Thursday19 February 200411:47pm MST2004-02-20 UTC 0647 back top next  

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


Today's issue status: done, updated
yesterdayFebruarytomorrowIndex
Philae lander
in blue circle

Cover: Launch is scheduled one week from today for the Rosetta spacecraft, seen here from above as it was mated to the nose of its Ariane 5 launcher on Monday. The shiny side of the spacecraft is a folded solar panel. Stuffed into the adjacent side is the octagonal Philae comet lander with one folded leg in view. Image ©Copyright 2004 ESA-CNES-Arianespace. More news below.

Massive discovery – part 1/2 Major News for 19 Feb. 2004 back top next  
Massive discovery

0857 UTC report MPEC 2004-D09 announced 2004 DW very early today UT with a preliminary orbit calculation that has this as an Edgeworth-Kuiper Belt object of the Cubewano persuasion (not in resonance with Neptune [see new next day conclusion–Ed.]), and with absolute magnitude H=2.5. If this holds, the object is in the range of 840 to 1,880 km. (520-1,170 miles) wide according to a standard but very inexact formula. Thus it is probably larger than any Main Belt asteroid and could be a contender for the title of 3 known minor object, if one doesn't count Pluto and its moon Charon. See David Jewitt's 1000 km Scale KBOs page for comparisons and an explanation of the difficulties in gauging size for such objects.

Discovery was Tuesday morning with NEAT's Mt. Palomar 1.2m telescope in southern California, followed up early yesterday by the Starkenburg Observatory team with the 1.52m telescope at Calar Alto in Spain (see news yesterday), and by Jim Young with the Table Mountain Observatory 0.6m telescope in southern California.

2004 DW

1714 UTC update
From Felix Hormuth, Martin Buchmann & Matthias Busch at Calar Alto: [This] is an image of 2004 DW obtained on 2004 February 18, 04:00:47 UTC with 30-sec. integration time. The telescope is the Spanish 1.52m reflector at Calar Alto equipped with a Tektronics TEK1024 CCD binned 2 by 2, giving a pixel scale of 0.81 arcsec. Weather conditions were moderate with high clouds and seeing no better than 1.2 arcsec.

more about 2004 DW >>

Massive discovery – part 2/2 Major News for 19 Feb. 2004 back top next  

<< continued from part 1

Updates:  Chad Trujillo has posted a Frequently Asked Questions About 2004 DW page that tells it was not the NEAT team that discovered 2004 DW, but rather himself with Mike Brown and David Rabinowitz using images from the Mt. Palomar telescope also used by NEAT. He says, "Initial indications are that [2004 DW] may be over half the diameter of Pluto, larger than Quaoar, and 2.4 billion kilometers (1.5 billion miles) further away than Pluto. [It] is probably about 1600 km in diameter, larger than the 1250 km Quaoar."

MPEC 2004-D13 just after midnight UT reports a 2004 DW position from Mt. Palomar from December 3rd and a new observation from Irmtraut Observatory today.

At right: Orbit diagrams for the five largest known EKBOs according to David Jewitts' 1000 km Scale KBOs page, created from screen shots from EasySky, a planetarium program written by Matthias Busch, who is on the team that confirmed 2004 DW from Calar Alto.

News coverage elsewhere

EasySky screen shots showing
locations for the 5 largest known
EKBOs where they are today
Rosetta – part 1/1 Major News for 19 Feb. 2004 back top next  
Rosetta at one week to go

There are several news items that preview an epic voyage or update preparations for Rosetta's launch, now less than seven days away, early on February 26th. The Particle Physics and Astronomy Research Council (PPARC) Rosetta page was changed to show a new news release today, "UK Scientists Countdown to launch of Europes Comet Chaser Mission." That will be replaced in turn by something else, so we also note a more permanent copy at EurekAlert.

As the PPARC news release notes, there will be a live broadcast of the launch available on the Web, about which you can learn more at the European Space Agency ESA Television page. There are also a number of archived Rosetta video clips that A/CC readers will likely find interesting.

