A Novel Survey for Young Substellar Objects with the W-band filter III: Searching for very low mass brown dwarfs in Serpens South and Serpens Core

TL;DR

This study introduces a new photometric method using the W-band filter to identify very low-mass brown dwarfs in the Serpens star-forming region, confirming several candidates and discovering a binary system.

Contribution

The paper presents a novel W-band photometric technique for detecting young, low-mass substellar objects and applies it to Serpens South and Serpens Core, including spectroscopic confirmation and binary discovery.

Findings

Identified three new low-mass candidate members with spectral types M7-M8, M5-L0, M5-M6.5.

Discovered a binary system with components of spectral types M7-M8 and M8-M9.

Estimated masses of candidates to be less than 0.12 solar masses.

Abstract

We present CFHT photometry and IRTF spectroscopy of low-mass candidate members of Serpens South and Serpens Core ($\sim$430 pc, $\sim$0.5 Myr), identified using a novel combination of photometric filters, known as the W-band method. We report SC182952+011618, SS182959-020335 and SS183032-021028 as young, low-mass Serpens candidate members, with spectral types in the range M7-M8, M5-L0 and M5-M6.5 respectively. Best-fit effective temperatures and luminosities imply masses of $<$ 0.12M$_{\odot}$ for all three candidate cluster members. We also present Hubble Space Telescope imaging data (F127M, F139M and F850LP) for six targets in Serpens South. We report the discovery of the binary system SS183044-020918AB. The binary components are separated by $\approx$45 AU, with spectral types of M7-M8 and M8-M9, and masses of 0.08-0.1 and 0.05-0.07M$_{\odot}$. We discuss the effects of high dust attenuation on the reliability of our analysis, as well as the presence of reddened background stars in our photometric sample.