Comets Predict the Presence of an Exoplanet

Astronomers recently discovered a large cloud of carbon monoxide gas surrounding Beta Pictoris, a 20 million year old star system located 63 ly from Earth. Because ultraviolet radiation from the central and surrounding stars should have destroyed this layer of carbon monoxide a long time ago, scientists believe it is being replenished by the collision of comets. According to their calculations, one large comet must be destroyed every five minutes in order to maintain the CO disk around Beta Pictoris!

In order to detect the carbon monoxide disk, astronomers used the Atacama Large Millimeter/submillimeter Array in Chile to obtain spectra like those we discussed earlier in the course. The data showed that a major portion of the carbon monoxide was concentrated in one region, which gives rise to two different explanations since Beta Pictoris was observed side-on. The prominent one is that there are actually two concentrated clouds of CO, which would require the presence of a to-be-found exoplanet (Beta Pictoris already contains the planet Beta Pictoris b). This exoplanet would need to be around the size of Saturn and orbit Beta Pictoris at a larger distance than Beta Pictoris b to essentially concentrate the swarm of comets between the two planets. This is another method for finding exoplanets we can add to our list!

The video below also gives a great summary with some of the data astronomers found.

http://www.space.com/24975-colliding-comets-may-be-hiding-alien-planet-video.html

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