Accretion kinematics through the warped transition disk in HD142527 from resolved CO(6-5) observations

TL;DR

This study uses high-resolution CO(6-5) observations to analyze the warped structure and non-Keplerian gas kinematics in the HD142527 disk, revealing accretion flows and potential disk tearing influenced by a low-mass companion.

Contribution

It provides detailed insights into the physical structure and kinematics of the HD142527 disk, linking observed gas flows to theoretical models of disk tearing and companion-induced dynamics.

Findings

Residual gas in the cavity shows non-Keplerian, axisymmetric accretion.

Warp and radial flows suggest disk tearing possibly driven by a low-mass companion.

Azimuthal density variations are hinted but require further observation.

Abstract

The finding of residual gas in the large central cavity of the HD142527 disk motivates questions on the origin of its non-Keplerian kinematics, and possible connections with planet formation. We aim to understand the physical structure that underlies the intra-cavity gaseous flows, guided by new molecular-line data in CO(6-5) with unprecedented angular resolutions. Given the warped structure inferred from the identification of scattered-light shadows cast on the outer disk, the kinematics are consistent, to first order, with axisymmetric accretion onto the inner disk occurring at all azimuth. A steady-state accretion profile, fixed at the stellar accretion rate, explains the depth of the cavity as traced in CO isotopologues. The abrupt warp and evidence for near free-fall radial flows in HD 142527 resemble theoretical models for disk tearing, which could be driven by the reported low mass companion, whose orbit may be contained in the plane of the inner disk. The companion's high inclination with respect to the massive outer disk could drive Kozai oscillations over long time-scales; high-eccentricity periods may perhaps account for the large cavity. While shadowing by the tilted disk could imprint an azimuthal modulation in the molecular-line maps, further observations are required to ascertain the significance of azimuthal structure in the density field inside the cavity of HD142527.