March 2003 Asteroid/Comet News

1 March 2003

Newly discovered 2003 DH6 came to within about 6.2 lunar distances of Earth today. JPL says this object, which was discovered on 23 Feb. by Bruce Koehn at LONEOS, is between 44 and 99 meters/yards wide.

The JPL NEO Program today added to its Palermo Technical Impact Hazard Scale page an explanation of "cumulative Palermo Scale":

The cumulative Palermo Scale value reflects the seriousness of the entirety of detected potential collision solutions. It is the base-10 logarithm of the sum of the individual relative risk values. PS_cum = log₁₀ (10^PS1 + 10^PS2 + 10^PS3 + ...)

Site news: On 5 March 2003 we inaugurated the A/CC Meeting Calendar for events related to minor object science — from astronomy to mission design. On the list are several meetings around the world aimed specifically at bringing together professional and amateur astronomers to share info about minor objects.

Astronomy.com on 7 March has an article about the discovery of comet C/2002 Y1 (Juels-Holvorcem) and telling about viewing prospects for northern observers.

79P/du Toit-Hartley was recovered by Los Molinos Observatory in Uruguay according to MPEC 2003-E32 of the 8th, with observations reported from 4-5 March.

A Novosti wire service report of 9 March: "Irkutsk scientists intend to go to taiga to study a large meteorite." It says that researchers want to reach the impact location before Spring begins in the Vitim River basin. This picks up last September's fireball story, which broke in early October.

Robert Macmillan at Spacewatch confirms that the first discovery with the newly refurbished Steward Observatory 0.9m telescope is NEO 2003 EN16, found on 8 March and announced on the 10th in MPEC 2003-E38. The next day, another NEO discovered with this telescope, 2003 EZ16, was announced in MPEC 2003-E41.
      It would take 11 NEO discoveries to get the first classifed by the Minor Planet Center as potentially hazardous. 2003 JC13 was first spotted on May 7th by Mike Read and was announced in MPEC 2003-J41. Meanwhile, on April 23rd, the telescope celebrated the 80th anniversary of its formal dedication.

A bit of a dry spell in comet discoveries was broken on the 12. MPEC 2003-E47 announced P/2003 CP7 (LINEAR-NEAT), with observations reported going back to February 1st at LINEAR and March 10th at NEAT's Palomar telescope, with some in between at LONEOS. P/2003 CP7 lives its life between Mars and Jupiter, calculated to come to perihelion on the 29th of next month at 3.018 AU — nearly twice the average distance of Mars from the Sun. At its furthest reach of 5.017 AU, CP7 approaches Jupiter's orbit.
      MPEC 2003-E48 announced another distant comet, C/2003 E1 (NEAT), with perihelion initially calculated at 2.95 AU just over a year from now, next March 13th. It was first spotted with NEAT's Palomar telescope on the 9th.

Sky & Telescope had an article telling how 4 Vesta was coming into good view, even naked-eye visible around March 27th for those with good seeing conditions. There is a nice piece 15 March on VOANews.com about NEO observer Ron Dyvig and his Badlands Observatory in South Dakota, where the town put an on/off switch on his nearest streetlight.

Coming out of the Lunar and Planetary Science Conference (LPSC), underway 17-21 March near Houston, Texas, is a University of Arizona news release today about how planetary scientist H. Jay Melosh says an asteroid smaller than a kilometer wide would not cause catastrophic tsunami situations from an ocean impact. See also David Morrison's report posted 18 March about a 16 March tsunami hazard workshop. Astronomy.com had a 19 March article.       In the edition of Cambridge Conference Correspondence (CCC) dated 14 March, Ed Grondine reports about the number of papers scheduled for presentation at the conference about improving crater counts and counting methods.

The Minor Planet Center on 18 March updated its Discovery Circumstances page with 2,373 new asteroid numberings, now totalling 58,092. There are also 140 new namings from a diverse array of discoverers, from 6688 Donmccarthy (1981 ER17), discovered at Siding Spring by Schelte J. Bus, to 51895 Biblialexa (2001 QX33), discovered at Ondrejov Observatory by Petr Pravec and Peter Kusnirak. The latter is now the highest numbered object with a name. A sampling of other namings: 12818 Tomhanks (1996 GU8), 12820 Robinwilliams (1996 JN6), 15631 Dellorusso (2000 HT57), 16452 Goldfinger (1989 SE8), and 26887 Tokyogiants (1994 TO15).
      NASA/Goddard put out a 15 April news release about the naming of 14120 Espenak (1998 QJ54) for Fred Espenak, "a world-renowned authority on solar eclipse predictions." He has both official and personal eclipse sites.
      The previous new namings/numberings were announced on 20 Feb., and the next came on May 1st.

