Draconid Meteor Outburst: Observations by BAA members and non-members indicate that a short-lived outburst of Draconid meteors occurred on 2011 October 8. Draconid rates were generally low until around 1900 UT on October 8 when a rapid increase in activity occurred, peaking between 2005 and 2015 UT.
Thereafter there was a rapid decline, with Draconid meteor rates returning to a low level by 2130 UT. A very preliminary analysis of visual observations made by a group of observers led by the Director (Dr John Mason), observing from near Goreme in central Turkey, indicates that the peak equivalent ZHR was about 350 m/h between 2005 and 2015 UT, although correction factors are high due to the effect of bright moonlight. It is possible that lesser,
short-lived secondary bursts in Draconid activity were also noted around 1915 and 1938 UT.
Observers in the UK & Ireland had to contend with cloud and rain on the evening of October 8, but it is extremely encouraging that so many individuals and local society groups battled the elements in the hope of getting a view of the shower.
More observations of the Draconid outburst, using photographic, visual, and radio techniques, from individuals and groups in the UK and overseas, are urgently required to build up a full picture of the shower's rapidly changing activity. Even if you have only glimpsed a
few meteors during a short-lived break in the clouds, the BAA Meteor Section would like to receive your report.
So if you did manage any sort of observations, please submit them to the BAA Meteor Section via email to: meteor@britastro.org.
Alternatively, submit them to the International Meteor Organisation: www.imo.net.
3. ROSAT TO CRASH BACK TO EARTH: Readers in the S half of Ireland have another (VERY slight!) chance to get hit by a satellite crashing back to Earth later this month. Since it never passes further North than 53 degrees, only those living South of the latitude of Birr (approximately) could be in the fall zone.
The ROSAT X-ray astronomy observatory is smaller and less massive than NASA's Upper Atmospheric Research Satellite, or UARS, which fell back to Earth on Sept. 24. But officials predict it will spread three times more debris and pose a greater threat to people than UARS. That's because ROSAT is made of heat-resistant components, especially its primary mirror, which officials say will probably be the largest single fragment that will reach Earth. The satellite will streak into the atmosphere at 17,000 mph, and temperatures up to 3,000 degrees Fahrenheit will burn up much of the spacecraft.
"All these forces exerted on the satellite cause it to disintegrate, which in turn means that it eventually lands in the form of a long debris trail," said Heiner Klinkrad, head of the European Space Agency's space debris office. "The lightweight objects fall to Earth first, similar to leaves from a tree. The really heavy objects land later, because they ultimately have to drill their way through the atmosphere."
But engineers expect the bulk of ROSAT to survive re-entry, littering its impact point with up to 30 pieces of debris. ROSAT does not have an engine or propulsion system because it used reaction wheels to point its telescope toward scientific targets in the cosmos. Up to 3,750 pounds of the satellite could reach Earth's surface. By contrast, NASA said they expected 1,200 pounds of UARS to survive re-entry.
There is a 1-in-2,000 chance someone will be struck by fragments of ROSAT on its way down, according to Germany. That's odds of about 1-in-14 trillion that any individual person will be hit. The threat from UARS wasn't as high. An analysis from NASA showed there was a 1-in-3,200 chance of a collision between a human and a piece of UARS. The remnants of UARS fell in the remote Pacific Ocean, and ROSAT will likely also end up in the sea.
ROSAT, which stands for Roentgen Satellite, was turned off in 1999, and its altitude has gradually dropped since then from an operational orbit more than 350 miles high. The German Aerospace Center, also known as DLR by its German acronym, says the spacecraft should re-enter the atmosphere between Oct. 20 and Oct. 25. But the margin of error in the re-entry forecast is three days, and officials likely won't know where the satellite will come down until after it falls. Even one day before re-entry, the time of ROSAT's demise will only be known with a precision of plus-or-minus five hours, putting entire oceans and continents in the satellite's flight path.
"All areas under the orbit of ROSAT, which extends to 53 degrees N and S, could be affected by its re-entry," said a posting on DLR's website. "The bulk of the debris will impact near the ground track of the satellite." "It will not be possible to make any kind of reliable forecast about where the satellite will actually come down until about one or two hours before the fact," Klinkrad said. "It will, however, be possible to predict, about one day in advance, which geographical regions will definitely not be affected."
"This slow descent is due to the friction encountered by the satellite as it enters the outer fringes of Earth atmosphere, which increases the more ROSAT penetrates into our atmosphere. The major factor affecting a satellite's fall from orbit is solar activity. Energy unleashed from the Sun causes Earth's atmosphere to heat up and expand, generating more drag for satellites in low orbits", Klinkrad said.
Fluctuations in solar activity can quicken or slow a satellite's re-entry. Experts initially expected ROSAT's plunge to occur last year, but solar activity turned out to be less than predicted, delaying the re-entry until this month.
