2016A&A...587A..19P


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.06CEST23:47:08

2016A&A...587A..19P - Astronomy and Astrophysics, volume 587A, 19-19 (2016/3-1)

Fundamental M-dwarf parameters from high-resolution spectra using PHOENIX ACES models. I. Parameter accuracy and benchmark stars.

PASSEGGER V.M., WENDE-VON BERG S. and REINERS A.

Abstract (from CDS):

M-dwarf stars are the most numerous stars in the Universe; they span a wide range in mass and are in the focus of ongoing and planned exoplanet surveys. To investigate and understand their physical nature, detailed spectral information and accurate stellar models are needed. We use a new synthetic atmosphere model generation and compare model spectra to observations. To test the model accuracy, we compared the models to four benchmark stars with atmospheric parameters for which independent information from interferometric radius measurements is available. We used χ2-based methods to determine parameters from high-resolution spectroscopic observations. Our synthetic spectra are based on the new PHOENIX grid that uses the ACES description for the equation of state. This is a model generation expected to be especially suitable for the low-temperature atmospheres. We identified suitable spectral tracers of atmospheric parameters and determined the uncertainties in Teff, logg, and [Fe/H] resulting from degeneracies between parameters and from shortcomings of the model atmospheres. The inherent uncertainties we find are σTeff=35K, σlogg=0.14, and σ[Fe/H]=0.11. The new model spectra achieve a reliable match to our observed data; our results for Teff and logg are consistent with literature values to within 1σ. However, metallicities reported from earlier photometric and spectroscopic calibrations in some cases disagree with our results by more than 3σ. A possible explanation are systematic errors in earlier metallicity determinations that were based on insufficient descriptions of the cool atmospheres. At this point, however, we cannot definitely identify the reason for this discrepancy, but our analysis indicates that there is a large uncertainty in the accuracy of M-dwarf parameter estimates.

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Journal keyword(s): stars: low-mass - line: formation - stars: atmospheres - brown dwarfs - line: profiles - techniques: spectroscopic

Simbad objects: 7

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Number of rows : 7

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 HD 95735 Fl* 11 03 20.19400 +35 58 11.5682 10.030 8.960 7.520 5.99 4.79 M2+V 623 1
2 BD+72 545 SB* 11 45 56.1459382636 +72 05 44.606169490   10.01 8.83     K5V 29 0
3 V* V645 Cen Er* 14 29 42.9451234609 -62 40 46.170818907 14.21 12.95 11.13 9.45 7.41 M5.5Ve 958 0
4 G 224-58 LM* 15 16 49.8563071050 +60 54 37.379868154   14.33   13.18   ~ 8 0
5 HD 156384C PM* 17 18 58.8271844065 -34 59 48.612934284 12.96 11.79 10.22 10.05 8.82 M1.5V 163 1
6 NAME Barnard's star BY* 17 57 48.4997994034 +04 41 36.111354228 12.497 11.24 9.511 8.298 6.741 M4V 655 2
7 HD 173740 PM* 18 42 46.8942178098 +59 37 36.723092516   11.705   8.9   M3.5V 293 1

    Equat.    Gal    SGal    Ecl

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2020.07.06-23:47:08

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