Infrared Search for Young Brown Dwarf Companions around Young Stellar Objects in the rho Ophiucus Molecular Cloud and the Serpens Molecular Cloud

Abstract

We conducted an infrared search for faint companions around 351 young stellar objects in the rho Ophiucus molecular cloud and the Serpens molecular cloud. Nine objects in the Spitzer/IRAC archival images were identified as young stellar companion candidates. They showed an intrinsic infrared excess; one object was extremely red both in the [3.6] - [4.5] color and in the [4.5] - [5.8] color, and two objects were red in the [4.5] - [5.8] color. They were as faint as 15 mag in the [3.6] band. Follow-up K-band spectroscopy revealed that three objects had deep water absorption bands, indicative of low effective temperatures. By comparing the spectra and infrared spectral energy distributions with synthesized spectra of low-temperature objects, we derived the effective temperatures and continuum excess for these objects. It seems highly likely that one of the three objects is a low-mass stellar companion and two objects are young brown dwarf companions associated with the young stellar objects.

11 pages, 7 figures. P.A.S.J. accepted

References in corpus (4)

• Accretion in the Rho-Oph pre-main sequence stars
• Emergence of Protoplanetary Disks and Successive Formation of Gaseous Planets by Gravitational Instability
• Deep Near-Infrared Imaging of the rho Oph Cloud Core: Clues to the Origin of the Lowest-Mass Brown Dwarfs
• Age Determination Method of Pre-Main Sequence Stars with High-Resolution I-Band Spectroscopy

Cited by in corpus (3)

• Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. III. Survey Overview
• Searching for planetary-mass T-dwarfs in the core of Serpens
• Keck Observations in the INfrared of Taurus and $\rho$ Oph Exoplanets And Ultracool dwarfs (KOINTREAU) II: Two Young Bound Companions to Ophiuchus Stars