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Investigating 2M1155-79B: A Nearby, Young, Low-mass Star Actively Accreting from a Nearly Edge-on, Dusty Disk

Abstract : We investigate the nature of an unusually faint member of the ϵ Cha association (D ~ 100 pc, age ~5 Myr), the nearest region of star formation of age <8 Myr. This object, 2MASS J11550336-7919147 (2M1155-79B), is a wide-separation (~580 au), comoving companion to low-mass (M3) ϵ Cha association member 2MASS J11550485-7919108 (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 He I 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. This would place 2M1155-79B among the rare group of nearby (D ≲ 100 pc), young (age <10 Myr) mid-M stars that are orbited by and accreting from highly inclined protoplanetary disks. Like these systems, the 2M1155-79B system is a particularly promising subject for studies of star and planet formation around low-mass stars.
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Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Saturday, November 19, 2022 - 8:59:48 AM
Last modification on : Sunday, November 20, 2022 - 3:05:02 AM


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D. Annie Dickson-Vandervelde, Joel H. Kastner, Jonathan Gagné, Adam C. Schneider, Jacqueline Faherty, et al.. Investigating 2M1155-79B: A Nearby, Young, Low-mass Star Actively Accreting from a Nearly Edge-on, Dusty Disk. The Astronomical Journal, 2022, 164, ⟨10.3847/1538-3881/ac9674⟩. ⟨insu-03860261⟩



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