut Creek Obs. in northern California, 2 in MPEC 2012-H76 -- 2012 HL, 2012 GK
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 28 April '12

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS and JPL at 2227 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 HB25JPL Sentry15562016-21112103.3e-06-5.00-5.410JPL: "Analysis based on 13 observations spanning .99545 days (2012-Apr-24.35308 to 2012-Apr-25.348531)." Diameter approximately 0.037 km. from mean, weighted H=24.8.
2012 HP13NEODyS15562069-2090141.43e-06-5.56-6.180NEODyS: "Based on 164 optical observations (of which 12 are rejected as outliers) from 2012-04-22.461 to 2012-04-27.837."
2012 HG8JPL Sentry1556203011.9e-06-2.48-2.480JPL: "Analysis based on 136 observations spanning 7.0761 days (2012-Apr-20.25484 to 2012-Apr-27.33091)." Diameter approximately 0.370 km. from mean, weighted H=19.8.
NEODyS15562030-203015.8e-07-2.98-2.980NEODyS: "Based on 137 optical observations (of which 1 are rejected as outliers) from 2012-04-20.256 to 2012-04-27.332."
2012 GV17JPL Sentry1556205613.4e-10-7.60-7.600JPL: "Analysis based on 31 observations spanning 12.915 days (2012-Apr-14.34248 to 2012-Apr-27.25785)." Diameter approximately 0.190 km. from mean, weighted H=21.2.
NEODyS2105R E M O V E D-
2012 DA14JPL Sentry15562020-21111394.3e-04-3.14-3.750JPL: "Analysis based on 185 observations spanning 62.448 days (2012-Feb-23.03431 to 2012-Apr-25.482804)." Diameter approximately 0.045 km. from mean, weighted H=24.4.
NEODyS15562026-20901822.84e-04-3.29-3.840NEODyS: "Based on 188 optical observations (of which 4 are rejected as outliers) from 2012-02-23.029 to 2012-04-25.484."

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 28 April '12

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

2105Noted that NEODyS has removed 2012 GV17 as an impact risk - see above
1731Updated Traffic Report
1556Noted that JPL Sentry has updated its 2012 DA14 risk assessment - see above
Noted that NEODyS has updated its 2012 DA14 risk assessment - see above
Noted that JPL Sentry has updated its 2012 GV17 risk assessment - see above
Noted that JPL Sentry has posted 2012 HB25 as an impact risk - see above
Noted that JPL Sentry has updated its 2012 HG8 risk assessment - see above
Noted that NEODyS has updated its 2012 HG8 risk assessment - see above
Noted that NEODyS has updated its 2012 HP13 risk assessment - see above
Grabbed MPEC 2012-H76 - Daily Orbit Update - see above
Grabbed MPEC 2012-H77 - 2012 HB25 - see above
Grabbed MPEC 2012-H78 - 2012 HC25 - see above
Grabbed MPEC 2012-H79 - 2012 HD25 - see above
Grabbed MPEC 2012-H80 - 2010 KY39 - see above