# Determining the physical conditions of extremely young Class 0 circumbinary disk around VLA1623A

## TL;DR

This study provides a comprehensive analysis of the physical conditions in a very young Class 0 circumbinary disk around VLA1623A using high-resolution ALMA data, revealing complex accretion flows, shocks, and revised mass estimates.

## Contribution

It offers the first detailed analysis of a Class 0 Keplerian circumbinary disk with multi-molecular data, identifying accretion flows, shocks, and updating the binary mass estimate.

## Key findings

- Identification of anisotropic accretion flows feeding the disk.
- Detection of shock interactions between disk, flows, and outflows.
- Revised binary mass estimate to 0.3-0.5 Msun.

## Abstract

We present detailed analysis of high-resolution C18O (2-1), SO (88-77), CO (3-2) and DCO+ (3-2) data obtained by the Atacama Large Millimeter/sub-millimeter Array (ALMA) towards a Class 0 Keplerian circumbinary disk around VLA1623A, which represents one of the most complete analysis towards a Class 0 source. From the dendrogram analysis, we identified several accretion flows feeding the circumbinary disk in a highly anisotropic manner. Stream-like SO emission around the circumbinary disk reveals the complicated shocks caused by the interactions between the disk, accretion flows and outflows. A wall-like structure is discovered south of VLA1623B. The discovery of two outflow cavity walls at the same position traveling at different velocities suggests the two outflows from both VLA1623A and VLA1623B overlays on top of each other in the plane of sky. Our detailed flat and flared disk modeling shows that Cycle 2 C18O J = 2-1 data is inconsistent with the combined binary mass of 0.2 Msun as suggested by early Cycle 0 studies. The combined binary mass for VLA1623A should be modified to 0.3 ~ 0.5 Msun.