A candidate circumbinary Keplerian disk in G35.20-0.74 N: A study with ALMA

TL;DR

This study presents ALMA observations revealing a candidate Keplerian disk around a high-mass star in G35.20-0.74 N, suggesting a binary system to explain the luminosity and mass estimates.

Contribution

First detection of a candidate Keplerian disk in G35.20-0.74 N using ALMA, indicating a possible binary system in a high-mass star forming region.

Findings

Keplerian disk with radius >2500 au and mass ~3 Msun

Central mass of ~18 Msun consistent with previous CO bandhead studies

Binary system hypothesis to explain luminosity and mass estimates

Abstract

We report on ALMA observations of continuum and molecular line emission with 0.4" resolution towards the high-mass star forming region G35.20-0.74 N. Two dense cores are detected in typical hot-core tracers, such as CH3CN, which reveal velocity gradients. In one of these cores, the velocity field can be fitted with an almost edge-on Keplerian disk rotating about a central mass of 18 Msun. This finding is consistent with the results of a recent study of the CO first overtone bandhead emission at 2.3mum towards G35.20-0.74 N. The disk radius and mass are >2500 au and 3 Msun. To reconcile the observed bolometric luminosity (3x10^4 Lsun) with the estimated stellar mass of 18 Msun, we propose that the latter is the total mass of a binary system.