Nov 28 2008
From The Space Library
A team of researchers led by Paul G. Kalas of the University of California at Berkeley announced in the journal Science that they had used NASA’s HST to take the first visible-light photograph of a planet outside our solar system. The planet, known as Fomalhaut b, circles the star Fomalhaut in the constellation Piscis Australis, 25 light-years from Earth. Planets are difficult to detect in visible light because their stars often outshine them. Therefore, astronomers usually discover planets indirectly, through the effects that they have on their stars as they pass by them. However, scientists had long suspected that a planet might exist in the ring of dust debris surrounding Fomalhaut. In 2004 they had used the coronograph in the High Resolution Camera on Hubble’s Advanced Camera for Surveys to photograph the debris ring. A second set of photographs, taken in 2006, had revealed that a dot of light visible in the photographs is an orbiting planet. Researchers estimated that Fomalhaut b is 100 million years old, has a mass equivalent to three Jupiter masses, and circles its star in an 872-year-long orbit.
NASA, “Hubble Directly Observes a Planet Orbiting Another Star,” news release 08-289, 13 November 2008, http://www.nasa.gov/home/hqnews/2008/nov/HQ_08-289_Hubble_planet.html (accessed 22 August 2011); David Overbye, “Now in Sight: Far-Off Planets,” New York Times, 14 November 2008; see also Paul Kalas et al., “Optical Images of an Exosolar Planet 25 Light-Years from Earth,” Science 322, no. 5906 (21 November 2008): 1345-1348.
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