page_title: Fomalhaut b
section_title: Initial discovery by Hubble
hierarchical_section_title: Fomalhaut b / Initial discovery by Hubble
caption_attribution_description: Fomalhaut, HD 216956, Fomalhaut b
context_page_description: Fomalhaut b, formally named Dagon, is a confirmed, directly imaged extrasolar object and candidate planet orbiting the A-type main-sequence star Fomalhaut, approximately 25 light-years away in the constellation of Piscis Austrinus. The object was initially announced in 2008 and confirmed as real in 2012 from images taken with the Advanced Camera for Surveys on the Hubble Space Telescope and, according to calculations reported in January 2013, has a 1,700-year, highly elliptical orbit. It has a periastron of 7.4 billion km and an apastron of about 44 billion km. As of May 25, 2013 it is 110 AU from its parent star.
  The true nature of Fomalhaut b is the subject of significant debate. Fomalhaut b was initially identified as one of the first exoplanets to be directly imaged: its detection was attributed to reflected light from circumplanetary material and thermal emission from a jovian planet atmosphere. Fomalhaut b has subsequently been described as a low-mass planet whose surrounding dust cloud is entirely responsible for its detection or, most recently, debris from a collision of asteroids instead.
context_section_description: The existence of a massive planet orbiting Fomalhaut was first inferred from Hubble observations published in 2005 that resolved the structure of Fomalhaut's massive, cold debris disk (or dust belt/ring).  The belt is not centered on the star, and has a sharper inner boundary than would normally be expected.  A massive planet on a wide orbit but located interior to this debris ring could clear out parent bodies and dust in its vicinity, leaving the ring appearing to have a sharp inner edge and making it appear offset from the star.
  In May 2008, Paul Kalas, James Graham and their collaborators identified Fomalhaut b from Hubble/ACS images taken in 2004 and 2006 at visible wavelengths (i.e. 0.6 and 0.8 μm). NASA released the composite discovery photograph on November 13, 2008, coinciding with the publication of Kalas et al. discovery in Science.
  Kalas remarked, "It's a profound and overwhelming experience to lay eyes on a planet never before seen. I nearly had a heart attack at the end of May when I confirmed that Fomalhaut b orbits its parent star." In the image, the bright outer oval band is the dust ring, while the features inside of this band represent noise from scattered starlight.
caption: Comparison between the Solar System and the system around Fomalhaut
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