J/A+A/628/A61 X-shooter spectra of 43 metal-poor M dwarfs (Lodieu+, 2019)
Metallicity, temperature, and gravity scales of M subdwarfs.
Lodieu N., Allard F., Rodrigo C., Pavlenko Y., Burgasser A., Lyubchik Y.,
Kaminsky B., Homeier D.
<Astron. Astrophys. 628, A61 (2019)>
=2019A&A...628A..61L 2019A&A...628A..61L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Spectroscopy ; Spectra, ultraviolet ;
Spectra, optical ; Spectra, infrared
Keywords: subdwarfs - stars: low-mass - techniques: spectroscopic -
infrared: stars
Abstract:
The aim of the project is to define metallicity/gravity/temperature
scales for different spectral types of metal-poor M dwarfs. We
obtained intermediate-resolution ultraviolet (UVB), optical (VIS), and
near-infrared (NIR) spectra of 43 metal-poor M dwarfs (16 sdMs, 16
esdMs, and 12 usdMs with the ESO VLT X-shooter spectrograph. We
compared our atlas of spectra to the BT-Settl synthetic spectral
energy distribution over a wide range of metallicities, gravities, and
effective temperatures to infer the physical properties for the whole
M dwarf sequence at sub-solar metallicities and constrain the latest
atmospheric models. The BT-Settl models accurately reproduce the
observed spectra across the 450--2500 nm wavelength range except for a
few regions. We find that the best fits for gravities of
log(g)=5.0-5.5 for the three metal classes. We infer metallicities of
[Fe/H]=-0.5, -1.5, and -2.0±0.5dex and effective temperatures of
3700-2600K, 3800-2900K, and 3700-2900K for sdMs, esdMs, and usdMs,
respectively.
Description:
We make public the ESO VLT X-shooter spectra of 43 subdwarfs spanning
the 560-2500nm wavelength range. Each file contains wavelength (in nm)
and the flux (in ergs/cm2/s/Angstroem) in the first and second
column, respectively. Spectra are corrected for telluric absorption.
Names of files are composed of spectral types of the source followed
by the date of observations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 93 44 Logs of the VLT/X-shooter spectroscopic
observations of M subdwarfs
sp/* . 44 VLT X-shooter VIS+NIR spectra
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 23 F4.1 arcsec DEs Declination (J2000)
25- 30 F6.3 mag i'mag Sloan i' magnitude
32- 38 A7 --- SpType Spectral type the SDSS spectroscopic database
40- 50 A11 "date" Obs.Date Date of the VLT X-shooter at the
beginning of the observation
52- 55 F4.2 --- Airm Airmass at the beginning of the observation
57- 59 I3 s ExpTU UVB arm exposure time
60 A1 --- --- [/]
61- 63 I3 s ExpTV VIS arm exposure time
64 A1 --- --- [/]
65- 67 I3 s ExpTN NIR arm exposure time
69- 71 A3 --- Cycle numbers of AB cycles (identical for all arms)
73- 93 A21 --- FileName Name of the spectrum file in subdirectory sp
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 11 F11.6 nm lambda Wavelength
13- 25 E13.7 10mW/m2/nm Flux Flux in ergs/cm2/s/Å
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Acknowledgements:
Nicolas Lodieu, nlodieu(at)iac.es
(End) Nicolas Lodieu [IAC, Tenerife, Spain], Patricia Vannier [CDS] 12-Jul-2019