NASA has a news release today, "Spacecraft To Launch, Designed To Harpoon Cosmic Moby Dick," telling about its mission participation, along with JPL and the Southwest Research Institute, involving four instruments aboard the comet orbiter.

Rosetta fairing installation

Arianespace caption: In the upper level of the Final Assembly Building, technicians watch as the payload fairing is carefully lowered over Rosetta. The fairing will be jettisoned at approximately 3 minutes after liftoff, when Ariane 5 will be at an altitude of about 105 km. Image ©Copyright 2004 ESA-CNES-Arianespace.


The Arianespace launch kit page now links to a Rosetta launch kit 953Kb PDF. And an Arianspace Mission Update from yesterday tells about assembling and placing the fairing over the Rosetta spacecraft atop its Ariane 5 launcher. Today's "cover" picture above and news Tuesday show the mating with the launcher.

News briefs – part 1/1 Major News for 19 Feb. 2004 back top next  
News briefs

Stardust results:  The Stardust mission has posted a Stardust LPSC 2004 Abstracts page with a link to a 1.16Mb PDF file containing "Abstracts of the Stardust science results from the Comet Wild 2 encounter" that will be presented on 15 March at the Lunar and Planetary Science Conference (LPSC) near Houston, Texas. As the file's size indicates, it contains more than just bare abstracts for papers such as "Streaming Clumps Ejection Model and the Heterogeneous Inner Coma of Comet Wild 2."

Meteor news:  Arizona State University has a news release at EurekAlert today about journal Science article (Brevia: "Prebiotic Amino Acids as Asymmetric Catalysts" by Sandra Pizzarello and Arthur L. Weber). It considers issues such as why carbonaceous chondrite "meteorites contain over 70 amino acids [while a] mere 20 amino acids make up life's proteins."

The Friday Cowra Journal has more eyewitness reports of Tuesday's Australian fireball (news thread).

Call for observations:  As announced to the Comets Mailing List today, Charles Morris has posted to his JPL comet site a call for observations of comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) from Geraint Jones of Imperial College's instrument team on the Ulysses mission, and from Jack Brandt of the University of New Mexico. Amateur astronomers provide valuable scientific contributions in work such as this, and Greraint and Brandt note that "Observations of the ion or plasma tail of a comet can reveal the solar wind conditions in the comet's vicinity."

There was news last August about Ulysses and interstellar dust, and ESA has a February 9th news release, "Ulysses Catches Another Comet by the Tail":

In an article soon to appear in Astrophysical Journal Letters, the same Ulysses teams that identified [the tail of Hyakutake (C/1996 B2)] present evidence for one (and possibly two) new tail crossings. . .  The comets involved were McNaught-Hartley (C/1991 T1) and SOHO (C/2000 S5) [which] seemed to be at the wrong location for Ulysses to intercept their tails. By chance, a Coronal Mass Ejection moving away from the Sun enveloped both the comet and the spacecraft, carrying the cometary material to Ulysses. 
Risk monitoring - part 1/1 Major News for 19 Feb. 2004 back top next  
Risk monitoring 19 Feb.

NEODyS has joined JPL in posting 2004 DC and also today has posted 2004 DD. The latter was announced yesterday in MPEC 2004-D07 as discovered Tuesday morning by Arianna Gleason with the Spacewatch 0.9m telescope in Arizona and confirmed over the next night by KLENOT in the Czech Republic, the Starkenburg Observatory team at Calar Alto in Spain, and Arianna Gleason with the Spacewatch 1.8m telescope. From its brightness (JPL H=17.89), this object is roughly estimated at 895 meters/yards wide.

None of the objects listed with impact solutions and currently in view were reported in the Thursday Daily Orbit Update MPEC.

Summary Risk Table - sources checked at 0637 UTC, 20 Feb

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 DD NEODyS 2/192012-207417-4.97-5.3500.832
 2004 DC NEODyS 2/192006-207985-2.51-2.8502.013
JPL 2/182006-2103263-2.29-2.7302.013
 2004 BG121 NEODyS 2/142005-2080123-3.65-3.9400.934
JPL 2/13R 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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