The Asteroid/Comet Connection's daily news journal about asteroids, comets & meteors – 2-6 March 2005
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|[ 9 March 2005 news ]|
6 March 2005 - Sunday
MOS on the Web – Minor object science reporting elsewhere:
- "Jupiter's formation linked to that of primitive meteorites," Indiana University 3 March news release: "[Simulations] show that spiral waves in a gravitationally unstable disk of gas and dust at or beyond Jupiter's distance from the sun (five times the Earth-sun distance) could have produced shock waves at half that distance in the inner solar system — especially in the asteroid belt — that were capable of melting dust clumps to form chondrules."
- "Meteor shower seen in South West," BBC 28 Feb. article: "People living in Cornwall have reported sightings of meteors falling from the sky on Sunday night ... believed to be part of the Virginids meteor shower."
- "Another county meteor sighting," Shropshire, England Star 28 Feb. article: "The orange ball with a long, green tail was spotted by residents of Wem and Lyneal at 7.30pm on Saturday."
Crater news & impact theory
- "Controversial ship leaves Mexico," AP wire story 2 March at CNN: ""The research vessel Maurice Ewing sailed from Progresso, Mexico, Tuesday, after completing a research mission [examining the Chicxulub crater] that began on January 12th," according to the press statement [from Columbia University's Lamont-Doherty Earth Observatory (LDEO)]."
- "Mexican crater has new impact," Arizona Republic 1 March article: "Since August, UA geologists David Kring and Lukas Zurcher have published five papers based on drilling done near the site in 2002... Other researchers have been studying honeybees for clues and combing Latin America for debris from the Chicxulub impact." (Also at USA Today.)
- "186-mile-wide crater tops growing list of big holes," Arizona Republic 1 March article
- "Astronomer: Earth safe from asteroids for now," Lexington, Kentucky Herald-Leader 25 Feb.article: "Asked whether Earth would have survived [the pummeling of Shoemaker-Levy 9, Carolyn Shoemaker] says there is disagreement about how large the comet was, but at the very least it would have caused a significant change in climate and the extinction of many species."
- David Morrison's NEO News, "Impacts at the AAAS," 23 Feb. edition at SpaceRef.com 24 Feb.: "There are apparently two global impact layers that have been identified in Italy separated by 10-20 cm, and perhaps these can be linked to the [Chesapeake and Popigai] craters and will provide a measure of the interval of time between the impacts."
Risk monitoring: NEODyS posted 2005 ET2 and 2005 EU2 late today UT. This morning's Daily Orbit Update MPEC reported observation of 2004 MN4 by Pla D'Arguines Observatory in Spain last night, and today NEODyS very slightly changed its risk assessment.
5 March 2005 - Saturday
Rosetta caught at 2010 UT on 4 March by Erich Meyer at Linz Obs. in Austria.
Rosetta flyby: The ESA Rosetta comet mission spacecraft made an Earth flyby gravity-assist maneuver last night (see advance reports below and February 23rd). Erich Meyer sent the image at right, cropped for presentation here, made at Davidschlag Observatory (Linz) in Austria yesterday evening, and Gianluca Masi sent links to an image and animation (1.63Mb GIF) he made with Franco Mallia and Roger Wilcox and the SoTIE remote-controlled telescope at Las Campanas in Chile during 0204-0245 yesterday morning ("North is up, east on the left. Scale is ~2"/pixel").
The Rosetta spacecraft made a brief appearance on the MPC NEO Confirmation page as Catalina Sky Survey discovery 5E2224A, confirmed independently by Robert Hutsebaut and Jim Bedient using Rent-A-Scope at New Mexico Skies. These observations were reported in Distant Artificial Satellites Observation (DASO) Circular 22, and visit the DASO home page for other recent circulars with Rosetta astrometry. (DASO 19 of 22 January includes astrometry from Desert Moon Observatory in New Mexico on January 13th and from George Observatory in Texas on the 14th, both tracking the departing NASA Deep Impact comet mission.)
IEO news: As A/CC noted below, David Tholen casually mentioned a very interesting unknown asteroid while answering questions from the public. He supplied some further information about this inside-Earth orbit object (IEO), 2004 XZ130, in discussion on the Minor Planet Mailing list (MPML), stating that its discovery was on 13 December and that "the orbit has record small semimajor axis and aphelion distance, based on twenty seven observations spanning fifty two days." Not all of those have been submitted to the MPC yet because of camera calibration work, but "perihelion distance is small enough that relativity really needs to be taken into account" for the orbit calculation. He estimates the object's absolute magnitude at H=20.3, and puts its diameter "around 300 m."
