SIMBAD references

2010AJ....140.1486L - Astron. J., 140, 1486-1499 (2010/November-0)

A widely separated, highly occluded companion to the nearby low-mass T Tauri star TWA 30.


Abstract (from CDS):

We report the discovery of TWA 30B, a wide (∼3400 AU), co-moving M dwarf companion to the nearby (∼42 pc) young star TWA 30. Companionship is confirmed from their statistically consistent proper motions and radial velocities (RVs), as well as a chance alignment probability of only 0.08%. Like TWA 30A, the spectrum of TWA 30B shows signatures of an actively accreting disk (H I and alkali line emission) and forbidden emission lines tracing outflowing material ([O I], [O II], [O III], [S II], and [N II]). We have also detected [C I] emission in the optical data, marking the first such detection of this line in a pre-main-sequence star. Negligible RV shifts in the emission lines relative to the stellar frame of rest (ΔV ≲ 30 km/s) indicate that the outflows are viewed in the plane of the sky and that the corresponding circumstellar disk is viewed edge-on. Indeed, TWA 30B appears to be heavily obscured by its disk, given that it is 5 mag fainter than TWA 30A at K band despite having a slightly earlier spectral type (M4 versus M5). The near-infrared spectrum of TWA 30B also evinces an excess that varies on day timescales, with colors that follow classical T Tauri tracks as opposed to variable reddening (as is the case for TWA 30A). Multi-epoch data show this excess to be well modeled by a black body component with temperatures ranging from 630 to 880 K and emitting areas that scale inversely with the temperature. The variable excess may arise from disk structure such as a rim or a warp at the inner disk edge located at a radial distance of ∼3-5 R. As the second and third closest actively accreting and outflowing stars to the Sun (after TWA 3), TWA 30AB presents an ideal system for a detailed study of star and planetary formation processes at the low-mass end of the hydrogen-burning spectrum.

Abstract Copyright:

Journal keyword(s): brown dwarfs - circumstellar matter - open clusters and associations: individual: TW Hydrae Association - stars: evolution - stars: individual (2MASS J11321822-3018316, TWA 30A, TWA 30B) - stars: low-mass - stars: pre-main sequence

CDS comments: In introduction SSSPM J1102-3159 is a misprint for SSSPM J1102-3431.

Simbad objects: 28

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