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

Today's issue status: done & updated

• News briefs – radar news & comet tails
  panel 2 – bits & pieces
• Risk monitoring

Cover: This color image of C/2004 F4 (Bradfield) is from Wednesday morning by Rent-a-Scope proprietor Arnie Rosner, who was observing from home in southern California operating a 0.3m Takahashi Mewlon telescope at New Mexico Skies on a robotic Paramount GT1100s mount with FLI IMG1024 Dream Machine CCD camera.

Radar news:  The Friday Daily Orbit Update MPEC carries recent radar observations of four objects by Arecibo in Puerto Rico: 1999 DJ4 on 14 April, 2001 US16 on 28-29 April, 2004 HX53 on 30 April and 1 May, and 2003 YT1 on 1-2 May. All have minimum orbit intersection distances (MOIDs) with Earth well within the 0.05 AU definition of “potentially hazardous.” 2001 US16 is scheduled for further radar observation through Sunday at Goldstone in southern California. The largest of these is 2003 YT1, judged from its brightness to be on the order of 2 km (1.2 miles) wide, and the radar pages show that it has been found to be binary. (The 2003 YT1 radar planning page noted that an extra “dip” in YT1's lightcurve from ground-based photometry might “indicate the presence of a companion.”) On the other end of the size spectrum, 2004 HX53 is estimated from brightness to be about 80 meters/yards wide.

Comet tails:  Astronomy.com has an article from yesterday showing how to view comets C/2002 T7 (LINEAR) and C/2001 Q4 (NEAT). The latter is at its closest to Earth today (0.321 AU, more than 125 times the distance to the Moon), but not yet at its brightest.

Terry Lovejoy told the Comets Mailing List today about an image of C/2001 Q4 made last night that shows “what appears to be a faint type III tail . . . lagging back along the comet's trajectory,” but also “appears to be green and not yellow [therefore] clearly not” type III.

Also told to the Comets-ML today was that Dennis Persyk had posted to his new images page an image of C/2004 F4 (Bradfield) from May 3rd that had been reprocessed to better show “a 1.5 arc minute antitail.” (See the "cover" above for a C/2004 F4 image from May 5th.)

more news briefs >>

<< continued from panel 1

Bits & pieces:  The Virginian-Pilot has an article today about deep drilling being done to study the Chesapeake Bay impact crater “56 miles across and 1.2 miles deep, centered on Cape Charles” that was made “35 million years ago” when the area was a “shallow sea.”

For more about that work, see the U.S. Geological Survey Chesapeake Bay Crater pages, and a January 2004 GeoTimes article, “Coring the Chesapeake Bay Impact Crater.”

MSNBC has a report today, “NASA plans contests for space feats,” about a 15-16 June Centennial Challenges workshop in Washington, D.C. “aimed at devising the initial bargain-basement challenges” for the private sector such as, possibly, “Build a spacecraft that can put a 22-pound payload on the moon, or perhaps even bring samples back from an asteroid or one of Mars' moons.”

The Honolulu Advertiser tells today, “Planetary satellites get closer look here,” that, in “research published in the April 20 issue of The Astrophysical

Journal, [Tommy Grav and Matthew J. Holman] reported that infrared observations of the surface colors of [irregular Jupiter and Saturn] satellites last year revealed they can be grouped into families with common ‘ancestry’ [and] may be pieces of asteroid-like objects that were captured by the gravitational pull of Jupiter and Saturn about 4.5 billion years ago.” The preprint is available as a 147Kb PDF.

Risk monitoring 7 May

There is no news to report from the Friday Daily Orbit Update MPEC with regard to objects listed with impact solutions, but the Minor Planet Center Last Observation page is showing that Tenagra II Observatory in Arizona caught 2004 HQ1 this morning.