Follow Friday & Weekly Stumbles For 2010-11-26

This week I recommend to follow @howellspace for lots of interesting tweets about astronomy and space. For more Twitter follow suggestions see our astronomy list @TheAstroBlog/astronomy

Weekly Stumbles:

Saturn Moon Has Oxygen Atmosphere
An oxygen atmosphere has been found on Saturn’s second largest moon, Rhea, astronomers announced Thursday—but don’t hold your breath for colonization opportunities. For one thing, the 932-mile-wide (1,500-kilometer-wide), ice-covered moon is more than 932 million miles (1.5 billion kilometers) from Earth. For another, the average surface temperature is -292 degrees Fahrenheit (-180 degrees Celsius). And at less than 62 miles (100 kilometers) thick, the newfound oxygen layer is so thin that, at Earthlike temperatures and pressure, Rhea’s entire atmosphere would fit in a single midsize building.

New ‘Alien Invader’ Star Clusters Found in Milky Way
As many as one quarter of the star clusters in our Milky Way — many more than previously thought — are invaders from other galaxies, according to a new study. The report also suggests there may be as many as six dwarf galaxies yet to be discovered within the Milky Way rather than the two that were previously confirmed.

Symbiotic Variable Star On the Verge of an Eruption?
November 23rd, astronomers from the Asiago Novae and Symbiotic Stars collaboration announced recent changes in the symbiotic variable star, AX Persei, could indicate the onset of a rare eruption of this system. The last major eruption took place between 1988 and1992. In the (northern hemisphere) spring of 2009, AX Per underwent a short outburst that was the first time since 1992 this star had experienced a bright phase. Now AX Per is on the rise again. This has tempted astronomers to speculate that another major eruption could be in the making.

Simulation casts doubt on origins of lunar water
The mystery of how the moon got its surface water has just got deeper, following the failure of an attempt to replicate the mechanism that was thought to produce it. Three separate space missions last year reported detecting a sheen of water only molecules thick over large parts of the moon’s surface. Many planetary scientists assumed the water was created when particles from the solar wind hit lunar soils, but this idea has now been thrown into doubt.

Pulsating Star Mystery Solved in Rare Alignment of Cepheid Variable and Another Star
By discovering the first double star where a pulsating Cepheid variable and another star pass in front of one another, an international team of astronomers has solved a decades-old mystery. The rare alignment of the orbits of the two stars in the double star system has allowed a measurement of the Cepheid mass with unprecedented accuracy. The new result shows that the prediction from stellar pulsation theory is spot on, while the prediction from stellar evolution theory is at odds with the new observations.

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