A Multi-ringed, Modestly Inclined Protoplanetary Disk around AA Tau

作者：Loomis Ryan A; Oberg Karin I; Andrews Sean M; MacGregor Meredith A

来源：Astrophysical Journal, 2017, 840(1): 23.

DOI：10.3847/1538-4357/aa6c63

<jats:title>Abstract</jats:title>
<jats:p>AA Tau is the archetype for a class of stars with a peculiar periodic photometric variability thought to be related to a warped inner disk structure with a nearly edge-on viewing geometry. We present high resolution (∼0.″2) ALMA observations of the 0.87 and 1.3 mm dust continuum emission from the disk around AA Tau. These data reveal an evenly spaced three-ringed emission structure, with distinct peaks at 0.″34, 0.″66, and 0.″99, all viewed at a modest inclination of 59.°1 ± 0.°3 (decidedly not edge-on). In addition to this ringed substructure, we find non-axisymmetric features, including a “bridge” of emission that connects opposite sides of the innermost ring. We speculate on the nature of this “bridge” in light of accompanying observations of HCO<jats:sup>+</jats:sup> and <jats:sup>13</jats:sup>CO (<jats:italic>J</jats:italic> = 3–2) line emission. The HCO<jats:sup>+</jats:sup> emission is bright interior to the innermost dust ring, with a projected velocity field that appears rotated with respect to the resolved disk geometry, indicating the presence of a warp or inward radial flow. We suggest that the continuum bridge and HCO<jats:sup>+</jats:sup> line kinematics could originate from gap-crossing accretion streams, which may be responsible for the long-duration dimming of optical light from AA Tau.</jats:p>

• 出版日期2017-5-1