An ALMA Disk Mass for the Candidate Protoplanetary Companion to FW Tau

Adam L. Kraus; Sean M. Andrews; Brendan P. Bowler; Gregory Herczeg; Michael J. Ireland; Michael C. Liu; Stanimir Metchev; Kelle L. Cruz

doi:10.1088/2041-8205/798/1/l23

arXiv · 1412.2175

An ALMA Disk Mass for the Candidate Protoplanetary Companion to FW Tau

Adam L. Kraus·Sean M. Andrews·Brendan P. Bowler·Gregory Herczeg·Michael J. Ireland·Michael C. Liu·Stanimir Metchev·Kelle L. Cruz

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Abstract

We present ALMA observations of the FW Tau system, a close binary pair of M5 stars with a wide-orbit (300 AU projected separation) substellar companion. The companion is extremely faint and red in the optical and near-infrared, but boasts a weak far-infrared excess and optical/near-infrared emission lines indicative of a primordial accretion disk of gas and dust. The component-resolved 1.3 mm continuum emission is found to be associated only with the companion, with a flux (1.78 +/- 0.03 mJy) that indicates a dust mass of 1-2 M_Earth. While this mass reservoir is insufficient to form a giant planet, it is more than sufficient to produce an analog of the Kepler-42 exoplanetary system or the Galilean satellites. The mass and geometry of the disk-bearing FW Tau companion remains unclear. Near-infrared spectroscopy shows deep water bands that indicate a spectral type later than M5, but substantial veiling prevents a more accurate determination of the effective temperature (and hence mass). Both a disk-bearing "planetary-mass" companion seen in direct light or a brown dwarf tertiary viewed in light scattered by an edge-on disk or envelope remain possibilities.

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Adam L. Kraus, Sean M. Andrews, Brendan P. Bowler, Gregory Herczeg, Michael J. Ireland, Michael C. Liu, Stanimir Metchev, Kelle L. Cruz. 2014-12-05. An ALMA Disk Mass for the Candidate Protoplanetary Companion to FW Tau. https://doi.org/10.1088/2041-8205/798/1/l23

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