Presentation #339.21 in the session “Stars, Brown Dwarfs, and Binaries”.
The faint 2MASS source J11550336-7919147 (hereafter J1155-7919B) is a curious young, low-mass object that was discovered via a Gaia DR2 search for wide companions to known members of the epsilon Cha Association (eCA; age ~5 Myr, distance ~100 pc; Dickson-Vandervelde et al. 2020a, BAAS, 52, 273.21). The object is comoving with the M-type eCA member 2MASS J11550485-7919108 (J1155-7919A), at projected separation ~590 au. The companion, J1155-7919B, was originally suspected to be of substellar mass, and most likely a giant planet, based on its very low inferred luminosity and red Gaia-to-2MASS colors (Dickson-Vandervelde et al. 2020b, RNAAS, 4, 25). Follow-up spectroscopy with the Magellan FIRE instrument revealed a different, more likely scenario: J1155-7919B may be a low-mass star or a brown dwarf that is orbited by, and actively accreting from, a dusty disk viewed nearly edge-on. We present the observational evidence for this alternative model describing J1155-7919B.