The nature and even the existence of a putative planet-mass companion ( ” Fomalhaut b ” ) to Fomalhaut has been debated since 2008 .
In the present paper we reanalyze the multi-epoch ACS/STIS/WFC3 Hubble Space Telescope ( HST ) optical/near infrared images on which the discovery and some other claims were based .
We confirm that the HST images do reveal an object in orbit around Fomalhaut but the detailed results from our analysis differ in some ways from previous discussions .
In particular , we do not confirm flux variability over a two-year interval at 0.6 \mu m wavelength and we detect Fomalhaut b for the first time at the short wavelength of 0.43 \mu m. We find that the HST image of Fomalhaut b at 0.8 \mu m may be extended beyond the PSF .
We can not determine from our astrometry if Fomalhaut b will cross or not the dust ring .
The optical through mid-infrared spectral energy distribution ( SED ) of Fomalhaut b can not be explained as due to direct or scattered radiation from a massive planet .
We consider two models to explain the SED : ( 1 ) a large circumplanetary disk around an unseen planet and ( 2 ) the aftermath of a collision during the past 50-150 years of two Kuiper Belt-like objects of radii \sim 50 km .