![]() | Parts of this article (those related to the difference between the planetary and cloud debris models, and why most recent analysis does not place this object in a bound orbit around Fomalhaut) need to be updated.(March 2022) |
![]() Fomalhaut b as observed from 2004 to 2014. Previously thought to be an exoplanet, it is now known to be an expanding dust cloud. | |
Discovery | |
---|---|
Discovered by | Kalas et al.[1] |
Discovery site | Hubble Space Telescope |
Discovery date | November 13, 2008 |
Direct imaging | |
Orbital characteristics | |
Star | Fomalhaut |
Fomalhaut b, formally named Dagon (/ˈdeɪɡən/),[2] is a former candidate planet observed near the A-type main-sequence star Fomalhaut, approximately 25 light-years away in the constellation of Piscis Austrinus. The object's discovery was initially announced in 2008 and confirmed in 2012 via images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. Under the working hypothesis that the object was a planet, it was reported in January 2013[3][4] that it had a highly elliptical orbit with a period of 1,700 Earth years.[5] The object was one of those selected by the International Astronomical Union as part of NameExoWorlds, their public process for giving proper names to exoplanets.[6][7] The process involved public nomination and voting for the new name.[8] In December 2015, the IAU announced the winning name was Dagon.[9][10][11]
The planetary hypothesis has since fallen out of favor; more gathered data suggested a dust or debris cloud is far more likely, and the object was placed on an escape trajectory.[12] In 2023, a team of researchers used the James Webb Space Telescope's MIRI to probe the complex dust environment around the Fomalhaut. They discovered a new intermediate dust belt that might be shepherded by an unseen planet and suggested that the blob, Fomalhaut b, could've originated in this belt. The recent research of the Fomalhaut system used the JWST's NIRCam equipped with coronagraphs to probe the complex dust ring in different wavelengths of infrared light. The absence of detection in certain wavelengths support the idea that Fomalhaut b isn't a massive planet but rather a dust cloud resulting from a collision among planetesimals.[13][14]
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