Bibcode
Riaz, B.; Thompson, M.; Whelan, E. T.; Lodieu, N.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 446, Issue 3, p.2550-2559
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1
2015
Citations
19
Refereed citations
18
Description
We present an optical to submillimetre multiwavelength study of two very
low-luminosity Class I/flat systems, Mayrit 1701117 and Mayrit 1082188,
in the σ Orionis cluster. We performed moderate-resolution (R
˜ 1000) optical (˜0.4-0.9 μm) spectroscopy with the
Cassegrain Twin Spectrograph (TWIN) spectrograph at the Calar Alto 3.5-m
telescope. The spectra for both sources show prominent emission in
accretion- and outflow-associated lines. The mean accretion rate
measured from multiple line diagnostics is 6.4 × 10-10
M⊙ yr-1 for Mayrit 1701117 and 2.5 ×
10-10 M⊙ yr-1 for Mayrit 1082188.
The outflow mass-loss rates for the two systems are similar and
estimated to be ˜1 × 10-9 M⊙
yr-1. The activity rates are within the range observed for
low-mass Class I protostars. We obtained submillimetre continuum
observations with the Submillimetre Common-User Bolometer Array
(SCUBA-2) bolometer at the James Clerk Maxwell Telescope. Both objects
are detected at a ≥5σ level in the SCUBA-2 850-μm band. The
bolometric luminosity of the targets as measured from the observed
spectral energy distribution over ˜0.8-850 μm is 0.18 ±
0.04 L⊙ for Mayrit 1701117 and 0.16 ± 0.03
L⊙ for Mayrit 1082188 and is in the very low mass range.
The total dust+gas mass derived from submillimetre fluxes is ˜36
MJup and ˜22 MJup for Mayrit 1701117 and
Mayrit 1082188, respectively. There is the possibility that some of the
envelope material might be dissipated by the strong outflows driven by
these sources, resulting in a final mass of the system close to or below
the substellar limit.
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