Thursday8 January 200410:59pm MST2004-01-09 UTC 0559 back top next  

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

Today's issue status: done
  • News briefs
    – Stardust images, 2004 AD & Hayabusa
    2P/Encke at Mercury by Piero Sicoli
    Spanish fireball update by Marco Langbroek
  • Risk monitoring

Cover image: Tiny 2004 AD shown in eleven frames stacked in Astrometrica by Robert Hutsebaut from his confirmation observations on January 5th UT (MPEC 2004-A23). It was just after 7am where he was in Belgium, and before midnight at the Rent-a-scope 0.3m telescope he was operating at New Mexico Skies Observatory (more info). He notes that the object then was "33° from the nearly full Moon." The object's motion was so fast that background stars appear as "pearl strings." See today's 2004 AD news below.

News briefs – part 1/2 Major News for 8 Jan. 2004 back top next  
News briefs

Stardust:  Today a 290Kb GIF animation was posted to the Stardust mission home page, marking the first release of additional frames beyond the two higher-resolution images released Friday and Tuesday. Hints of coma and jets can be seen in some frames. Ron Baalke at JPL told the told the Minor Planet Mailing list (MPML) today that, while the original frames are at 1024x1024 resolution, this animation is at 300x300 "to get something out [to] the public quickly, but not in too much detail to allow the Stardust scientists to submit their science papers without being scooped." Under NASA guidelines the Stardust data and imagery can be held as proprietary for up to six months.

BBC has a report from Tuesday's news today, "Comet dust packed away for Earth," as does today, "Stardust survives comet encounter." The Brattleboro, Vermont Reformer has a local take today, "At Omega, the sky is the goal, not the limit," telling about Omega Optical's part in the Mars rover and Stardust missions with its optical filters.

2P/Encke at Mercury   by Piero Sicoli

At Sormano Astronomical Observatory we have completed computations for an update to our List of Planetary Close Encounters (PCEL) for Mercury, Venus, and Mars for the next two centuries. The aim, besides checking for possible collisions, is to obtain information about the frequency of such events. The inclusion of some periodic comets in the list led to the discovery that 2P/Encke [link|alt] will have a close approach to Mercury on 18 November 2013, at 0.0250 AU (just under ten lunar distances).

Piero Sicoli notes that Encke's passage might represent an observation opportunity for a spacecraft in Mercury orbit, and earlier planning for ESA BepiColombo would have had the mission ending around that time, but its schedule now has arrival at the end of 2014. NASA/JHUAPL Messenger is to launch this June and go into Mercury orbit in July 2009 for a one-year mission ending around the time of a less favorable 2P/Encke passage, but Messenger seems unlikely to survive the harsh solar environment until Encke's close passage in late 2013.–Ed.

[News briefs continued]

News briefs – part 2/2 Major News for 8 Jan. 2004 back top next  

  [continued from part 1]

2004 AD:  As reported briefly yesterday ("Radar news"), Arecibo urgently requested astrometry to help better locate 2004 AD, a tiny object that is the subject of today's "cover" above. Mike Nolan at Arecibo tells A/CC that "More observations did come in, but they essentially confirmed the orbit solution that I was using, so I didn't observe it last night. The weak detection and narrow signal that we observed suggest that it is a bit smaller than predicted, perhaps of order 15m."

Today's Daily Orbit Update MPEC reported this radar work as well as optical observing from Siding Spring and Tenagra II observatories, all from yesterday, and the Observatorio Astronomico de Mallorca (OAM) caught it on both sides of midnight UT.

Hayabusa:  SpaceDaily has an article today, "In Wake Of Stardust Flyby, Hayabusa Aims For Asteroid Sample Return," summing up Japan's MUSES-C Hayabusa mission to date.

Spanish fireball update   by Marco Langbroek

In a message on the MeteorObs mailing list overnight, Victor Ruiz pointed out that the Moon is visible in the January 4th Leon fireball video. It is not well apparent in the RealPlayer version, but very evident in an animated GIF version at

This indeed is the Moon, visible just left of the sunlit appartment building. At Leon, the Moon was located at azimuth 78°, at an altitude of 22°, on 4 January 1645 UTC. This therefore confirms my conclusion that the video is looking northeast (actually it is east-northeast). This also confirms that the fireball was not travelling in a NW-SE trajectory (it should move from the left to the right then, but it goes opposite), and is not a member of the Quadrantid stream. It also suggests that the location of the fireball must be sought near the Asturia-Spanish Basque province borders, and current recovery efforts (if indeed something is to be recovered at all) are focusing on the wrong area.

It also again underlines that the fires reported at several locations are unrelated to the fireball.

This report continues a news thread from January 6th, and Langbroek's report at the Dutch Meteor Society now explains why returning space junk can be ruled out.–Ed.

Risk monitoring - part 1/1 Major News for 8 Jan. 2004 back top next  
Risk monitoring 8 Jan.

The Thursday Daily Orbit Update MPEC carries observations of 2004 AF from Tenagra II Observatory yesterday morning in Arizona and last night from Jurassien-Vicques Observatory in Switzerland. Today NEODyS cut its impact solution count from 88 to 74, and JPL shed a few solutions and slightly raised its overall risk assessment for this kilometer-plus object.

Update:  This afternoon in Pasadena, JPL updated its 2003 YS70 assessment based apparently on the existing observation set. The impact solution count went from six to one, and the already low overall risk ratings were further lowered slightly. This tiny object is now out of view, and wasn't reported seen after December 27th.

Later update:  This evening in Pasadena, JPL removed 2003 YD45. The Minor Planet Center's Last Observation page is showing that YD45 was caught by La Palma in the Canary Islands yesterday (the 7th).

Summary Risk Table - sources checked at 0544 UTC, 9 Jan




 2004 AF NEODyS 1/82008-207974-2.86-3.4002.582
JPL 1/82008-209817-3.20-3.2702.582
 2003 YS70JPL 1/92075-20751-8.36-8.3604.992
 NEODyS 12/282057-20808-7.72-8.1504.992
 2003 YD45JPL 1/9R E M O V E D
NEODyS 12/30R 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.
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