AN ALMA DISK MASS FOR THE CANDIDATE PROTOPLANETARY COMPANION TO FW TAU
AN ALMA DISK MASS FOR THE CANDIDATE PROTOPLANETARY COMPANION TO FW TAU
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DOI：
10.1088/2041-8205/798/1/l23
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发表时间：
2014-12
期刊：
影响因子：
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通讯作者：
A. Kraus;S. Andrews;B. Bowler;G. Herczeg;M. Ireland;Michael C. Liu;S. Metchev;K. Cruz
中科院分区：
文献类型：
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作者：
A. Kraus;S. Andrews;B. Bowler;G. Herczeg;M. Ireland;Michael C. Liu;S. Metchev;K. Cruz
我们目前的阿尔马观测FW Tau系统，一个密切的双星对M5星与宽轨道（300 Au投影分离）的亚恒星同伴。这颗伴星在光学和近红外波段非常微弱和红色，但拥有微弱的远红外过量和光学/近红外发射线，表明它是一个由气体和尘埃组成的原始吸积盘。分量分辨的1.3毫米连续辐射被发现只与伴星有关，其通量（1.78 ± 0.03 mJy）表明尘埃质量为1-2 M。虽然这个质量库不足以形成一颗巨大的行星，但它足以产生一个类似于开普勒-42系外行星系统或伽利略卫星的系统。带着圆盘的FW Tau伴星的质量和几何形状仍然不清楚。近红外光谱显示深水带，表明光谱类型晚于M5，但大量的面纱阻止了更准确地确定有效温度（因此质量）。无论是在直射光下看到的一个带有“行星质量”的伴星，还是在边缘上的圆盘或封套散射的光下看到的一个棕矮星，都仍然是可能的。
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⊕. 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.