There is a sophisticated story about Dagon, aka Fomalhaut b. The exoplanet was first discovered in 2008 in the data collected by Hubble Space Telescope between 2004 and 2006. Still, it took scientists another four years to confirm that the object located at 25 light-years away actually existed.
The fairest definition of Dagon would be an extrasolar object orbiting the star Fomalhaut in the constellation of Piscis Austrinus. It was a candidate planet, confirmed at some point, and now again denied. The name Dagon was given by the public. Dagon was a fertility god in Ebla, Assyria, Ugarit, and among the Amorites.
Dagon’s identity disorder
One of the first theories about Dagon was that it wasn’t a planet but the recent remnant of a collision between comet-to-asteroid-sized bodies. It was a much too young planet not to emit infrared radiation. And yet, Dagon didn’t emit infrared radiation at all. Its age wasn’t consistent with the much too bright blue optical wavelengths neither. It also didn’t gravitationally affect the debris ring surrounding the host planet.
Still, despite the evidence consistent with this belief, there was evidence that allowed the theory to be contested. Evidence (as much as the impossibility to believe that such a rare event could be observed) led Fomalhaut b to be recognized as the planet it wasn’t.
The old upset
A recent visit to Hubble’s old data revealed the unbelievable: back in 2014, Dagon went missing from its place. This together with the initial surprise of an exoplanet being observable in visible light became the proof that Dagon was not a planet. It was that very rare event caught on camera by Hubble: the collision of two visible light.
“These collisions are exceedingly rare and so this is a big deal that we actually get to see one. We believe that we were at the right place at the right time to have witnessed such an unlikely event with the Hubble Space Telescope,” said astronomer András Gáspár of the University of Arizona, about the exoplanet.