A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus

TL;DR

This study provides detailed submillimeter observations of circumstellar disks around young stars in $ ho$ Ophiuchus, compares them with Taurus-Auriga, and establishes benchmark disk properties relevant for understanding early planet formation.

Contribution

It offers the first comprehensive submillimeter dataset for $ ho$ Ophiuchus and compares disk properties across two star-forming regions, highlighting their similarities and evolution.

Findings

Disk masses are around 0.005 solar masses.

Disk-to-star mass ratio is approximately 1%.

Submillimeter spectral index $eta$ suggests particle growth.

Abstract

We present new multiwavelength submillimeter continuum measurements of the circumstellar dust around 48 young stars in the $\rho$ Ophiuchus dark clouds. Supplemented with previous 1.3 mm observations of an additional 99 objects from the literature, the statistical distributions of disk masses and submillimeter colors are calculated and compared to those in the Taurus-Auriga region. These basic submillimeter properties of young stellar objects in both environments are shown to be essentially identical. As with their Taurus counterparts, the $\rho$ Oph circumstellar dust properties are shown to evolve along an empirical evolution sequence based on the infrared spectral energy distribution. The combined $\rho$ Oph and Taurus Class II samples (173 sources) are used to set benchmark values for basic outer disk characteristics: M_disk ~ 0.005 solar masses, M_disk/M_star ~ 1%, and $\alpha$ ~ 2 (where $F_{\nu} \propto \nu^{\alpha}$ between 350 microns and 1.3 mm). The precision of these numbers are addressed in the context of substantial solid particle growth in the earliest stages of the planet formation process. There is some circumstantial evidence that disk masses inferred from submillimeter emission may be under-estimated by up to an order of magnitude.