Researchers Discover Aging Blue Supergiant Star In Virgo Cluster

Researchers have discovered an aging blue supergiant star located far beyond our Milky Way Galaxy in the constellation Virgo.

AsianScientist (Apr. 16, 2013) – Researchers have discovered an aging blue supergiant star located far beyond our Milky Way Galaxy in the constellation Virgo.

Over 55 million years ago, IC 3418 emerged in an extremely wild environment, surrounded by intensely hot plasma at a million degrees Celsius and amid raging cyclone winds blowing at four million kilometers per hour.

A duo of astronomers, Dr. Youichi Ohyama, from the Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan, and Dr. Ananda Hota, from the UM-DAE Center for Excellence in the Basic Sciences, India, used the Subaru Telescope, the Canada-France-Hawaii-Telescope (CFHT), and NASA’s Galaxy Evolution Explorer (GALEX) to reveal unprecedented views of the star formation process.

The Virgo cluster, the nearest cluster of galaxies located about 55 million light-years from Earth in the constellation Virgo, is an ideal laboratory to study the fate of gas stripped from the main body of galaxies falling into the intra-cluster medium.

Does star formation take place in the clouds of stripped gas? If so, how? Dr. Ohyama and Dr. Hota focused on the trail of IC 3418 to explore a potentially new mode of star formation. Dr. Hota first spotted this galaxy in the GALEX data while he was doing his Ph.D. research seven years ago.

IC 3418 is a small galaxy falling into the Virgo cluster of galaxies at such a high speed (1,000 kilometers per second) that its blanket of cool gas strips off. As it passed through the cluster, its stripped-off cool gas formed a 55,500 light-years-long trail that looks very much like the water vapor condensation trail from a supersonic jet’s path.

Dr. Ohyama suspected that a tiny dot of light emission in the trail of IC 3418 might be different from other blobs of ultraviolet light emissions in the trail.

“When I first saw the spectrum, I was so puzzled, since it did not look like anything I had known of in extragalactic astronomy,” said Ohyama. Unlike typical star-forming regions, the telltale signs of stellar nurseries were missing.

Comparison with emissions from nearby stars made it clear that this massive, hot (O-type) star had passed its youth and was now aging; it was at a stage known as a blue supergiant star and would soon face its explosive death as a supernova.

“If our interpretations are correct, this is probably the farthest star ever discovered with spectroscopic observation. Since we only observed for a fraction of the night with the 8.2-meter Subaru Telescope, there is huge potential for stellar spectroscopy with extremely large telescopes, e.g., the Thirty Meter Telescope, being planned for the future. We look forward to that exciting time,” Ohyama said.

The article can be found at: Ohyama Y et al. (2013) Discovery of a Possibly Single Blue Supergiant Star in the Intra-Cluster Region of Virgo Cluster of Galaxies.

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Source: ; Photo: NASA/JPL-Caltech/SDSS.
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