Contents  on 28 April '11

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.

NEOCP Activity  on 28 April '11

The MPC's NEO Confirmation Page has 31 listings: 7 new, 24 updated

When last checked at 0421 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had seven new and 24 updated objects listed. Of these, 27 were "one nighters." The Tracking News counted a total of 42 listings on the NEOCP on this day.

New MPECs  on 28 April '11

Minor Planet Electronic Circulars

There were ten MPECs posted this day from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.


MPEC 2011-H50 - "21:28 UT" - 2011 HO5


MPEC 2011-H49 - "21:22 UT" - 2011 HN5


MPEC 2011-H48 - "14:45 UT" - 2006 SO78


<< DOU on 28 Apr. '11 >>  MPEC 2011-H47 - "07:07 UT" - Daily Orbit Update


MPEC 2011-H46 - "01:29 UT" - 2011 HS4


MPEC 2011-H45 - "01:25 UT" - 2011 HR4


MPEC 2011-H44 - "01:20 UT" - 2011 HQ4


MPEC 2011-H43 - "01:12 UT" - 2011 HP4


MPEC 2011-H42 - "01:07 UT" - 2011 HO4


MPEC 2011-H41 - "01:02 UT" - 2011 GK71

Observers  on 28 April '11

Nineteen observers appeared in this day's MPECs.

CodeObserver / observatory
160Castelmartini Obs. in Italy, 4 in MPEC 2011-H47 -- 2007 VG184, 188174, 159399, 137170
703Catalina Sky Survey (CSS) in Arizona, 3 in MPEC 2011-H47 -- 2000 JE5, 162463, 136617
807|Robert Holmes via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 8 in MPECs 2011-H47, 2011-H48 & 2011-H50 -- 2011 HT, 2011 HP, 2011 HO5, 2011 GZ54, 2011 GQ65, 2011 GC, 2011 AL52, 2006 SO78
J18Churchstoke Obs. in Wales, 2 in MPEC 2011-H47 -- 2011 HT, 2011 HH
J95Great Shefford Obs. in England, 5 in MPECs 2011-H42, 2011-H43 & 2011-H47 -- 2011 HS, 2011 HP4, 2011 HO4, 2011 HJ, 2011 HH1
704LINEAR in New Mexico, 4 in MPEC 2011-H47 -- 2011 HQ, 89958, 267729, 169675
B67Mirasteilas Obs. in Switzerland, 2 in MPECs 2011-H42 & 2011-H47 -- 2011 HO4, 267729
474Mt. John Obs. in New Zealand, 6 in MPECs 2011-H41, 2011-H42, 2011-H44, 2011-H46 & 2011-H47 -- 2011 HS4, 2011 HQ4, 2011 HO4, 2011 HH, 2011 GK71, 2011 GB55
G96Mt. Lemmon Survey (MLS) in Arizona, 11 in MPECs 2011-H41, 2011-H42, 2011-H43, 2011-H44, 2011-H45, 2011-H46, 2011-H47, 2011-H49 & 2011-H50 -- 2011 HS4, 2011 HR4, 2011 HQ4, 2011 HP4, 2011 HO5, 2011 HO4, 2011 HN5, 2011 GX65, 2011 GK71, 159504, 4954
J93Mt. Tuffley Obs. in England, 3 in MPEC 2011-H47 -- 274138, 260141, 164121
A24New Millennium Obs. in Italy, 18 in MPEC 2011-H47 -- 2011 GF, 2011 GE, 2011 GC55, 2011 GB55, 2011 FS29, 2011 EM51, 2010 VN65, 2009 FT, 267759, 263976, 250614, 163696, 162463, 141531, 141432, 8176, 5626, 1866
D90`Kevin Hills in England via RAS Obs. Moorook in South Australia, 1 in MPEC 2011-H41 -- 2011 GK71
233San Vito Obs. in Italy, 1 in MPEC 2011-H47 -- 274138
H36Sandlot Obs. in Kansas, 3 in MPECs 2011-H46, 2011-H47 & 2011-H49 -- 2011 HS4, 2011 HN5, 2011 GX65
691Spacewatch 0.9m telescope in Arizona, 3 in MPEC 2011-H47 -- 250620, 141432, 4401
291Spacewatch 1.8m telescope in Arizona, 9 in MPECs 2011-H41, 2011-H47, 2011-H49 & 2011-H50 -- 2011 HO5, 2011 HN5, 2011 GN44, 2011 GK71, 2011 GJ44, 2011 GE2, 2011 FE41, 2011 FC29, 1997 QK1
I93St. Pardon de Conques Obs. in France, 1 in MPEC 2011-H42 -- 2011 HO4
926Tenagra II Obs. in Arizona, 2 in MPECs 2011-H46 & 2011-H50 -- 2011 HS4, 2011 HO5
D96Tzec Maun Obs. Moorook in South Australia, 1 in MPEC 2011-H41 -- 2011 GK71
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 28 April '11

