A Closer Look at the LkCa 15 Protoplanetary Disk

TL;DR

This study uses high-resolution 870 micron observations to analyze the dust structure of the LkCa 15 protoplanetary disk, revealing a large cavity with residual dust inside, suggesting potential planet formation activity.

Contribution

It provides detailed morphological modeling of the disk's dust emission, indicating a cavity and possible planetary companion, advancing understanding of disk structures and planet formation.

Findings

Detection of dust emission inside the cavity (~5 mJy)

Evidence for a large (40-50 AU) low optical depth cavity

Indications of a low-mass planetary companion near the cavity edge

Abstract

We present 870 micron observations of dust continuum emission from the LkCa 15 protoplanetary disk at high angular resolution (with a characteristic scale of 0.25" = 35 AU), obtained with the IRAM Plateau de Bure interferometer and supplemented by slightly lower resolution observations from the Submillimeter Array. We fit these data with simple morphological models to characterize the spectacular ring-like emission structure of this disk. Our analysis indicates that a small amount of 870 micron dust emission (~5 mJy) originates inside a large (40-50 AU radius) low optical depth cavity. This result can be interpreted either in the context of an abrupt decrease by a factor of ~5 in the radial distribution of millimeter-sized dust grains or as indirect evidence for a gap in the disk, in agreement with previous inferences from the unresolved infrared spectrum and scattered light images. A preliminary model focused on the latter possibility suggests the presence of a low-mass (planetary) companion, having properties commensurate with those inferred from the recent discovery of LkCa 15b.