Accretion signatures in the X-shooter spectrum of the substellar companion to SR12

Alejandro Santamaría-Miranda, Claudio Cáceres, Matthias R. Schreiber, Adam Hardy, Amelia Bayo, Steven G. Parsons, Mariusz Gromadzki, Aurora Belén Aguayo Villegas

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

About a dozen substellar companions orbiting young stellar objects or pre-main sequence stars at several hundred au have been identified in the last decade. These objects are interesting both due to the uncertainties surrounding their formation, and because their large separation from the host star offers the potential to study the atmospheres of young giant planets and brown dwarfs. Here, we present X-shooter spectroscopy of SR 12 C, a ~2Myr young brown dwarf orbiting SR 12 at an orbital separation of 1083 au. We determine the spectral type, gravity, and effective temperature via comparison with models and observational templates of young brown dwarfs. In addition, we detect and characterize accretion using several accretion tracers. We find SR 12C to be a brown dwarf of spectral type L0 ± 1, log g = 4 ± 0.5, an effective temperature of 2600 ± 100 K. Our spectra provide clear evidence for accretion at a rate of ~10-10M yr-1. This makes SR 12 one of the few sub-stellar companions with a reliable estimate for its accretion rate. A comparison of the ages and accretion rates of sub-stellar companions with young isolated brown dwarfs does not reveal any significant differences. If further accretion rate measurements of a large number of substellar companions can confirm this trend, this would hint towards a similar formation mechanism for substellar companions at large separations and isolated brown dwarfs.

Original languageEnglish
Pages (from-to)2994-3003
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume475
Issue number3
DOIs
Publication statusPublished - 1 Apr 2018

Keywords

  • Accretion
  • Accretion discs
  • Brown dwarfs
  • Stars: pre-main-sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'Accretion signatures in the X-shooter spectrum of the substellar companion to SR12'. Together they form a unique fingerprint.

Cite this