SJAA Ephemeris December 2012 | SJAA Home | Contents | Previous | Next

The Last Month in Astronomy


NOV-3-2012 • A FOXSI launch • A sounding rocket carrying a next-generation X-Ray telescope was successfully launched from White Sands New Mexico. The suborbital flight was a success although almost all of the backup instruments had to be used and they only get about 6 minutes to take images. The detector is said to be 50 times more sensitive than previous spacecraft.

NOV-2-2012 • Comet Breaking Up • According to Rachel Stevenson, a post-doc at JPL, Comet 168P/Hergenrother is breaking apart and “we have resolved that the nucleus of the comet has separated into at least four distinct pieces resulting in a large increase in dust material in its coma.” That added material in the coma means the comet is brighter.

OCT-25-2012 • The Return of Fomalhaut b • It was 4 years ago that Hubble captured an image of an exoplanet around the star Fomalhaut. This was the first time that a direct image of an exoplanet was performed. Later studies suggested that it was not an exoplanet at all and so the existence of Fomalhaut b was considered dubious. Now its existence has been reaffirmed. The new study used some old Hubble images (2004 and 2006) and a new image taken in the ultraviolet. This showed that the planet was relatively consistent in its orbit.

OCT-24-2012 • Lonely Stars • There is a mysterious glow of infrared light seen across the sky. It is not the background from the Big Bang, that’s far lower down the electromagnetic spectrum. One theory is that the infrared glow comes the first stars and galaxies. The stars are far too dim to be observed but their collective light is still seen. Now a new study gives an alternative view. The glow might come from a large number of stars that have become unmoored from their galaxies as a result of galactic mergers or at least near encounters where tidal surfaces stripped stars into intergalactic space. This theory better fits the data from Spitzer observations because the glow is too bright to be from early galaxies which are thought to be smaller than modern galaxies.

OCT-22-2012 • Elliptical Spiral? • As we were taught on our mother’s knee, galaxies are either elliptical, spiral or irregular if we really can’t tell which. But there is no such thing as an elliptical with spiral arms, right? Ahem, Centaurus A is an elliptical galaxy with a spiral galaxy embedded inside. It can be seen by studying data from the submillimeter wavelengths. In fact, we may find similar galaxies like this using the new Atacama Large Millimeter/submillimeter Array (ALMA). In the case of Centaurus A, the spiral galaxy was swallowed up about 300 million years ago and the spiral arms may last that long again.

OCT-19-2012 • Evolution Evolves • A study of galaxy images using the Keck telescopes and the Hubble Space Telescope has changed the way astronomers think about galactic evolution. The prevailing notion is that galaxies were different in the early universe but the current galactic scene has been fairly steady for 8 billion years. But Susan Kassin from NASA Goddard says “The trend we’ve observed instead shows the opposite, that galaxies were steadily changing over this time period.”

OCT-17-2012 • Jupiter Study • NASA has put together a set of Earth-based Jovian images that show how weather is changing on that planet. Note (see thumbnail on the left, click it to see a larger image) how the Southern Equatorial Band disappears in 2010 and returns in 2011. The visible-light images in the left column were taken by amateur astronomers. The middle and right columns are infrared images taken by NASA’s Infrared Telescope Facility or the Subaru Telescope both in Hawaii. The Northern Equatorial Band (NEB) thinned out but it is making a comeback. Image credit: NASA/IRTF/JPL-Caltech/NAOJ/A. Wesley/A. Kazemoto/C. Go

OCT-17-2012 • Alpha Centauri B b • For years it has been an open question. Surely we must have looked at our closest star system looking for exoplanets but we haven’t found any. Well, first, don’t call me Shirley. Second, it turns out it does have a planet after all. The planet found is Earth sized but very close to its K-type star. It has an orbital period of just over 3 days and is probably not habitable. But since it is Earth-sized rather than Neptunian or larger, it may have rocky planets further away from the star.

OCT-15-2012 • A 4 Star Planet • An exoplanet has been found in a stellar system with 4 stars. The planet orbits a pair of stars so that makes it a circumbinary, i.e. it goes around (“circum”) two (“binary”) stars. But this system has two other stars that orbit the two inner stars at some distance. This makes it the 7th circumbinary planet but the first in quadruple system. The planet, designated PH1, is around the size of Neptune. The two distance stars are 1000 AU from the central stars. The designation PH1 is in honor of the Planet Hunters website. The planet was discovered largely through the efforts of citizen scientists (“amateur astronomers in my book”) who joined others at the website to characterize light charts that expose transiting planets.


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