NIR spectra of 2M1155-79A and B

This object, 2MASSJ11550336-7919147 (2M1155-79B), is a wide-separation (~580au), comoving companion to low-mass (M3) {epsilon}Cha association member 2MASSJ11550485-7919108 (2M1155-79A). We present near-infrared (NIR) spectra of both components, along with analysis of photometry from Gaia Early Data Release 3, the Two Micron All Sky Survey, the Vista Hemisphere Survey, and the Wide-field Infrared Survey Explorer (WISE).

The NIR spectrum of 2M1155-79B displays strong HeI 1.083 emission, a sign of active accretion and/or accretion-driven winds from a circumstellar disk. Analysis of WISE archival data reveals that the mid-infrared excess previously associated with 2M1155-79A instead originates from the disk surrounding 2M1155-79B. Based on these results, as well as radiative transfer modeling of its optical/IR spectral energy distribution, we conclude that 2M1155-79B is most likely a young, late M star that is partially obscured by, and actively accreting from, a nearly edge-on circumstellar disk.