Two class I very low-mass objects in Taurus

TL;DR

This study confirms two proto-brown dwarf candidates in Taurus are at the class I stage and estimates their final masses, supporting the idea that brown dwarfs form through similar processes as low-mass stars.

Contribution

First direct confirmation of class I stage in very low-mass objects, with mass estimates supporting common formation pathways with low-mass stars.

Findings

Confirmed class I evolutionary stage of two proto-brown dwarf candidates.

Estimated upper mass limits indicating they will become brown dwarfs or very low-mass stars.

Supports the scenario that brown dwarfs share formation stages with low-mass stars.

Abstract

We report our study of two proto-brown dwarf candidates in Taurus, [GKH94]~41 and IRAS~04191+1523B. Based on continuum maps at 102~GHz (or 2.9~mm), spectral types and the spectral energy distribution of both targets, we confirmed the class I evolutionary stage of [GKH94]~41 and IRAS~04191+1523B, and estimated the upper limit to the final masses to be 49$^{+56}_{-27}$~$M_{\rm J}$ and 75$^{+40}_{-26}$~$M_{\rm J}$ for [GKH94]~41 and IRAS~04191+1523B, respectively. This indicates that they will likely end up as brown dwarfs or very low-mass stars. The existence of these class I very low-mass objects strongly supports the scenario that brown dwarfs and very low-mass stars have the same formation stages as low-mass stars.