A Keplerian gaseous disk around the B0 star R Mon

TL;DR

This paper reports high-resolution observations of a Keplerian gaseous disk around the massive B0 star R Mon, providing clear evidence of such disks around massive stars and comparing their properties to those around T Tauri stars.

Contribution

It presents the first clear evidence of a Keplerian disk around a massive star, with detailed measurements of its mass and size, highlighting similarities to disks around lower-mass stars.

Findings

Disk mass estimated at 0.007 Msun

Outer radius less than 150 AU

Keplerian rotation confirmed around R Mon

Abstract

We present high-angular resolution observations of the circumstellar disk around the massive Herbig Be star R Mon (M~8 Msun) in the continuum at 2.7mm and 1.3mm and the CO 1->0 and 2->1 rotational lines. Based on the new 1.3mm continuum image we estimate a disk mass (gas+dust) of 0.007 Msun and an outer radius of <150 AU. Our CO images are consistent with the existence of a Keplerian rotating gaseous disk around this star. Up to our knowledge, this is the most clear evidence for the existence of Keplerian disks around massive stars reported thus far. The mass and physical characteristics of this disk are similar to thoseof the more evolved T Tauri stars and indicate a shorter timescale for the evolution and dispersal of circumstellar disks around massive stars which lose most of their mass before the star becomes visible.