Sky and Telescope in a 20 March article, "Too Few Lunar Meteorites," tells of puzzlement over why more meteorites have been found from Mars than the Moon.

The second amateur-discovered NEO of 2003 was announced on 24 March in MPEC 2003-F28. 2003 FG was found yesterday by Desert Eagle Observatory, which a month ago picked up the first of the year, 2003 DN4.

A fireball was seen from Wisconsin, Michigan, Illinois, Indiana, and Ohio around local midnight 26-27 March, with numerous fragments falling over the southern Chicago area. An early estimate of the object's pre-entry width is one to two meters/yards. The University of Chicago put out a news release yesterday, "Meteorites shower Chicago's south suburbs." Space.com has an article today, "Meteor Showers Rocks on Midwestern Homes," and CNN today is carrying yesterday's AP wire story. Thanks to Bob Johnston for reporting a link to an article today in the Northwest Indiana Times, "Meteor showers rubble onto south suburbs."
      Astronomy.com has a 29 March report. Cambridge Conference Correspondence editions posted on 31 March with 27 March and 28 March dates have the texts from several news media accounts. See also reports from local TV stations WLS-TV and WMAQ-TV.
      The first report of scientific analysis came from Peter Brown in a 21 April article at Sky & Telescope. He says the fireball was caught on video and by infrasound (from Manitoba), and estimates that the original object, an L5 ordinary chondrite, was about two meters/yards wide.
      Updates:  See a National Geographic May 13th report about the ensuing sales of meteorite specimens, and about work by the Field Museum's Associate Curator of Meteoritics, Meenakshi Wadhwa. See also the museum's own page about the March event.
      The Chicago Star had an article August 10th (temporary URL) about one March meteorite going on display at the Field Museum. Since some area residents have kept pieces, the article reports advice from Wadhwa on how to care for them: The metal in meteorites tends to rust quickly, she said, so the rocks should be in a cool, dry place. People can keep moisture from getting to them by putting the rocks in a plastic bag, then putting that bag inside another plastic bag containing silica gel. "We store a lot of our meteorites that way."

The Daily Orbit Update MPEC for the 30th reported that NEO 1999 WK11 had been found on Siding Spring plates from 30 Sept. and 10 Oct. 1980. This object, which is on the order of a kilometer in diameter, was initially observed during only a two-week period in December 1999, but was picked up again last November.

MPEC 2003-F61 on 30 March announced 2003 FY6, which has an eccentric orbit of low inclination that lies mostly inside Earth's orbit, with perihelion at 0.307 (inside Mercury's orbit) and aphelion at 1.155 AU. This object was discovered on 29 March by Michael Van Ness at LONEOS and was followed up by nine other observatories through this morning.
      Also this day, MPEC 2003-F62 reported that Erich Meyer at Linz Observatory had recovered NEO 2000 SH8 on 28-29 March.

Fast rotator mostly inside Earth's Orbit

Jure Skvarc at Crni Vrh Observatory in Slovenia has bagged a very interesting NEO, 2003 EM1, announced at 3:15pm Eastern Time today in MPEC 2003-E28 with this copyrighted note: "The above nominal orbital elements indicate that the object passed 0.017 AU from the earth and 0.016 AU from the moon on 1974 Mar. 7." (A distance of 0.016 to 0.017 AU is a bit more than six times the distance between Earth and Moon.)
      2003 EM1 was discovered on 5 March, the second amateur-discovered NEO of 2003 by A/CC's tally. This object spins about the Sun almost completely inside Earth's orbit, with perihelion initially calculated at 0.908 AU and aphelion at 1.007 AU. By standard rule-of-thumb estimate from an object's brightness, EM1 is about 35-75 meters/yards wide.
      Crni Vrh has posted the two discovery images as a beautiful 701Kb JPEG showing comet C/2001 RX14 (LINEAR), which was the actual target of the observations (more Crni Vrh RX14 images). The streak that is 2003 EM1 is in the lower right of the two images. Jure Skvarc told the Minor Planet Mailing List today that the image sequence in which he found 2003 EM1 was scheduled in remotely by Herman Mikuz, and, contrary to the MPEC, EM1 was discovered with the observatory's new 0.60m telescope rather than the 0.36m instrument credited.

Reiner Stoss wrote:

We tracked 2003 EM1 from Mallorca last night and it obviously had a high light variation. I sent our observations to Alan W. Harris and he did a quick examination and found a preliminary period of 1.86 minutes.
      This image [above] is the result of stacking five 7-second frames on the asteroid's motion. Due to EM1's fast motion, the stars are not trails, but rather "chains of pearls." The frames were taken between 19:32:09 and 19:33:57 UT on 6 March 2003, and are from a series of 50 frames taken over 20 minutes. These 50 were also used for a very preliminary light curve determination. The telescope used was the 0.30m at the Observatorio Astronomico de Mallorca, observers Salvador Sanchez and Reiner Stoss.

