MESAS: Measuring the Emission of Stellar Atmospheres at Submm/mm wavelengths

TL;DR

This paper presents observations and modeling of Sirius A's stellar atmosphere at submm/mm wavelengths to accurately characterize stellar emission, aiding the detection of debris disks around A-type stars.

Contribution

It introduces a PHOENIX atmospheric model for Sirius A based on multi-wavelength observations, serving as a template for other early A-type stars.

Findings

Model matches observed data well

Provides a reliable template for stellar emission

Supports detection of debris disks in unresolved systems

Abstract

In the early stages of planet formation, small dust grains grow to become mm sized particles in debris disks around stars. These disks can in principle be characterized by their emission at submillimeter and millimeter wavelengths. Determining both the occurrence and abundance of debris in unresolved circumstellar disks of A-type main-sequence stars requires that the stellar photospheric emission be accurately modeled. To better constrain the photospheric emission for such systems, we present observations of Sirius A, an A-type star with no known debris, from the JCMT, SMA, and VLA at 0.45, 0.85, 0.88, 1.3, 6.7, and 9.0 mm. We use these observations to inform a PHOENIX model of Sirius A's atmosphere. We find the model provides a good match to these data and can be used as a template for the submm/mm emission of other early A-type stars where unresolved debris may be present. The observations are part of an ongoing observational campaign entitled Measuring the Emission of Stellar Atmospheres at Submm/mm wavelengths (MESAS)