Determining the Physical Conditions of an Extremely Young Class 0 Circumbinary Disk around VLA 1623A

Abstract

We present a detailed analysis of high-resolution C 18 O (2–1), SO (8 8 –7 7 ), CO (3–2), and DCO + (3–2) data obtained by the Atacama Large Millimeter/submillimeter Array toward a class 0 Keplerian circumbinary disk around VLA 1623A, which represents one of the most complete analyses toward 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 VLA 1623B. The discovery of two outflow cavity walls at the same position traveling at different velocities suggests that the two outflows from both VLA 1623A and VLA 1623B are on top of each other in the plane of the sky. Our detailed flat and flared disk modeling shows that Cycle 2 C 18 O J  = 2–1 data are inconsistent with the combined binary mass of 0.2 M ⊙ , as suggested by early Cycle 0 studies. The combined binary mass for VLA 1623A should be modified to 0.3–0.5 M ⊙ .