In reviewing the remaining known IEO population, there is 2003 CP20 and 2004 JG6, as well as possibly the lost 1998 DK36, which may not be far enough inside Earth's orbit, since it has some low-rated impact solutions. 2002 JX8 was also mentioned by a list member, but Tholen pointed out that it has aphelion (Q) of 1.006 AU, and brought up a debate over how to define "the difference between Aten and Apohele."
If you use what I call a "one-dimensional" definition, then one can either pick a dividing line of 1 AU or dividing lines of 1.017 and 0.983 AU for each case, respectively. Once you start looking at the longitude of perihelion or aphelion to see whether the orbit actually crosses that of Earth, that's what I call a "two-dimensional" definition. By using Q=0.983 AU, you're at least guaranteed that it does not cross.
Risk monitoring: JPL today posted two newly discovered objects as impact risks with highly preliminary risk assessments. 2005 ET2 is a quarter-kilometer-size object with several dozen low-rated impact solutions, and small object 2005 EU2 has more than 44-dozen solutions beginning just over five years from now (it is not unusual to have so many solutions for an object with an observing "arc" that isn't even 24 hours long).
2005 ET2, as announced in MPEC 2005-E26 today, was discovered early yesterday UT by the Mt. Lemmon Survey, part of the Catalina Sky Survey (CSS) in Arizona, and was confirmed last night by KLENOT in the Czech Republic and this morning by Jim Bedient with the Faulkes Telescope North in Hawaii.
MPEC 2005-E25 announced 2005 EU2 today, discovered by CSS itself yesterday morning, and confirmed last night by KLENOT and early today by Sandlot Observatory in Kansas. JPL, which estimates this object to be on the order of 100 meters/yards wide, reports that it will pass Earth at 6.2 lunar distances on April 3rd.
Today's Daily Orbit Update MPEC reported observation of 2005 ES1 from LINEAR in New Mexico yesterday morning, and today JPL removed its two impact solutions for this object, which it estimates at about 10 meters wide.
Update: NEODyS has revised its 2004 VD17 risk assessment, very slightly raising its overall risk ratings but cutting its impact solution count from seven to six. This is based on the same data as the last NEODyS 2004 VD17 assessment of January 28th, but with one astrometric position, not just rejected, but eliminated. (JPL's assessment uses even fewer data points from within the observation arc — 698 of 718 positions.)
4 March 2005 - Friday
FMOP news: Spacewatch discovery SW40L3, which was "Added Mar. 3.34 UT" to the Minor Planet Center NEO Confirmation Page (NEOCP) and is still there today, was found on the morning of March 3rd by Robert Klein in Maryland working as an online volunteer with the FMO Project reviewing images from the Spacewatch 0.9m telescope in Arizona. He also discovered 2004 TJ10 last October. Update: SW40L3 was not confirmed.
Risk monitoring: JPL today posted 2005 ES1 with two very low-rated impact solutions for February 2069. This object was announced today in MPEC 2005-E20 as discovered by the Catalina Sky Survey (CSS) in Arizona and confirmed by the nearby sibling Mt. Lemmon Survey yesterday morning. JPL puts 2005 ES1's diameter on the order of 10 meters/yards and reports that it flew past Earth at five lunar distances on February 24th, eight days ago during the bright Moon.
JPL posted 2005 CZ36 as a risk yesterday, but removed it early on the 4th UTC, still the 3rd in Pasadena. This kilometer-size PHA doesn't have a discovery MPEC, but additional observations were reported yesterday in MPEC 2005-E13. The discovery was made on February 6th from Uccle Observatory in Belgium, which followed it on the 7th but didn't pick it up again until late on the 27th. Great Shefford Observatory in England observed it on the night of March 2nd and Sabino Canyon Observatory in Arizona the next morning. Yesterday's Daily Orbit Update (DOU) also reported observation that morning by Jim Bedient with the Faulkes Telescope North in Hawaii.
Yesterday's DOU was time-stamped at 0705 UTC, but it wasn't posted to the Web until many hours later, and may also have been delayed in E-mail delivery. JPL lowered its 2005 CC37 risk assessment yesterday, but NEODyS didn't update its risk assessments with that data until today, lowering its overall risk ratings for 2005 CC37 and very slightly changing its 2004 MN4 ratings. The observations of 2005 CC37 came from UKAPP in Northern Ireland with the Faulkes North on March 2nd, and of 2004 MN4 from Petit Jean Mountain South Observatory in Arkansas on the morning of the 2nd and that night from Herrenberg Observatory in Germany.
Today's DOU reported no observations of objects with impact solutions.
