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Last Month in Astronomy


06-JUN-2011 • Marcy Strikes Back • Geoff Marcy is angry and he probably has every right to be. He is upset at the cancellation of the Terrerstrial Planet Finder (TPF). Marcy says “I think TPF is our human genome project ... Free-flying interferometers in space are the only plausible future for astrophysics.” Instead, there was a lot of squabbling between the interferometer types and the coronagraph types. “Now we have nothing”. A version called TPF-Lite did not make the cut for the 2010 Decadal Survey and with it went the $600 million that NASA had already spent.

01-JUN-2011 • Endeavour Lands • Endeavour has completed its last mission. It is slated to find a home at the Los Angeles Science Center near USC. The mission installed the AMS-02 Alpha Magnetic Spectrometer which might end up being the most important scientific apparatus on the ISS. It may help in the hunt for dark matter. The last shuttle launch will be STS-135 onboard Atlantis and its launch date is NET July 8.

27-MAY-2011 • Green Rain • The Spitzer telescope has made some observations of a star that is being rained on. The “rain” is actually crystals of olivine, a green mineral that seems to get a lot of press for showing up off of Earth. Tom Megeath the PI for this research thinks he knows what is happening. “We propose that the crystals were cooked up near the surface of the forming star, then carried up into the surrounding cloud where temperatures are much colder, and ultimately fell down again like glitter.” The star, actually a protostar, is HOPS-68 in the constellation Orion. The olivine crystals are in the form of fosterite which can be found on Hawaiian beaches, a result of cooling lava. But it was also found in the Stardust and Deep Impact missions.

26-MAY-2011 • Mars Early Start • A computer simulation suggests that Mars formed relatively quickly, in just 2 to 4 million years. Earth, on the other hand, took 50-100 million years; starting Mars-sized but then growing via collisions with solar system debris. Some of the input for this simulation came from measurements of the radioactive decay of hafnium to tungsten. This measurement was done on meteorites that originally came from Mars.

25-MAY-2011 • OSIRIS-REx • The University of Arizona has been selected by NASA to lead an asteroid sample return mission. This is called OSIRIS-REx which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. The target asteroid is 1999 RQ36 indicating the year that it was discovered was 1999. This asteroid is 575 meters in diameter. The $800 million dollar mission (not counting the launch vehicle) should launch in 2016. Another year to remember is 2182. That’s the year 1999 RQ36 may hit Earth; current odds are 1 in 1800. The mission will act like the paparazzi with a touch of kleptomania. For a year the spacecraft will study the asteroid from close range. Then it will take samples from the asteroid and return them to Earth in 2023. This is the kind of asteroid that is expected to contain organic molecules.

25-MAY-2011 • Spirit’s Mission Ends • The Mars Rover Spirit has come to the end of its mission. It has not responded to commands since March 22, 2010. According to program manager John Callas “Spirit, with her degraded 5-wheel driving, broke through an unseen hazard and became embedded in unconsolidated fine material that trapped the rover. ... We conducted a very ambitious extrication effort, but the extrication on Mars ran out of time with the fourth winter and was further complicated by another wheel failure.... Spirit likely ran out of energy and succumbed to the cold temperatures during the fourth winter. ... a lack of response from the rover after more than 1,200 recovery commands were sent to rouse her indicates that Spirit will sleep forever.” The 3 month original duration turned about to be 6 years and some. Imagine if your laptop that came with a 2 year warranty lasted for 48 years. The Rover Opportunity continues to function.

18-MAY-2011 • Remember to duck! • Astronomers have discovered a class of Jupiter-sized planets that are floating through the galaxy unattached to any stars. It was always believed that orbital dynamics could result in some planets being ejected from their stellar systems. The finding of hot Jupiters around some stars which may have formed at some distance from their star and then moved in, increased the likelihood that some planetary ejections occur. But a survey of the center of Milky Way galaxy originally done in 2006-2007, shows evidence of 10 such orphan planets. Unless the survey was looking at a particular good spot for such objects, the implications are that there must be twice as many free-range Jupiters as there are stars in our galaxy. Yes, that means possibly 400 billion such things. Then consider that Earth-sized orphans are even more likely to occur.


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