Evidence for a Photoevaporated Circumbinary Disk in Orion

TL;DR

This paper reports the first direct observation of a photoevaporated circumbinary disk in Orion, featuring a wide binary system with a low-mass brown dwarf pair still accreting and embedded in its disk.

Contribution

It provides the first observational evidence of a photoevaporated circumbinary disk with a wide substellar binary in Orion.

Findings

Detected a binary system with 0.15" separation (~60 AU) in Orion.

Identified the primary component as a ~0.04 M_ brown dwarf with ongoing accretion.

First evidence of a wide, accreting substellar pair within a photoevaporated circumbinary disk.

Abstract

We have found a photoevaporated disk in the Orion Nebula that includes a wide binary. HST/ACS observations of the proplyd 124-132 show two point-like sources separated by 0".15, or about 60 AU at the distance of Orion. The two sources have nearly identical I and z magnitudes. We analyze the brightest component, Source N, comparing the observed magnitudes with those predicted using a 1 Myr Baraffe/NEXTGEN isochrone with different accretion luminosities and extinctions. We find that a low mass (\simeq 0.04 M_\odot) brown dwarf ~1 Myr old with mass accretion rate \log\dot{M}\simeq -10.3, typical for objects of this mass, and about 2 magnitudes of visual extinction provides the best fit to the data. This is the first observation of a circumbinary disk undergoing photoevaporation and, if confirmed by spectroscopic observations, the first direct detection of a wide substellar pair still accreting and enshrouded in its circumbinary disk.