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 CLOMON (backup) risk pages.
0000NNN000

Object

Risk
Monitor
When
Noted
UTC
0000T0000
Year
Range

VI
#
000NN00
Prob
Cum
T0000
PS
Cum
T0000
PS
Max

T
S


Notes for Today's Latest Risk Assessments
2011 HO5JPL Sentry23592024-21102324.2e-06-4.75-5.280JPL: "Analysis based on 15 observations spanning 1.0728 days (2011-Apr-27.39956 to 2011-Apr-28.47232)." Diameter approximately 0.062 km. from mean, weighted H=23.7.
2011 HP4NEODyS16092031-206855.27e-06-6.06-6.060NEODyS: "Based on 13 optical observations (of which 0 are rejected as outliers) from 2011-04-26.261 to 2011-04-28.008."
JPL Sentry0421203314.1e-06-6.17-6.170JPL: "Analysis based on 13 observations spanning 1.7475 days (2011-Apr-26.25983 to 2011-Apr-28.00737)." Diameter approximately 0.011 km. from mean, weighted H=27.5.
2011 HTJPL Sentry1609R E M O V E DJPL: Risk listing removed at 1050 UTC.
NEODyS1609R E M O V E D-
2011 HSJPL Sentry1609R E M O V E DJPL: Risk listing removed at 1129 UTC.
NEODyS1609R E M O V E D-
2011 GN44JPL Sentry1609206817.7e-08-3.49-3.490JPL: "Analysis based on 41 observations spanning 24.777 days (2011-Apr-03.44279 to 2011-Apr-28.2201)." Diameter approximately 0.710 km. from mean, weighted H=18.4.
NEODyS16092068-206814.5e-08-3.70-3.70NEODyS: "Based on 41 optical observations (of which 0 are rejected as outliers) from 2011-04-03.444 to 2011-04-28.221."

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 '11

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

2359Noted that JPL Sentry has posted 2011 HO5 as an impact risk - see above
2149Grabbed MPEC 2011-H49 - 2011 HN5 - see above
Grabbed MPEC 2011-H50 - 2011 HO5 - see above
1609Noted that JPL Sentry has updated its 2011 GN44 risk assessment - see above
Noted that NEODyS has updated its 2011 GN44 risk assessment - see above
Noted that NEODyS has posted 2011 HP4 as an impact risk - see above
Noted that JPL Sentry has removed 2011 HS as an impact risk - see above
Noted that NEODyS has removed 2011 HS as an impact risk - see above
Noted that JPL Sentry has removed 2011 HT as an impact risk - see above
Noted that NEODyS has removed 2011 HT as an impact risk - see above
Grabbed MPEC 2011-H47 - Daily Orbit Update - see above
Grabbed MPEC 2011-H48 - 2006 SO78 - see above
0421Noted that JPL Sentry has posted 2011 HP4 as an impact risk - see above
0139Grabbed MPEC 2011-H41 - 2011 GK71 - see above
Grabbed MPEC 2011-H42 - 2011 HO4 - see above
Grabbed MPEC 2011-H43 - 2011 HP4 - see above
Grabbed MPEC 2011-H44 - 2011 HQ4 - see above
Grabbed MPEC 2011-H45 - 2011 HR4 - see above
Grabbed MPEC 2011-H46 - 2011 HS4 - see above