Very Large Telescope observations of Gomez’s Hamburger: Insights into a young protoplanet candidate

Quote :: Planets are thought to form in the gas and dust disks around young stars. In particular, it has been proposed that giant planets can
form via gravitational instability of massive extended disks around intermediate mass stars. However, direct observations to constrain
this mechanism lack. We have spatially resolved the 8.6 and 11.2 µm emission of a massive edge on protoplanetary disk around an A
star, Gomez’s Hamburger (GoHam), using VISIR at the Very Large Telescope. A compact region situated at a projected distance of
350 ± 50 AU South of the central star is found to have a reduced emission. This asymmetry is fully consistent with the presence of
a cold density structure, or clump, identified in earlier CO observations, and we derive physical characteristics consistent with those
observations: a mass of 0.8-11.4 Jupiter masses (for a dust to gas mass ratio of 0.01), a radius of the order of 102
astronomical units,
a local density of the order of 107
cm−3
. Based on this evidence, we argue that this clump, which we call GoHam b, is a promising
candidate for a young protoplanet formed by gravitational instability, that could be representative of the precursors of massive planets
observed around A stars, like HR 8799 or Beta-pictoris. Further studies at high angular resolution are needed to better constrain the
physical properties of this object in order to confirm this proposal.

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