Extended Millimeter Emission in the HD 141569 Circumstellar Disk Detected with ALMA

TL;DR

This study uses ALMA data to reveal extended millimeter emission in the HD 141569 disk, modeling its two-component structure and analyzing grain size distribution evolution over 5 million years.

Contribution

First detailed multi-frequency modeling of the HD 141569 disk revealing a two-component structure with distinct grain size distributions.

Findings

Inner disk spans 16-45 au with spectral index 1.81

Outer disk spans 95-300 au with spectral index 2.28

Outer disk has a steeper, more evolved grain size distribution

Abstract

We present archival ALMA observations of the HD 141569 circumstellar disk at 345, 230, and 100 GHz. These data detect extended millimeter emission that is exterior to the inner disk. We find through simultaneous visibility modeling of all three data sets that the system's morphology is described well by a two-component disk model. The inner disk ranges from approximately 16 to 45 au with a spectral index of 1.81 (q = 2.95) and the outer disk ranges from 95 to 300 au with a spectral index of 2.28 (q = 3.21). Azimuthally averaged radial emission profiles derived from the continuum images at each frequency show potential emission that is consistent with the visibility modeling. The analysis presented here shows that at ~5 Myr HD 141569's grain size distribution is steeper, and therefore more evolved, in the outer disk than in the inner disk.