May 4, 2011 at 9:57 AM ET
Two complementary views of the so-called Meathook Galaxy, released today, show how astronomers are piecing together the history of this lopsided group of stars.
The galaxy, located about 50 million light years away in the southern constellation Volans (The Flying Fish), is recognized for its asymmetrical spiral arms. One is tightly folded in on itself and host to a recent supernova, and the other is dotted with new star formation and extends far out from the nucleus.
The broa- view image above was taken by the Wide Field Imager the MPG/ESO 2.2-meter telescope at La Silla, Chile. It clearly shows the double hook shape that gives NGC 2442, as it the galaxy is officially known, its nickname.
The lopsided appearance is thought to be due to the gravitational interactions of another galaxy, though the culprit remains unknown, the European Space Agency noted in an image advisory. This interaction is probably responsible for an episode of recent star formation, seen as the patches of pink and red, particularly in the longer of the two spiral arms.
These colors come from hydrogen gas in star forming regions, ESA explains. As the powerful radiation of newborn stars excites the gas in the clouds they formed from, it glows in a bright shade of red.
The close-up view from the Hubble Space Telescope focuses on the nucleus of the Meathook and the more compact of its two spiral arms. Not seen in the image is a massive star that exploded at the end of its life in a supernova, witnessed in 1999. By comparing older ground-based observations, previous Hubble images and these made in 2006, astronomers have been able to study the details of the star's violent death. By the time this image was made, the supernova had faded.
John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).