New HST data and modeling reveal a massive planetesimal collision around Fomalhaut

Understand

The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008.

• However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the infrared, and its orbit appears to cross the debris ring around the star without the expected gravitational perturbations.
• We revisit previously published data and analyze additional Hubble Space Telescope (HST) data, finding that the source is likely on a radial trajectory and has faded and become extended.
• Dynamical and collisional modeling of a recently produced dust cloud yields results consistent with the observations.