The brown dwarf population in the star forming region NGC2264

TL;DR

This study conducts a comprehensive multi-wavelength survey of NGC2264 to identify and analyze its young brown dwarf population, revealing their characteristics, rotation periods, and variability indicative of ongoing accretion.

Contribution

It presents the first extensive identification and characterization of brown dwarf candidates in NGC2264 using multi-epoch, multi-wavelength data and Gaia astrometry.

Findings

Identified 429 brown dwarf candidates with masses from 0.01 to 0.08 solar masses.

Measured rotation periods for 15 brown dwarf candidates, ranging from hours to days.

Detected high variability in some candidates, indicating ongoing disc accretion.

Abstract

The brown dwarf population in the canonical star forming region NGC2264 is so far poorly explored. We present a deep, multi-wavelength, multi-epoch survey of the star forming cluster NGC2264, aimed to identify young brown dwarf candidates in this region. Using criteria including optical/near-infrared colours, variability, Spitzer mid-infrared colour excess, extinction, and Gaia parallax and proper motion (in order of relevance), we select 902 faint red sources with indicators of youth. Within this sample we identify 429 brown dwarf candidates based on their infrared colours. The brown dwarf candidates are estimated to span a mass range from 0.01 to 0.08$M_{\odot}$. We find rotation periods for 44 sources, 15 of which are brown dwarf candidates, ranging from 3.6 hours to 6.5 days. A subset of 38 brown dwarf candidates show high level irregular variability indicative of ongoing disc accretion, similar to the behaviour of young stars.