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

Today's issue status: done

• Small objects – report for 1-7 March
  Small object observation summary
• News briefs – recovery & Rosetta
• Risk monitoring

Cover: Not seen since August 6th, tiny 2003 DW10 remains on the JPL and NEODyS risk pages, and last week JPL very slightly changed its assessment. It was discovered on Feburary 26th and John Rogers at Camarillo Observatory in southern California caught it on March 2nd. He wrote at the time: At visual magnitude 17.1, 2003 DW10 was 0.00607 astronomical units (2.3 lunar distances) from the Earth, moving across the sky at 26° per day, when this 30-sec. exposure was taken. The telescope tracked on the asteroid's motion, so it appears as a dot near the image center, while background stars are streaked.

Discovery & follow-up 1-7 March
During this past week with the bright Moon, and with the NEO surveys and other observers in the U.S. Southwest clouded out much of the time, no small object discoveries were announced, and only two small objects were tracked. Belated observations from February and last August were reported for two more, and archive work was reported for another three.

"Small" means with absolute magnitude (brightness) of H greater than 22.0, which converts roughly to diameters of around or less than 135 meters/yards. The small object watched most closely this last week was 2004 CE39, which was announced at H=22.4 but is currently calculated as being a bit larger by the Minor Planet Center (H=21.5) and JPL (H=21.39) — perhaps about 180 meters wide.

The JPL NEO Program restated risk assessments last week for seven objects not under current observation, and all seven are small objects. Two, 1994 WR12 and 2001 SB170, are put by JPL at about

110 meters wide, 2003 LN6 40 meters, 2003 DW10 20 meters (see cover above), and three at 10 meters: 2003 UM3, 2003 WT153, and 2003 YS70.

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Notes: Diameters in the following observation summary table are rough best estimates from a standard but very inexact H-to-size formula using H (absolute magnitude) from the JPL NEO Orbital Elements page, source also for Earth MOID (minimum orbital intersection). Other planetary MOIDs are from Lowell Observatory. Current Minor Planet Center H is also given, along with the original H from each object's discovery MPEC. Priorities and visibilities are from the European Spaceguard Central Node (SCN).

Recovery:  MPEC 2004-E25 today reports that Jim Young with the 0.6m telescope at JPL's Table Mountain Observatory in southern California recovered PHO 2002 EW yesterday morning and this morning. Discovered by LINEAR on 5 March 2002, this object is roughly estimated at 230 meters/yards wide.

Rosetta:  SpaceRef.com yesterday posted the first Rosetta status report with launch and trajectory details, switching on spacecraft systems, and this:

“ The launch locks of the Lander Philae have been released successfully at the end of the first ground station pass [on March 2nd]. Philae now remains firmly attached to the spacecraft by the cruise latches until its release at the comet. ”

Risk monitoring 7 March

For the first time since last November 18th, there are no objects under active observation that have impact solutions.