A NASA/KSC news release on 6 March reported that the Space Infrared Telescope Facility (SIRTF) had arrived at the Kennedy Space Center for a launch scheduled for early on April 15th. Other related news releases came 13 March from Cornell and 25 March from JPL. Space.com had an article on 11 March
      One of SIRTF's goals will be to study the Kuiper Belt. See an earlier A/CC report for more about SIRTF, and the April news that the spacecraft was mated with its launcher, only to be removed and the launch delayed again, this time until mid-August 2003.

Although there was no official announcement, New Scientist and BBC reported on 7 March that the decision has been made (or, is "almost certain" to be made) to retarget the ESA Rosetta mission to 67P/Churyumov-Gerasimenko, with a launch in February 2004 and rendezvous around 2014. As A/CC noted on 19 Feb., Daniel Fischer in his Cosmic Mirror issue #249 reported that a Rosetta-related 67P observing campaign had already begun ahead of a decision to retarget.
      ESA put out a 20 March news release reporting that three revised Rosetta comet mission scenarios were still being considered, with starts in 2004 or 2005 to 67P/Churyumov-Gerasimenko, or in 2004 to original target 46P/Wirtanen. Also, SpaceDaily reported 20 March on the present status of Rosetta and other comet missions, including Deep Impact. Another article on SpaceDaily 23 March told about how revised planning is proceeding, including asteroid fly-bys en route.
      An April 10th go-Ariane report said that "Rosetta prime-contractor Astrium Germany, programme managers at ESA and the engineers in Kourou have not found a way to safely defuel the spacecraft without irreversibly damaging it." While fueled, it can't be transported for work or launch elsewhere. And there is a big safety issue in trying to make engineering changes to a spacecraft full of hydrazine, yet modifications are reportedly needed to handle the higher-gravity of likely new destination 67P/Churyumov-Gerasimenko. This independent report is attributed to "reliable sources," including an unnamed Astrium engineer.
      A 17 April article on SpaceDaily contradicted details of the go-Ariane report but confirms there are problems. It said that, while Rosetta's hydrazine tank can be emptied, and will be next month, its companion supply of nitrogen tetroxide oxidizer is "impossible to remove." Thus the Rosetta spacecraft cannot be moved from South America to Baikonur for the heavier-lift Proton launcher needed to still reach original destination 46P/Wirtanen. The sources for this report were Rosetta chief scientist Gerhard Schwehm and (via BBC science editor David Whitehouse) an unnamed Astrium engineer.
      SpaceRef.com posted an ESA memo on 7 May about the successful partial defueling of the Rosetta spacecraft, and states that launch preparations will resume in October with the earliest launch date in late February next year.

The 10 March edition of Cambridge Conference Correspondence carries the text of a Toronto Star article of 9 March about NASA contracting with the University of Western Ontario (UWO) to report on what the odds were that the Shuttle Columbia could have been hit with a meteor large enough to initiate the catastrophy. The answer is "one in 330," based on observation by the UWO Canadian Meteor Orbit Radar (CMOR), which was in operation at the time. There seems to be no Web site with more info about this instrument, but the abstract PDF for a paper presented at last year's Asteroid, Comets, Meteors (ACM) meeting says that it has been operating since January 2002, is fully automated, and "detects most major [meteor] streams and a variety of smaller minor streams." A few meteors have been detected traveling "above the interstellar velocity limit."
      UPI had a story on 12 March citing UWO professor Peter Brown in reporting that, "The danger . . . was no higher than predicted before the flight. . .  The data practically rule out the possibility an unexpected increase in the number of meteoroids might have played a role. . .  NASA estimates there is normally a 1-in-370 chance a collision with a meteoroid or a piece of debris" will affect a mission.
      See SpaceWeather.com's archive for 26 July 2003 for a sky map of meteors picked up by this radar on July 24th (click to see full-size), early in the Delta Aquarid meteor shower, which would peak about four days later.
      See also A/CC links to other Shuttle Columbia meteor-related news.

The University of Massachusetts put out a news release 26 March telling that new products are available from the Two Micron All-Sky Survey (2MASS), an infrared survey that covers nearly 100% of the sky. To better understand what is actually being released and when, and how to get access to it, see the 25 March Data Release announcement from Caltech Infrared Processing and Analysis Center, a 2MASS partner. For older data releases related to minor objects, see also the 2MASS Asteroid and Comet Catalogs page.
      JPL posted a related 27 March news release, CNN on 28 March ran an AP wire story, and Space.com had an 8 April article.

Potentially hazardous asteroids removed from the NEODyS and/or JPL risk pages during March 2003: 2001 AV43, 2003 BK47, 2003 CR20, 2003 DZ15, 2003 EB50 & 2003 FH