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By Daniel Fischer Every page present in Europe & the U.S.!
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The latest issue!
| A German companion! (SuW version) Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
Two more moons bring Saturn's total to 24 - S/2000 S 5 & S/2000 S 6: IAUC. Sulamitis occultation not observed? Dunham Message. Previews: IOTA, JPL Releases.
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Leonids 2000 peak at over 400/hour!For the 2nd year in a row the Leonid meteors have displayed the highest rates at the times predicted by the only scientific model - and again the maximum was some 5 times higher than predicted. The celestial mechanics of the dust trails left by comet Tempel-Tuttle are thus well understood, but the distribution of the dust and its density are not. Since the latter has been underestimated again (though the predictions for 2000 had extreme error bars in the first place), might one conclude that the probability for big Leonid meteor storms in 2001 and 2002 is now greater than ever ...?The handfull of competing predictions for the 2000 Leonids were already dealt a (probably fatal) blow on November 17 when none of the major outbursts they had anticipated took place: There were neither 900 meteors/hour at 8:00 nor 3500 to 50,000 at 9:20 UTC - instead the Zenithal Hourly Rate reached around 100 at 6:00 UTC and again at 8:00 UTC. The first peak (seen mainly from the Canary Islands) is somewhat controversial, but the 2nd one was well observed in the Americas - and it came precisely when an outburst from the 1932 dust trail was thought possible. The Earth didn't come very close to it and yet there apparently was an encounter with its dust particles. On the morning of November 18 the ZHR was already back at 100 when the UTC day began, slowly rising to 200 at 1:30 UTC. A first peak of almost 300 occured at about 3:45 UTC, just as predicted for the 1733 dust trail, and those lucky few in Europe with no clouds had a nice view (the Moon was not as much a nuisance as had been feared). The ZHR then fell back slightly to 220, only to peak again at over 400 at about 7:15 UTC: That peak came about 1/2 hour earlier than predicted for the 1866 dust trail, the only noticeable deviation from the model. Two hours later the ZHR was back below 100 and the 'trial run' for 2001 was over. May the data collected by the Leonids Rapid Communication Network of the International Meteor Organization and by other bodies help us make even more reliable predictions for then! |
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Very low mass object found just 13 light years awayIt ranks between the 12th and 40th nearest neighbor known to exist in the vicinity of the Sun: DENIS-P J104814.7-395606.1, an object of only 60 to 90 Jupiter masses that has only now been discovered in the DEep Near-Infrared Survey (DENIS) and studied in detail. This dwarf star or Brown Dwarf (it's close to the limit at 75 Jupiter masses) had first caught the DENIS scientists' attention because it is both very red and usually bright. But only a Keck spectrogram could demonstrate that it was a nearby dwarf and not a distant bright giant: It showed the presence of a strong cesium absorption line as well as titanium and vanadium oxyde bands while lithium was missing (thus the lower mass limit of 60 Jupiters).The distance was later estimated with the help of the high proper motion of the object that had by then be recoverd in old sky photos. But How could a star so close to us remain undiscovered until today? Despite of its proximity it is faint because of its low-mass and cool temperature. These faint stars and brown dwarfs have so far escaped from the attention of astronomers, particularly in the southern hemisphere, which has been observed less systematically than the northern hemisphere. DENIS allows to identify them easily and will soon provide a census of very low-mass stars and brown dwarfs in the solar neighborhood. DENIS-P J104814.7-395606.1 becomes the brightest example of its spectral class, and it is therefore a benchmark for future studies of very low-mass stars and brown dwarfs. |
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UK announces intention to join ESONow it's official: The Particle Physics and Astronomy Research Council (PPARC), the UK's strategic science investment agency, on Nov. 22 announced that the government of the United Kingdom is making funds available that provide a baseline for this country to join the European Southern Observatory (ESO). This is good news for the organization which will keep or expand its lead over the U.S. in key areas of groundbased optical astronomy, but the the UK tough choices loom: In order to pay the big entrance and membership fees of ESO, some national astronomy programs are in danger of cancellation. But joining ESO had been considered a top priority for UK astronomy following a community report to the UK Long Term Science Review, which set out a programme of opportunities and priorities for PPARC science over the next 10 to 20 years. |
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Four Earth satellites launched - three live, one lostA Russian Kosmos-3 and an American Delta 2 have launched four small Earth observation and space physics satellites on Nov. 21, but the Russian passenger hasn't been heard from since. The American, Argentinian and Swedish payloads of the other launch are working fine, however.
