Archive for November 27, 2009

Spire Spectra

Posted in The Universe and Stuff with tags , , , , , , on November 27, 2009 by telescoper

OK, so it turns out I lied about not posting today. It’s not because I’m a dishonest professor, though. It’s just that I couldn’t resist drawing your attention to the new results that have just been released by the European Space Agency. To whet your appetite, have a shufty at this exquisite far infrared spectrum of the star VY Canis Majoris taken using the SPIRE instrument for which Cardiff is the lead institute.

VY Canis Majoris (VY CMa) is a red hypergiant, an enormous evolved star located in the constellation Canis Major. With a radius 2600 times that of the Sun, it is the largest known star and it is also one of the most luminous stars known. It is located about 4900 light years away from Earth, has a luminosity in excess of 100,000  solar luminosities, and a mass in the range 30-40 solar masses.

The shell of gas it has ejected displays a complex structure, the so-created circumstellar envelope is among the most remarkable chemical laboratories known in the universe, creating a rich set of organic and inorganic molecules and dust species. Through stellar winds, these inorganic and organic compounds are injected into the interstellar medium, from which new stars orbited by new planets may form. Most of the carbon supporting life on planet Earth was probably made by this kind of evolved star. VY CMa is close to the end of its life and could explode as a supernova at any time.

Spectroscopic results may be a bit less photogenic than pretty pictures, but they often yield much more physically relevant information than simple images. As I’ve mentioned before, it is in spectroscopy where we find the difference between astronomy and astrophysics (or, less politely, between stamp collecting and science).  In this case the spectrum gives a detailed breakdown of the chemical mixture present in the matter ejected by this star.

You can find other stunning examples of Herschel’s infrared spectroscopic capabilities here and you can read more about the involvement of Cardiff astronomers in these stunning new science results on our own pages here.

There’s also a story on the BBC Website.

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