Mon. Not. R. Astron. Soc. 453, 2126–2132 (2015)

Low-mass stars and high-mass stars have distinctly different formation processes, but what of intermediate-mass stars? HD 100546 is such a star, and the recent discovery of up to two planetary objects makes this star system our closest 'solar system'. It is an ideal source for Ignacio Mendigutía and collaborators, who used the Very Large Telescope Interferometer in Chile to study the conditions for planet formation around the young star.

The authors focused on the high-excitation hydrogen emission line known as Br γ (at wavelength 2.166 μm), which is a standard tracer for a star's accretion of matter. HD 100546 is unusual in that it is surrounded by an inner disk of gas and dust, which is separated from an extensive outer disk by a large gap. Their estimated mass accretion rate of the inner disk turns out to be greater than the amount of material that the gaseous inner disk can provide in a year, so Mendigutía et al. suggest that the gas within the inner disk must be replenished, perhaps by planet-boosted flows from the outer disk.