5. Asteroid to pass 'through' M31. (This has been adapted from a BAA email. T.M.) The bright (magnitude 11) asteroid (372) Palma will pass less than 15' north of the nucleus of the Andromeda Galaxy (Messier 31) on the evening of October 21/22. It will take the asteroid about 5 days to cross the galaxy between roughly the dates of October 18-23. The large majority of asteroids do not stray too far from the Ecliptic and so cannot reach M31. Although Palma occupies the asteroid Main Belt, it has an unusually high orbital inclination, and on this occasion it will be about 34 degrees north of the Ecliptic such that it crosses in front of the Andromeda Galaxy.
The best photo opportunity will probably occur on the evening of Oct 22/23 when Palma will lie between the core of M 31 and M 110 (NGC 205). The following evening (Oct 23/24) it will pass some 13' south of Messier 110.
A finder chart (courtesy of Graham Relf of the BAA Computing Section) showing the general path of Palma is available at: http://britastro.org/computing/ch/372Palma2011Oct21(J2000).png. N.B. It will be necessary to take a time-series of images and stack these
to show the trail of the moving asteroid as its apparent speed is only 34" per hour.
6. MARS SCIENCE LABORATORY TALKS: Kevin Nolan, very well-known in Irish astronomy circles, will be giving a new talk titled "Mars Science Laboratory: In search of Origins" to celebrate the Science Week Theme of "The chemistry of life" and the launch of MSL-Curiosity the week after (On November 25th). Kevin is the Irish Representative of The Planetary Society, and is the author of an excellent book on Mars; "Mars, A Cosmic Stepping Stone", published by Springer. (See the great reviews at http://www.amazon.co.uk/Mars-Cosmic-Stepping-Stone-ebook/dp/B001VNCFBC)
He will be giving the same talk three times - in Dublin (Mansion House on Monday 14th), Galway (NUI Galway on Nov 16th) and Blackrock Castle Observatory (Friday November 18th).
Kevin adds: "On a related note, I have just launched the new Planetary Society Ireland web site at www.planetary.ie.
It's quite basic now but is being used to promote the talk at www.planetary.ie/msl. I've also created a new twitter account @planetarie and will be tweeting in selected areas of TPS News, Space News and Policy issues, Mars Exploration and Irish Astronomy matters. While I have few followers just now, Forfas-DSE, BCO and nightsky.ie are retweeting my tweets and these, along with other mechanisms such as the talks in November and an intended blog (planetarie.wordpress.com for 2012) I hope to build a following. I will always be delighted to tweet any IAA news that you need further circulation on (as and when I develop a following!!)."
7. Paris house hit by meteorite: (Thanks to Barry Pickup for the alert to this item.) A meteorite crashed through the roof of a Paris house some time in September. Scientists said it was the closest such a space rock ever found to Paris and one of only about 60 meteorites to have landed in France in the past 400 years. In a further twist of fate, the family who received the object in Draveil, about 12 miles south of Paris, are called the Comettes.
It is thought the meteorite struck the house a few weeks ago when the Comettes were on holiday, which explains why they did not hear it crash landing. They only found out when the roof started leaking. "We got the roof tiler round and he was astounded," said Martine Comette, 32. "He said: 'You need to be Superman to break a tile like that! It must be a meteorite.'" The rock had gone through the roof and was wedged in glass wool insulation.
Alain Carion, a mineral scientist and meteor hunter, said the iron-rich celestial rock known as a "chondrite" was easily identifiable thanks to a "black fusion crust that characterises the crossing of the Earth's atmosphere". With an age of around 4.57 billion years, the 3oz egg-sized object came from an asteroid belt between Mars and Jupiter, he said.
Mrs Commette was still getting to grips with the improbability of such an event. "A météorite landing in your garden is magical and more unlikely than winning the Lottery," she told Le Parisien. While rocks from Mars are estimated at almost £1,000 a gram, the Draveil meteor would only fetch a few hundred euros, according to Mr Carion. In any case, the family has no wish to part with it. "It's the history of life on Earth has landed in my garden, the history of space of which we known nothing and which is fascinating," said Mrs Comette. See: http://www.telegraph.co.uk/science/space/8818456/4.5-billion-year-old-meteorite-crashes-into-Paris-family-home.html
8. Moseley imaged by WISE spacecraft! OK, please forgive the journalistic license - actually, it imaged 'my' asteroid / minor planet, "16693 Moseley". I got this alert from Prof Alan Fitzsimmons at QUB: "Hi Terry, Don't know if you already know this, but your asteroid was seen by the WISE mission. You have a diameter of 5.5+/-0.7 km and an optical albedo of 0.25+/-0.06. See: http://arxiv.org/abs/1109.4096. All the best! Alan" (Small, maybe, but beautifully formed, I'm sure!)
Terry Moseley
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