Contents  on 21 April '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 21 April '13

Two objects reported inside ten LD

Two objects are reported to be inside a radius of ten lunar distances (LD) from our home world today. 2013 GH66 is outbound from 4.87 to 5.16 LD and 2013 GH23 from 6.41 to 7.92 LD. No other objects are known to be approaching ten LD until late July.

This report was generated at 1358 UTC with follow-up in today's DOU MPEC for departed asteroids 2013 HO (first follow-up) and 2013 GD55 (doubling its observing arc to ten days).

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 21 April '13

The MPC's NEO Confirmation Page has 47 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 47 objects listed. Of these, seven were "one nighters." The Tracking News counted a total of 49 listings on the NEOCP on this day.

New MPECs  on 21 April '13

Minor Planet Electronic Circulars

There was one MPEC posted this day from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

<< DOU on 21 Apr. '13 >>  MPEC 2013-H25 - "06:05 UT" - Daily Orbit Update

Observers  on 21 April '13

Seventeen observers appeared in this day's MPEC.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 12 in MPEC 2013-H25 -- 2013 HO, 2013 GY68, 2013 GX79, 2013 GW68, 2013 GV68, 2013 GG, 2013 ET9, 2013 EL28, 2013 EC68, 2012 TA219, 2005 ND7, 2000 EV106
I99Blanquita Obs. in Spain, 2 in MPEC 2013-H25 -- 2013 FY13, 2009 SQ104
703Catalina Sky Survey (CSS) in Arizona, 3 in MPEC 2013-H25 -- 2013 FY13, 141670, 5645
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 8 in MPEC 2013-H25 -- 2013 GE55, 2013 GD55, 2013 EN126, 2013 EM89, 2013 CN35, 2013 CL89, 2013 AU27, 2012 TV78
448Desert Moon Obs. in New Mexico, 2 in MPEC 2013-H25 -- 54686, 263976
844Los Molinos Obs. in Uruguay, 1 in MPEC 2013-H25 -- 2013 EU9
C91Montevenere Obs., 3 in MPEC 2013-H25 -- 40267, 7888, 1866
G96Mt. Lemmon Survey (MLS) in Arizona, 4 in MPEC 2013-H25 -- 2013 GW68, 2012 SD22, 2011 MB2, 1996 TP6
I41Palomar Transient Factory in southern California, 1 in MPEC 2013-H25 -- 2008 SE85
F51Pan-STARRS 1 (PS1) in Hawaii, 5 in MPEC 2013-H25 -- 359592, 357594, 139289, 1917, 1866
H45Petit Jean Mtn. South Obs. (PJMSO) in Arkansas, 5 in MPEC 2013-H25 -- 2013 GV68, 2013 FY13, 2010 GY6, 2009 UM3, 1988 TA
C95SATINO-1 in France, 1 in MPEC 2013-H25 -- 2013 FY13
H36Sandlot Obs. in Kansas, 2 in MPEC 2013-H25 -- 2013 GY68, 2013 GW68
691Spacewatch 0.9m telescope in Arizona, 5 in MPEC 2013-H25 -- 2013 GR38, 2011 WU95, 2008 GB110, 354952, 136874
291Spacewatch 1.8m telescope in Arizona, 12 in MPEC 2013-H25 -- 2013 HR, 2013 GX79, 2013 GW79, 2013 GV79, 2013 GR66, 2013 GH84, 2013 GF69, 2013 GE84, 2013 GC34, 2013 FW13, 2012 DL31, 2006 WA
C36Starry Wanderer Obs. in Belarus, 1 in MPEC 2013-H25 -- 2013 FY13
2905Richard P. Boyle via Vatican Advanced Technology Telescope in Arizona, 1 in MPEC 2013-H25 -- 2012 XH16
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 21 April '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 HRJPL Sentry1349R E M O V E DJPL: Risk listing removed at 0951 UTC.
NEODyS1349R E M O V E D-
2013 GG69NEODyS1349R E M O V E D-
2013 GF69JPL Sentry13492030-2111121.3e-08-5.33-5.850JPL: "Analysis based on 21 observations spanning 9.9237 days (2013-Apr-10.42368 to 2013-Apr-20.34737)." Diameter approximately 0.419 km. from mean, weighted H=19.6.
NEODyS1349R E M O V E D-

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 April '13

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

1358Generated Traffic Report
1349Noted that JPL Sentry has updated its 2013 GF69 risk assessment - see above
Noted that NEODyS has removed 2013 GF69 as an impact risk - see above
Noted that NEODyS has removed 2013 GG69 as an impact risk - see above
Noted that JPL Sentry has removed 2013 HR as an impact risk - see above
Noted that NEODyS has removed 2013 HR as an impact risk - see above
Grabbed MPEC 2013-H25 - Daily Orbit Update - see above