A Methane Imaging Survey for T Dwarf Candidates in Rho Ophiuchi

TL;DR

This study conducted a deep near-infrared methane imaging survey of the Rho Ophiuchi cloud core, identifying 22 T dwarf candidates with masses comparable to planets, potentially the youngest and lowest mass free-floating objects with circumstellar disks.

Contribution

First wide-field methane imaging survey of Rho Ophiuchi identifying planetary-mass T dwarf candidates and their potential disks, extending the initial mass function into planetary regimes.

Findings

22 T dwarf candidates identified among 6587 objects

Candidates have masses between 1 and 2 Jupiter masses

59% of candidates may have circumstellar disks

Abstract

We report the results of the first deep, wide-field, near-infrared methane imaging survey of the Rho Ophiuchi cloud core to search for T dwarfs. Among the 6587 objects detected, 22 were identified as T dwarf candidates. Brown dwarf models indicate that at the age and distance of the Rho Ophiuchi cloud, these T dwarf candidates have masses between 1 and 2 Jupiter masses. If confirmed as genuine T dwarfs, these objects would be the youngest, lowest mass, and lowest gravity free-floating objects ever directly observed. The existence of these candidates suggests that the initial mass function of the Rho Ophiuchi cloud extends well into the regime of planetary mass objects. A large fraction (59% +/- 16%) of our T dwarf candidates appear to be surrounded by circumstellar disks, and thus represent the lowest mass objects yet found to harbor circumstellar disks.