SIMP J2154-1055: A New Low-Gravity L4$\beta$ Brown Dwarf Candidate Member of the Argus Association

TL;DR

This paper reports the discovery of a new low-gravity L4β brown dwarf candidate, SIMP J2154-1055, which may belong to the Argus association, potentially having a planetary mass if confirmed.

Contribution

The paper introduces a newly identified low-gravity brown dwarf candidate with potential membership in the Argus association, expanding understanding of young substellar objects.

Findings

Identified SIMP J2154-1055 as a low-gravity L4β brown dwarf candidate.

Estimated a planetary mass of approximately 10 Jupiter masses if it is a member of Argus.

Proposed further measurements to confirm its association with Argus.

Abstract

We present SIMP J21543454-1055308, a new L4$\beta$ brown dwarf identified in the Sondage Infrarouge de Mouvement Propre (SIMP) survey that displays signs of low gravity in its near-infrared spectrum. Using the Bayesian Analysis for Nearby Young AssociatioNs II (BANYAN II), we show that it is a candidate member of the Argus association, albeit with a 21% probability that it is a contaminant from the field. Measurements of radial velocity and parallax will be needed to verify its membership. If it is a member of Argus (age 30-50 Myr), then this object would have a planetary mass of 10 $\pm$ 0.5 $M_{\mathrm{Jup}}$.