2016A&A...596A..33R


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.16CEST17:23:02

2016A&A...596A..33R - Astronomy and Astrophysics, volume 596A, 33-33 (2016/12-1)

Spectral energy distribution of M-subdwarfs: A study of their atmospheric properties.

RAJPUROHIT A.S., REYLE C., ALLARD F., HOMEIER D., BAYO A., MOUSIS O., RAJPUROHIT S. and FERNANDEZ-TRINCADO J.G.

Abstract (from CDS):

Context. M-type subdwarfs are metal-poor low-mass stars and are probes for the old populations in our Galaxy. Accurate knowledge of their atmospheric parameters and especially their composition is essential for understanding the chemical history of our Galaxy.
Aims. The purpose of this work is to perform a detailed study of M-subdwarf spectra covering the full wavelength range from the optical to the near-infrared. It allows us to perform a more detailed analysis of the atmospheric composition in order to determine the stellar parameters, and to constrain the atmospheric models. The study will allow us to further understand physical and chemical processes such as increasing condensation of gas into dust, to point out the missing continuum opacities, and to see how the main band features are reproduced by the models. The spectral resolution and the large wavelength coverage used is a unique combination that can constrain the processes that occur in a cool atmosphere.
Methods. We obtained medium-resolution spectra (R=5000-7000) over the wavelength range 0.3-2.5µm of ten M-type subdwarfs with X-shooter at VLT. These data constitute a unique atlas of M-subdwarfs from optical to near-infrared. We performed a spectral synthesis analysis using a full grid of synthetic spectra computed from BT-Settl models and obtained consistent stellar parameters such as effective temperature, surface gravity, and metallicity.
Results. We show that state-of the-art atmospheric models correctly represent the overall shape of their spectral energy distribution, as well as atomic and molecular line profiles both in the optical and near-infrared. We find that the actual fitted gravities of almost all our sample are consistent with old objects, except for LHS 73 where it is found to be surprisingly low.

Abstract Copyright: © ESO, 2016

Journal keyword(s): stars: low-mass - subdwarfs - stars: atmospheres

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 LP 524-26 PM* 00 11 00.7862750117 +04 20 25.138497035   19.6   17.0   esdM4.5 13 0
2 L 298-71 PM* 02 42 02.8831989312 -44 30 58.743234508   13.5       sdM1 12 0
3 G 76-39 LM* 02 52 45.5138666139 +01 55 50.575567957   16.27 14.73 13.5 12.73 esdM2.0 33 0
4 L 750-42 LM* 09 43 46.1635512324 -17 47 06.289079555   14.8 13.167 12.693   sdM3.0 32 0
5 LP 857-48 LM* 14 31 38.2546329151 -25 25 32.851042214   16.8 15.68     esdM4.0 28 0
6 LP 440-52 LM* 14 39 00.3087274496 +18 39 38.704121134   19.6 18.39 17.3 14.64 sdM7.0 58 0
7 L 201-12 PM* 15 39 39.0621945051 -55 09 09.955905646   15 12.82     sdM0.5 17 0
8 L 696-92 LM* 15 43 18.3277723755 -20 15 32.908027529   14.72 13.086 12.782   M2.0VI 25 0
9 VB 12 PM* 23 17 06.0292131972 -13 50 52.312428216   19.29 16.96 16.67   esdM3 25 1
10 CD-24 17814 PM* 23 43 13.6468552201 -24 09 52.162819755   13.47 12.06 11.84   K4 29 0
11 G 275-92 PM* 23 43 16.7373061415 -24 11 16.391888956   14.23 13.7 12.38   sdK7 22 0

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2020.07.16-17:23:02

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