Hello, astro-nuts!

Another chilly morning here in central PA! Did anyone catch any Taurid fireballs this morning? As I mentioned Tuesday, the shower is active and at its maximum through the 12th. You may not see very many but what you could see may be a few bright fireballs. Meanwhile, a new astronomy video has been mosted, and more data from the most recent MESSENGER flyby of Mercury has revealed some interesting information, while Spitzer and Chandra have both been kept busy with new observations.

Check This Out!

The Cassini spacecraft on Monday made a pass through one of those infamous Enceladus plumes. The craft had made close approaches before, but this was the first time it had taken such a close look at one. These plumes are thought to contribute some of the particles in Saturn's ring system, and are thought to originate from a liquid ocean under the surface of Enceladus. Cassini came within about sixty miles of the moon's surface on Monday as it flew through the plume. Since 2005, astronomers have been trying to find out as much as possible about these plumes; thus far we know they contain water vapor, sodium and organic molecules. More information was needed to find out the source of the plumes and potentially whether Enceladus can support lifeforms.

Speaking of "firsts", the "first light" celebration for the 32-inch reflecting telescope at the University of Utah's Willard L. Eccles Observatory is being planned for November 11th. A symposium and reception will be held on campus at the James Fletcher Building beginning at 4pm. The telescope captured its first image on October 15th; spiral galaxy NGC 891in the constellation Andromeda. Because of the 250 mile distance between the campus and the telescope, the hope is that a grant request for remotely controlling the telescope will be approved.

Hubble's new Wide Field Camera 4 has captured some beautiful images of spiral galaxy M83. Check out the story at the Hubble website.

Astronews!

The MESSENGER spacecraft recently made its third flyby of Mercury (September 29), during which it completed a gravity assist in order to remain on course for entering orbit around Mercury in 2011. Not only that, but more images were captured that allowed astronomers to see another six percent of the planet's surface. All told, around 98 percent of Mercury's surface is now imaged, just from efforts by MESSENGER! The only places that haven't been imaged are the polar regions, and that will be handled once MESSENGER goes into orbit. During each flyby, some new surprises were discovered; the third flyby revealed an odd depression that was thought to be volcanic, a double-ring impact basin about 180 miles across. The "inner floor" of the basin appears to be the youngest feature, differing in color from the rest of the area. It is thought that this material could be the youngest volcanic material on the planet. MESSENGER's instruments conducted studies on the exophere of the planet, while some scans of the poles were conducted. Additional information gathered from the flyby was that iron and titanium are abundant at Mercury's surface, contrary to earlier observations that iron levels were low. MESSENGER will have made 15 trips around the sun by the time it enters Mercury's orbit; to date is has traveled about 75% of its 4.9-billion mile trip.

Prior to beginning its "warm" mission, the Spitzer Space Telescope had been keeping an eye on a planetary system that still has a bit of organizing to do. Similar to times long ago when our solar system was young, the planets had not yet made their way into their current stable orbits, and were quite wobbly. The central star, HR 8799, is about 125 light-years from Earth in the constellation Pegasus, and has what appears to be three wobbly young planets orbiting it. These "crazy kids" seem to be colliding with smaller objects, which of course stirs up cosmic dust. These objects are thought to be similar to comets or the same objects we have in our own Kuiper Belt. Around the same time these were discovered, a planet was found to be orbiting the star Formalhaut, which is in the constellation Pisces. Spitzer had been used to image the planetary debris around Fomalhaut, and astronomers were not sure whether Spitzer could "see" a distance five times further. However it appears that Spitzer was successful and snagged an image of HR 8799 and the cloud of dust being kicked up by the wobbly planets. It is thought that Jupiter and Saturn were quite wobbly before becoming established in their orbits and may have thrown all kinds of objects towards Earth, including comets or other icy objects. During the period called "late heavy bombardment", there could have been several of those objects crashing into Earth, which may be where the planet got its initial water supply.

The Chandra X-ray telescope has also been recently noted for a big discovery; it would seem that the neutron star in the Casseiopeia A supernovae remnant has a thin carbon atmosphere. This marks the very first time the composition of a neutron star's atmosphere has been identified. When Cas A was first imaged by Chandra ten years ago, the object at the center appeared to be an average neutron star; however, it did not emit any X-ray or rado signals. Several computer models of different scenarios were run, and it wasn't until the model featuring the carbon atmosphere was applied that the team realized the star was behaving the same way as the star in the model; it was unable to display any changes in its brightness as it rotated. The atmosphere was only estimated to be about four inches thick, and most neutron starts average around fourteen or fifteen miles across. That may seem like a puny atmosphere but you have to remember that it has been compressed by gravity that is about 100 billion times stronger than that of Earth's. The relatively young age of Cas A brings up more questions, including some surrounding its currently weak magnetic field. Astronomers now wonder if, as neutron stars age, their magnetic fields become stronger or if stars like Cas A will have a weak magnetic field the rest of their lives and never become radio pulsars. Dare to be different, Cas A! :)

Keep your eyes to the sky and enjoy the view!
~Lisa C.
AccuWeather.com

Posted by Lisa Beightol on Thursday, November 05, 2009 8:32 AM
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