Why are astronomers excited about the first directly obtained visible light spectrum – or rainbow array of visible colors – bounced from the surface of an exoplanet?
The exoplanet 51 Pegasi b – a hot Jupiter, located some 50 light-years from Earth in the direction of our constellation Pegasus – will forever be remembered as the first confirmed exoplanet found orbiting an ordinary star like our sun. That was in 1995, and now more than 1900 exoplanets in 1200 planetary systems have been confirmed, and billions more are suspected in our Milky Way. In a giant step forward in exploring exoplanets, astronomers in Chile announced on April 22, 2015 that they used 51 Pegasi b for another first, the first-ever direct detection of a spectrum of visible light reflected off an exoplanet’s surface. They’re excited! And here’s why.
This first suggests that more will follow, just as the discovery of thousands more exoplanets followed the discovery of 51 Pegasi b. It means our technology has advanced to the point where the direct detection of visible light spectra from exoplanets has become possible. The gathering of light spectra is a powerful tool for astronomers. For example, because the spectra of objects in space are in some cases crossed with dark absorption lines – created by cold gases through which the light has passed – this tool will eventually enable astronomers to know what chemical elements are present in the atmospheres of exoplanets like 51 Pegasi b.
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http://interstellar-news.blogspot.com/2015/04/first-visible-light-spectrum-from.html
