Tuesday27 April 20044:48pm MDT2004-04-27 UTC 2248 back top next  

The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors


Today's issue status: done
yesterdayApriltomorrowIndex

Cover: Rob Matson's first meteorite find, Silver Dry Lake 001, where it was found 27 May 2000 at Silver Dry Lake north of Baker, California. It has been classified as an L4 ordinary chondrite, and "Looks a little bit like the head of a rhinoceros," he says. A handheld GPS device provides scale. See below for news from Rob Matson's astronomical archive sleuthing.

News briefs – panel 1/1 Major News for 27 April 2004 back top next  
News briefs

Meteor news:  Further to the Associated Press report yesterday about an unusual space-weathered lunar meteorite, BBC has an article today, "Scientists find new Moon mineral," and USA Today's article, "Long-predicted moon mineral named for researcher" from yesterday links to a scientific reference (252Kb PDF) by Mahesh Anand, et al.. It explains that meteorite Dhofar 280, an April 2001 Oman find, has been found to have small bits of iron and silicon in combinations that may have resulted from vaporization of lunar surface materials caused by micrometeorite impacts.

See also an Astrobiology Magazine article today, "Moon Meteor Truly Extraterrestrial."

Spitzer news:  The Spitzer Science Center today announced "the release of the IRAC FLS [First Look Survey] data, for all three components (Extragalactic, Galactic, and Ecliptic)." This is a step toward putting Spitzer Space Telescope MIPS data into the public archive that opens next month.

Archive sleuthing:  Yesterday's MPEC 2004-H76 announcing the discovery of Edgeworth-Kuiper Belt object 2004 EW95 was followed less than four hours later by MPEC 2004-H77, which reported that this object had been located in archived images from NEAT's Mt. Palomar telescope from March 12th and 1, 2, 13, and 15 April. Rob Matson told A/CC that, when he reported nine positions, he was informed by the Minor Planet Center that only the earliest two were new, as someone else had already reported the others. That turned out to be Reiner Stoss, and measurements from Krisztian Sarneczky were also acknowledged.

2004 EW95 was first spotted by Arianna Gleason and Jeff Larsen with the Spacewatch 0.9m telescope in Arizona March 13th, and was confirmed on 19, 23, and 24 April with the Spacewatch 1.8m telescope. The second MPEC has a note from Brian Marsden that EW95 is in 2:3 resonance with Neptune and can come within 9 AU of Uranus. From its preliminary calculation of absolute magnitude (brightness), 2004 EW95 may be on the order of 160 km. (100 miles) wide.

Rob Matson also hunts meteorites — see above.

Risk monitoring - panel 1/2 Major News for 27 April 2004 back top next  
Risk monitoring 27 April

The Tuesday Daily Orbit Update MPEC (DOU) reports observation of 2004 HE12 from the 2.5m Isaac Newton Telescope on La Palma in the Canary Islands Sunday night, and today both NEODyS and JPL removed all impact solutions for this object, which is estimated at a bit more than 600 meters/yards wide.

The only other object in today's DOU that is listed by both risk monitors is 2004 HK33, reported from Mt. John Observatory in New Zealand Sunday. Today NEODyS and JPL very slightly raised their risk assessments for this object, estimated at more than a kilometer wide.

2004 HW, also estimated at larger than a kilometer, is reported from Mt. John Sunday, and today NEODyS slightly raised its low risk ratings.

And yet another kilometer-size asteroid, 2004 GA1, is in the DOU from LINEAR in New Mexico yesterday morning. Today JPL very slightly raised its single-solution assessment.

more risk monitoring >>

Summary Risk Table - sources checked at 2159 UTC, 27 Apr

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 HZ NEODyS 4/262023-207617-2.61-2.6506.672
JPL 4/262023-206410-2.68-2.7206.672
 2004 HW NEODyS 4/272016-20564-5.08-5.4406.891
JPL 4/24R E M O V E D
 2004 HQ1JPL 4/26R E M O V E D
 NEODyS 4/262065-20793-6.27-6.3306.695
 2004 HMJPL 4/272101-21042-5.01-5.0109.984
 2004 HK33 NEODyS 4/272010-208025-1.99-2.3704.208
JPL 4/272019-210233-1.87-2.3704.208
 2004 HE12JPL 4/27R E M O V E D
NEODyS 4/27R E M O V E D
 2004 HD2JPL 4/252087-20871-5.56-5.5604.124
 2004 GE2JPL 4/242100-21001-6.02-6.02011.811
 2004 GA1JPL 4/272083-20831-3.82-3.82014.710
NEODyS 4/19R E M O V E D
VI = count of "virtual impactors" (impact solutions)
See A/CC's Consolidated Risk Tables for more and maybe
  newer details, and check the monitors' links for latest info.
Note that only objects recently in view are shown here.
Risk monitoring - panel 2/2 Major News for 27 April 2004 back top next  

<< continued from panel 1

Finally, small object 2004 HM is reported in the DOU from LINEAR yesterday morning, and today JPL added a second impact solution and slightly raised its low and far-off risk ratings.

Among the four active concerns not reported in the DOU, the Minor Planet Center Last Observations page is showing that 2004 HD2 was caught this morning by JPL's Table Mountain Observatory in southern California.

Update:  JPL has reposted 2003 UQ25 with one very low rated impact solution in the year 2093. This small object was previously listed with solutions from the day of its discovery announcement last October 24th until November 3rd. Additional October observations were reported in February.

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