Meteor news:  Nature Science Update has an item dated tomorrow, "Dust explains shooting stars' twin streaks." The article, which tells that lidar observation suggests one trail is gas and the other dust, has a bad link to a December 6th article in Geophysical Research Letters, "A new explanation of persistent double meteor trains" by Michael Kelley et al., and shows a picture of a comet to illustrate "meteor trails."

Numbers & names:  The Central Bureau for Astronomical Telegrams is showing that comet 2001 RG100 = 1979 O1 has been numbered as 158P/Kowal-LINEAR. See A/CC's report about 2001 RG100's recent identification as a comet, and news about its correlation with C/1979 O1.

Geminids:  We are now in the period of the annual Geminid Meteor Shower. Gary Kronk is predicting maximum activity at 2045 UT on the 13th and 1510 UT on the 14th. Some meteor showers are associated with particular comets, but the Geminids are associated with an object that classified as an asteroid, although suspected to be an inactive comet, 3200 Phaethon [link|alt].

3200 Phaethon's orbit and position on December 14th as displayed with EasySky (ecliptic grid at 0.02 AU).

3200 Phaethon is a potentially hazardous object that can come close to both Earth and Venus. NEODyS lists some recent and future Earth flybys, including one in 2093 at just over 7.7 lunar distances. That's quite close enough for something with a width estimated at four to seven kilometers (2.5 to 4.4 miles). It is in view now for advanced amateur observers, presently out beyond the orbit of Mars.

See a Sky & Telescope article for more about the Geminids.

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Precovery:  MPEC 2003-X39 announced overnight that 2003 WC25 has been found by Reiner Stoss in NEAT/Palomar images from April last year, and in plate scans from the same telescope of 6 October 1989. As A/CC noted at the time, 2003 WC25 was one of three kilometer-size NEOs discovered by LINEAR during 20-21 November.

Tsunami news:  NOAA Magazine reported yesterday the first successful use of the DART system (Deep-ocean Assessment and Reporting of Tsunamis) involving "a 7.5 earthquake in the Aleutian Islands" on November 17th (event data). A similar event in 1986 caused what turned out to be an unnecessary emergency evacuation of some Hawaiian coastal areas at great cost and uproar, but this time the DART data allowed a decision not to evacuate. The article notes that "Most tsunamis are generated by earthquakes, but they may also be caused by volcanic eruptions, landslides, undersea slumps or meteor impacts." (More DART info.)

Voyager 1:  The University of Iowa has a news release from yesterday about Don Gurnett and his Space Plasma Wave Group and the search for Solar System boundaries.

“"Using the Voyager 1 plasma wave instrument, we started detecting a strong radio emission event in November 2002 that is continuing to the present time. . .  The time delay between the solar flare activity and the onset of the radio emission indicates the heliopause is located about 153 to 158 AU (14.3 to 14.7 billion miles) from the sun," Gurnett says. "From computer simulations that give the ratio of the radial distance to the termination shock to the radial distance to the heliopause, the distance to the termination shock can also be calculated and is estimated to be about 101 to 118 AU." ”

See other recent news from Voyager 1.

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Risk monitoring 9 Dec.

The Tuesday Daily Orbit Upate MPEC (DOU) has observations of 2003 WW26 from last night from La Palma, and today NEODyS eliminated its last impact solutions for this small object, estimated at roughly 120 meter/yards wide, while JPL is down to one very low-rated solution.

The DOU also has observations 2003 WG from Church Stretton Observatory Sunday night and Linz Observatory last night. Today JPL eliminated its last impact solution for this half-kilometer object.

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