2 March 2005 - Wednesday
MOS on the Web – Minor object science reporting elsewhere:
- "Amateur watchers invited to 'Rosetta Up Close' photo contest," ESA 28 Feb. news release: "After sunset in Europe on Friday, 4 March, the spacecraft will appear to travel from south east to south west ... at an approximative angle of 30 degrees over the horizon ... disappearing below the horizon shortly after 23:00 CET. As seen from Europe, it will only reach a magnitude of about +8 or +9 ... dimmer than a typical faint star and not readily apparent to the eye."
- Pasquale Tricarico has posted some Rosetta animations at ORSA@work along with information about visualizing the flyby.
- "Earth Fly-by Approaches," ESA Rosetta mission status report 28 Feb. for the period 14-24 Feb.: "The main activity of the reporting period was the last trajectory correction manoeuvre before Earth swing-by ... executed successfully on 17 February." — Note: There is no report posted for the period 28 Jan. to 13 Feb.
- "March Geology and GSA Today media highlights," GSA 28 Feb. news release at EurekAlert — Note: Includes a revised age estimate ("144.6 +/- 0.8 million years before present") for the Jurassic-Cretaceous boundary, which may, or may not, involve a major impact event, and an article on "Discovery of distal ejecta from the 1850 Ma Sudbury impact event," which is "the second largest and third or fourth oldest extraterrestrial Earth impact site." It says "The debris (ejecta) studied here, landed 650 km west northwest of Sudbury near Thunder Bay, Ontario, Canada, and 875 km west of Sudbury near Hibbing, Minnesota, United States."
- Calendar item: The Sedimentary Record of Meteorite Impacts, 21-22 May 2005, Southwest Missouri State University at Springfield, to "provide opportunities for communication on ... topics across a wide range of scientific specialties such as impact stratigraphy, sedimentology, petrology, mineralogy, geochemistry, paleontology, paleomagnetism, hydrogeology, economic geology, and numerical modeling," and will include "a workshop featuring core from the Decaturville and Weaubleau-Osceola structures. The conference will conclude with a field trip to the Weaubleau-Osceola structure on Sunday May 22 [and an] optional field trip to Decaturville and Crooked Creek structures the following day." See also the second announcement and a report (1.91Mb PDF) on the conference subject. (There's some other very interesting reading on the hosting site, including a photo essay on Ries Crater and Steinheim Basin in Germany.)
- "Time for an atomic change," ABC Australia 22 Feb. article: "Australia will officially move to a new national time standard based on the atomic clock from September. The system, know as co-ordinated universal time (UTC), will replace traditional Greenwich Mean Time (GMT)."
- "The PI's Perspective," New Horizon mission 7 Feb. commentary: "Other important project milestones achieved of late include Los Alamos National Laboratories' completion of fuel processing for the radioisotope thermoelectric generator (RTG) that would be used on the mission."
Bits & pieces: David Tholen answered Universe Today reader questions about asteroids on February 24th. There he mentions inside-Earth orbit (IEO) 2004 XZ130, saying that it has "a record small semimajor axis of 0.617 AU and a record small aphelion distance of 0.898 AU." This is news to A/CC, and neither NEODyS nor JPL have it in their public databases, and it doesn't appear in any other of the usual places to find NEOs listed, but you can bring it up on the MPC Ephemeris Service with positions calculated from Vaisala elements.
Monty Robson at John J. McCarthy Observatory in Connecticut notes Peter Birtwhistle's Web page at Great Shefford Observatory in England telling about their collaboration to experiment with "Direct Distance Measurement of NEOs by Parallax."
And Rob Matson reports about yesterday's Daily Orbit Update MPEC that it was he who precovered NEO 2004 RM251, reporting two positions from 29 September 1987 from Mt. Palomar in the Digitized Sky Survey 2 (DSS2) archive. "The old arc was from 9/14/2004 - 2/27/2005 (5-1/2 months); now that the arc is over 17 years, the uncertainty parameter dropped to U=0." This object was discovered by LINEAR (MPEC 2004-R88).
Risk monitoring: No objects with impact solutions had observations reported in today's Daily Orbit Update (DOU) MPEC. Yesterday's DOU reported observation of 2004 MN4 from Jakokoski Observatory in Finland late on February 28th, and of 2005 CC37 from that morning by Great Shefford Observatory in England. Yesterday NEODyS very slightly raised its overall risk ratings for 2004 MN4 and raised its still-low risk assessment for 2005 CC37, while JPL slightly changed its low 2005 CC37 risk assessment.
|[ previous news: 28 February 2005 ]|