# Accretion onto Planetary Mass Companions of Low-mass Young Stars

 Title Accretion onto Planetary Mass Companions of Low-mass Young Stars Publication Type Journal Article Year of Publication 2014 Authors Zhou, Y, Herczeg, G J, Kraus, A L, Metchev, S, Cruz, K L Journal \apjl Volume 783 Pagination L17 Keywords accretion, accretion disks, brown dwarfs, protoplanetary disks, stars: low-mass, stars: pre-main sequence Abstract {Measurements of accretion rates onto planetary mass objects may distinguish between different planet formation mechanisms, which predict different accretion histories. In this Letter, we use Hubble Space Telescope (HST)/WFC3 UVIS optical photometry to measure accretion rates onto three accreting objects, GSC 06214-00210 b, GQ Lup b, and DH Tau b, that are at the planet/brown dwarf boundary and are companions to solar mass stars. The excess optical emission in the excess accretion continuum yields mass accretion rates of 10$^{-9}$-10$^{-11}$ M $_{⊙}$ yr$^{-1}$ for these three objects. Their accretion rates are an order of magnitude higher than expected from the correlation between mass and accretion rates measured from the UV excess, which is applicable if these wide planetary mass companions formed by protostellar core fragmentation. The high accretion rates and large separation from the central star demonstrate the presence of massive disks around these objects. Models for the formation and evolution of wide planetary mass companions should account for their large accretion rates. High ratios of H{$\alpha$} luminosity over accretion luminosity for objects with low accretion rates suggest that searches for H{$\alpha$} emission may be an efficient way to find accreting planets. } DOI 10.1088/2041-8205/783/1/L17