Thursday18 March 20044:26pm MST2004-03-18 UTC 2326 back top next  

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


Today's issue status: done
yesterdayMarchtomorrowIndex

Cover: Earth's busy sky was caught by Robert Hutsebaut on his lunch hour in Belgium using a Rent-a-scope telescope at New Mexico Skies. This is a 300-second exposure centered on 1121:33 UTC (4:21am Mountain Time), with apparently two satellites crossing the image as long trails, while the Earth-buzzing 2004 FH finishes the skywriting job, at that point moving 87"/minute toward 243.4°. See below for more about this developing story.

Asteroids as spectator sport – part 1/1 Major News for 18 March 2004 back top next  
Asteroids as spectator sport

Just to get started with today's reporting, here are some links. The Minor Planet Center has issued update MPEC 2004-F26 at 1514 UTC (10:14 EST) with a comment that, "2004 FH will approach the earth to 0.00033 AU on March 18.92 UT." That is 0.1289 lunar distances at about 2200 UTC (5pm EST) today.

A/CC is receiving images for publication, with more to be shown here. Robert Hutsebaut's this morning seems to symbolically represent the actuality of Earth's busy sky and cosmic neighborhood, where small asteroids roam close by, usually unseen, so his got today's "cover" spot above. We will also link to other site's imagery of this event, and thanks to Milos Tichy at KLENOT for alerting A/CC to the 2004 FH page there showing the very first confirming images of this object following LINEAR's discovery. See A/CC's report yesterday evening for the details of the discovery and confirmation sequence.

JPL has updated its risk assessment for 2004 FH once today, and is expected to update at least once

more before the day is out. This is only about future Earth encounters by this small object (JPL puts the size at 20 meters/yards wide), beginning with the year 2038, and with an overall low risk assessment. Because this flyby is so close, 2004 FH's orbit is changing while it is being watched, so calculating its future path is a "moving target" in more than one sense.

Update: JPL has changed its 2004 FH risk assessment and NEODyS has posted 2004 FH (see below).

Arecibo has scheduled observation of 2004 FH by radar for tomorrow and Saturday.

The JPL NEO Program Office issued a news item overnight and updated today:

[2004 FH] will pass just 43,000 km (26,500 miles, or about 3.4 Earth diameters) above the Earth's surface on March 18th at 5:08 PM EST (2:08 PM PST, 22:08 UTC) . . . over the South Atlantic Ocean. 

It notes that 2004 FH will be inside the Moon's orbit for a period of 31 hours, and will be visible with binoculars "from areas of Europe, Asia and most of the Southern Hemisphere."

more about 2004 FH >>

Asteroids as spectator sport – part 2/2 Major News for 18 March 2004 back top next  

2004 FH news coverage
Here are links to news today in the space and astronomy news media. The first two stories include links to information on how to watch this event with binoculars in some parts of the world, while it will be a target in North America suitable only for experienced observers:

The general news media picked up the 2004 FH story beginning on the U.S. West Coast at just after 9pm PST yesterday (0500 UTC this morning), when the San Diego Union-Tribune and others published an Associated Press wire story based on the JPL NEOP announcement, with headlines such as, "NASA: 100-foot asteroid to make record, but harmless, pass by Earth." One nitpick is that this report says 2004 FH was discovered "late Monday." It was first seen at 0817 UTC Tuesday morning, 12:17am MST local time.

2004 FH 2004 March 2004 flyby animation 
by Pasquale Tricarico, created in ORSA

See a 368Kb animation by Pasquale Tricarico showing today's flyby from the perspective of riding the asteroid, as if the observer was always facing the Earth (rather than rapidly rotating, as would actually be the case). This frame is just past the closest approach above the south Atlantic Ocean.

There's more. See tomorrow's cover, "2004 FH as meteor event," and 2004 FH news coverage.

News briefs – part 1/1 Major News for 18 March 2004 back top next  
News briefs

Lunar comet impact?  Astronomy.com has a report from yesterday from the 35th Lunar and Planetary Science Conference (LPSC) now underway in Texas. It tells of a presentation by Patrick Pinet et al. about "a curious feature named Reiner Gamma [in] western Oceanus Procellarum on the Moon." They think it can be explained by the impact of a disrupted comet "perhaps 10 million years" ago.

Stardust news:  The Stardust mission has posted a news release dated yesterday, "Composite and Stereo Images of Comet Wild 2 ." And Astronomy.com has a report today based on principal investigator David Brownlee's presentation at the LPSC 2004 (see item at left).

Risk monitoring - part 1/1 Major News for 18 March 2004 back top next  
Risk monitoring 18 March

The Thursday Daily Orbit Update MPEC (DOU) has many observations of 2004 FH, and that was followed by update MPEC 2004-F26 with even more positions. JPL has updated its 2004 FH risk assessment based on the DOU, cutting its impact solution count from 19 to 11, with now the first solution in 2038 instead of 2031, and slightly lowered its already low overall risk assessment. It also reduced its diameter estimate from 30 to 20 meters.


Update #1:  JPL has issued a new 2004 FH risk assessment incorporating data from the second MPEC of today with observations, and is now down to just one very low rated impact solution in 2073.


Update #2:  NEODyS has now posted 2004 FH with an assessment similar to JPL's latest.

Summary Risk Table - sources checked at 2358 UTC, 18 Mar

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 FH NEODyS 3/182073-20731-6.77-6.7702.193
JPL 3/182073-20731-6.88-6.8802.193
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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