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Mir to be ditched next February - and this time the Russians mean itTime for space station Mir has run out: After weeks of confusing statements (see Updates #206-208) the Russian space agency on Nov. 16 made the official announcement that the station will be sent into the Pacific 1500 to 2000 km off Australia in late February 2001, just after the 15th anniversary in orbit of the core module. The efforts of MirCorp to save Mir seem to be all but over, although the company is still waiting for official word from the Russian government: "MirCorp is aware of a Russian Space Agency statement on the possible deorbiting of the Mir Space Station in February," a terse statement reads: "MirCorp is awaiting official notification on the future of Mir, and will provide more details when available." A week later, still no other statement has been released, though MirCorp's homepage is now urging you to read this October Feature Story.Russia meanwhile is continuing to train two cosmonaut teams to prepare Mir for its fiery demise in case automated controls to fly the station into the atmosphere fail. Energia, which operates the station for the Russian space agency, expects that both the prime and the backup crew will remain on Earth, but there are two likely scenarios that would mandate an an emergency mission to Mir: a flight control system failure (more likely) or a failure of the docking of Progress M1 with the critical fuel load for the deorbit maneuver. The Progress is already bring equipped for its "historic voyage." Dennis Tito, the first prospective paying Mir visitor, has meanwhile switched his dreams to a short flight to the ISS in April 2001 where he would try not to interfere with the construction work ... |
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The end of the EUVE missionThe mission of the Extreme Ultraviolet Explorer (EUVE) satellite has run its course, NASA has declared, and the final shutdown sequence will be conducted in December: NASA Press Release, Spacefl. Now, SpaceRef, Homepage.Spectrum-Roentgen-Gamma really to fly? Completion & launch of this long-delayed Russian-West European high-energy X-ray satellite is called one of Russia's top priorities in unmanned space exploration: Interfax. Science teams chosen for SIRTF, the Space Infrared Telescope Facility now set for launch in July 2002: JPL Press Release. And in 2004 Japan plans to launch ASTRO-F, also known as the Imaging Infra Red Surveyor (IRIS): paper by Pearson & al. Launch of Genesis mission delayedLaunch of a spacecraft designed to snag samples of solar wind will be postponed for several months - NASA has approved the slip for the Genesis spacecraft, to give breathing room to teams working to ready both Genesis and the 2001 Mars Odyssey mission: SpaceViews.Pluto mission remains cancelled despite growing protests: Wash. Post and Space Daily plus an earlier story on NASA's Outer Planets problems. Back to the drawing board for SIM - NASA has ordered the JPL to try to shrink the cost of the ambitious Space Interferometry Mission from an estimated $1.5 billion: SpaceViews. Stardust survives solar stormThe comet probe went into a safe mode when hit by a "monster cloud of energized particles" from the Sun on Nov. 9 but has been recovered since: JPL Press Release, more details, Science@NASA, RP, SpaceRef, AP.How to fly your spacecraft through comet dust - several missions face that problem in the next couple of years: Space.com. Studying the Chicxulub crater dynamics and why the crater has such a strange ring: Imperial College News Release (other version), Space.com story. The discovery of Argon in Hale-Boppin 1997 shows that the comet is enriched in Ar relative to cosmogonic expectations - and this in turn indicates that Hale-Bopp's deep interior has never been exposed to the 35-40 K temperatures necessary to deplete the comet's primordial argon supply: paper by Stern & al.Astronomers conducting post-mortem on Comet LINEAR - the comet might have been starting to come apart as early as the second week of June, when significant variations in the comet's brightness were first detected: JHU News Release (SpaceRef, EurekAlert versions). |
Iridium satellites saved?A new company, Iridium Satellite LLC, says it will purchase all of the existing assets of Iridium LLC, including the satellite constellation, the terrestrial network, Iridium real property and intellectual property owned by Iridium LLC, while Boeing will operate and maintain the satellites: a Press Release. But why was this release withdrawn again within hours? SpaceViews item 3.Cassini movies show Jupiter's dynamic cloudsin action - one clip, from images taken over a five-day period in October, catches winds swirling counterclockwise around the Great Red Spot: JPL Release, APOD, the GRF movie and a still, the other movie and a still, and coverage by Space.com, CNN, Spacefl. Now. Huygens shields Cassini: ESA Science News. More fine amateur photos of Jupiter: the last 3 letters in CMO. Jupiter, Saturn now prominently visible in the sky: Space.com.Europe's role in Mars research was discussed at an International Mars Exploration Working Group meeting - there will be new contributions starting in 2007: ESA Science News, SPIEGEL, Spacefl. Now, BdW. More evidence for water on Mars? MSSS Release (Spacefl. Now version), Discovery, BBC. Solar System Lithograph: Spacelink. Portugal becomes ESA's 15th member statePortugal has expressed particular interest in contributing to ESA's activities in space science, and technology and applications: Press Release.The booms of all Cluster satellites are deployed and the path is clear for commissioning: ESA Science News. The satellites have observed the Nov. 9 solar storm (that also affected Stardust and alerted the ISS crew): ibid. Ariane 5 does it again, this time with 4 satellitesand a record total payload of over 6 metric tons: DERA Press Release and details, RAS and Panamsat Press Releases, coverage by CNN, AFP, AP, SpaceViews.China offers rare look at its emerging space program, releasing a policy paper that calls for boosting commercial launch services with more powerful rockets and putting a man in orbit by the decade's end: the paper, coverage by Spacefl. Now, SpaceRef, AP, SpaceViews. More recent statements: Space Daily. A msec pulsar in SN 1987Ahas perhaps been detected in optical observations - if true then it's spinning down quickly, and gravitational waves could be detectable by LIGO and TAMA: papers by Middleditch & al. und and Nagataki & Sato.Are pulsars strange stars? Stringent limits on pulsar radii seem to indicate that pulsars are strange stars rather than neutron stars: paper by Kapoor & Shukre. |
All other historical issues can be found in the Archive.
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Compiled and written by Daniel Fischer
(send me a mail to dfischer@astro.uni-bonn.de!), Skyweek