Tuesday20 April 200411:54pm MDT2004-04-21 UTC 0554 back top next  
C/2004 F4 (Bradfield) from ESA/NASA SOHO

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


Today's issue status: done & updated 2x
yesterdayApriltomorrowIndex
  • News briefs – comet news plus bits & pieces
  • Risk monitoring – JPL has posted 2004 HQ1 & 2004 HZ + NEODyS has posted 2004 HW

Cover: One of the more spectacular views of C/2004 F4 (Bradfield) from yesterday available over the Internet in near real time from the SOHO LASCO C3 coronagraph, when it was about 49 hours past the estimated closest approach to the Sun. The main image is shown cropped at 50% original size, and it and the animation frames are courtesy of the NASA/ESA SOHO mission. Update MPEC 2004-H37 today puts perihelion about three hours later and a bit closer to the Sun than first first predicted.

News briefs – panel 1/1 Major News for 20 April 2004 back top next  
News briefs

Comet news:  "Elvis has left the building" (see images and more info above) with now just the long tail of comet C/2004 F4 (Bradfield) still in view from the SOHO LASCO C3 coronagraph. One can only wonder at the surprise of the SOHO regulars, who hunt small dim Sun-diving comets, if C/2004 F4 had heaved into view without warning from William Bradfield or some other southern Hemisphere early-morning sky watcher.

There is no evidence yet for fading or disruption, so the big question is how visible C/2004 F4 will become in the next few days (see a BBC item today and a sky chart at SpaceWeather.com). Maik Meyer tells A/CC that it may be possible for an experienced observer to see this comet soon, even now, but it "will be no easy object."

Two other comets that are beginning to put on what's hoped will be their best shows, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), are the subject of a new page posted by Gianluca Masi and Franco Mallia for images they made remotely with the Southern

Telescopes in Education (SoTIE) 14" telescope at Las Campanas in Chile. Among some great imagery, note C/2002 T7 from April 17th at page bottom showing an anti-tail and detailed streaming main tail.

Bits & pieces:  The Namibian has an article at AllAfrica.com today, "Meteorite Smuggling Case Withdrawn." It mentions that "minerals dealer Walter Horst" had been charged with being in possession of a stolen "296 kg" meteorite and separately for trying to export four meteorites. In Namibia, it says, meteorites "are protected by law and may not be moved from where they are found or exported," and reports that "Meteorites from Gibeon [in the south] are being advertised for sale on collectors' websites on the Internet — all illegally, since export is forbidden."

The ESA Rosetta mission has a status report from yesterday, "Second Lander Commissioning Slot" telling of a second pass at commissioning the Rosetta lander that was routine and successful but hints at "a few" glitches.

Risk monitoring - panel 1/1 Major News for 20 April 2004 back top next  
Risk monitoring 20 April

Of five NEOs discovered from Australia since March 29th, four have minimum Earth orbit intersection distances (MOIDs) that would classify them as potentially hazardous, except that two are too small for PHA status, while the other two are both kilometer size, and are both presently listed at right with virtual impactors (VIs). 2004 HW is the newest. It was announced yesterday in MPEC 2004-H32 as discovered Sunday and confirmed Monday UT by the Siding Spring Survey is Australia. Yesterday evening in Pasadena, after midnight UT, this object was posted by JPL.

The Tuesday Daily Orbit Update MPEC has no new observations for 2004 HW, but has all the rest, which presently are listed by only JPL with a very few low-rated impact solutions beyond the NEODyS 2080 time horizon. The other Australian discovery, 2004 GA1, was reported from Hunters Hill Observatory Sunday in southeastern Australia. Hunters Hill also reported 2004 GE2 from that day, as did LONEOS on the 15th in Arizona. And both GE2 and 2004 HM were reported from early yesterday by Pla D'Arguines Observatory

Summary Risk Table - sources checked at 0539 UTC, 21 Apr

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 HZJPL 4/202007-2102486-3.69-4.0901.039
 2004 HW NEODyS 4/202009-207719-2.62-2.8801.053
JPL 4/202008-2103271-1.87-2.4501.053
 2004 HQ1JPL 4/212058-210334-4.87-5.3101.039
 2004 HMJPL 4/202101-21042-5.35-5.3502.740
 2004 GE2JPL 4/202100-21001-5.15-5.1506.817
 2004 GA1JPL 4/202083-20831-4.06-4.0607.391
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.

in Spain and Great Shefford Observatory in England. Today JPL very slightly raised its 2004 HM risk ratings and slightly lowered its assessments for the other two.

Update:  NEODyS has now posted 2004 HW. And JPL has posted small object 2004 HZ, announced in MPEC 2004-H34, as discovered yesterday morning by LINEAR and confirmed last night by Observatorio Astronomico de Mallorca and early today by Desert Moon and Sabino Canyon observatories.

Late news:  JPL has posted 2004 HQ1.

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