J/A+A/581/A73 Luhman 16AB X-shooter spectra (Lodieu+, 2015)
VLT X-shooter spectroscopy of the nearest brown dwarf binary.
Lodieu N., Zapatero Osorio M.R., Rebolo R., Bejar V.J.S., Pavlenko Y.,
Perez-Garrido A.
<Astron. Astrophys. 581, A73 (2015)>
=2015A&A...581A..73L 2015A&A...581A..73L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, late-type ; Spectroscopy
Keywords: techniques: spectroscopic - stars: brown dwarfs - binaries: general -
stars: fundamental parameters
Abstract:
We obtained high signal-to-noise intermediate-resolution
(R∼6000-11000) optical (600-1000nm) and near-infrared (1000-2480nm)
spectra of each component of the the closest brown dwarf binary,
Luhman 16AB, with X-Shooter on the Very Large Telescope (VLT). We
classify the primary and secondary as L6-L7.5 and T0±1,
respectively, in agreement with previous measurements. We present
measurements of the lithium pseudo-equivalent widths, which appears of
similar strength on both components. The presence of lithium (7Li)
in both components imply masses below 0.06M_☉ while comparison
with models suggests lower limits of 0.04M_☉. The detection of
lithium in the T component is the first of its kind. Similarly, we
assess the strength of other alkali lines (e.g. 6-7Å for RbI and
4-7Å for CsI features) and compare them with estimates for L and T
dwarfs. We also derive effective temperatures and luminosities of each
component of the binary (-4.66dex, 1305K) and (-4.68dex, 1320K) for
the L and T dwarf, respectively. Using our radial velocity
determinations, the binary does not appear to belong to any of the
well-known moving group. Our preliminary theoretical analysis of the
optical and J-band spectra indicates that the L- and T-type spectra
can be reproduced with a single temperature and gravity but different
relative chemical abundances which impact strongly the spectral energy
distribution of L/T transition objects.
Description:
VLT X-shooter optical and near-infrared spectra of each component of
the nearest brown dwarf binary system Luhman 16AB are made public. The
spectra cover the ∼670nm to ∼2480nm with a resolution of 11000 in the
optical (670-1000nm) and 6200 in the near-infrared (1000-2480nm).
Note: We observe a peak and a dip around 2080-2090nm in the spectra
of the components of the system not seen in other T dwarfs, as a
potential artefact in our X-shooter data. No other strong artefact is
present in our data.
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
10 49 15.58 -53 19 06.1 Luhman 16AB = ** LUH 16
----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
spluh16a.dat 21 136203 VLT/X-shooter spectrum of Luhman16A
spluh16b.dat 21 136045 VLT/X-shooter spectrum of Luhman16B
--------------------------------------------------------------------------------
Byte-by-byte Description of file: spluh16a.dat spluh16b.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.4 nm Lambda Wavelength in nm
11- 21 F11.8 10mW/m2/nm Flux Flux in ergs/cm2/s/Å
--------------------------------------------------------------------------------
Acknowledgements:
Nicolas Lodieu, nlodieu(at)iac.es
(End) Nicolas Lodieu (IAC, Tenerife, Spain), Patricia Vannier [CDS] 06-Jul-2015