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Knowledge of stellar atmospheric parameters ($T_{\rm eff}$, $\log{g}$, [Fe/H]) of M dwarfs can be used to constrain both theoretical stellar models and Galactic chemical evolutionary models, and guide exoplanet searches, but their…

Solar and Stellar Astrophysics · Physics 2023-02-22 C. Duque-Arribas , D. Montes , H. M. Tabernero , J. A. Caballero , J. Gorgas , E. Marfil

Based on a carefully constructed sample of dwarf stars, a new optical-near infrared photometric calibration to estimate the metallicity of late-type K and early-to-mid-type M dwarfs is presented. The calibration sample has two parts; the…

Solar and Stellar Astrophysics · Physics 2015-06-24 Neda Hejazi , Michael M. De Robertis , Peter C. Dawson

Metallicity is a fundamental parameter that contributes to the physical characteristics of a star. However, the low temperatures and complex molecules present in M dwarf atmospheres make it difficult to measure their metallicities using…

The MEarth Project is a photometric survey systematically searching the smallest stars nearest to the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late…

Solar and Stellar Astrophysics · Physics 2016-03-09 Jason A Dittmann , Jonathan M Irwin , David Charbonneau , Elisabeth R Newton

Context. Several new techniques to determine the metallicity of M dwarfs with better precision have been developed over the last decades. However, most of these studies were based on empirical methods. In order to enable detailed abundance…

Solar and Stellar Astrophysics · Physics 2016-02-03 Sara Lindgren , Ulrike Heiter , Andreas Seifahrt

Context. Reliable metallicity values for M dwarfs are important for studies of the chemical evolution and advancement of planet formation theory in low-mass environments. Historically the determination of stellar parameters of low-mass…

Solar and Stellar Astrophysics · Physics 2017-08-16 Sara Lindgren , Ulrike Heiter

Deriving metallicities for solar-like stars follows well-established methods, but for cooler stars such as M dwarfs, the determination is much more complicated due to forests of molecular lines that are present. Several methods have been…

The relativley large spread in the derived metallicities ([Fe/H]) of M dwarfs shows that various approaches have not yet converged to consistency. The presence of strong molecular features, and incomplete line lists for the corresponding…

Solar and Stellar Astrophysics · Physics 2015-06-03 Anna Önehag , Ulrike Heiter , Bengt Gustafsson , Nikolai Piskunov , Bertrand Plez , Ansgar Reiners

M dwarfs are the most abundant stars in the Solar Neighborhood and they are prime targets for searching for rocky planets in habitable zones. Consequently, a detailed characterization of these stars is in demand. The spectral sub-type is…

Instrumentation and Methods for Astrophysics · Physics 2023-04-28 Sirinrat Sithajan , Sukanya Meethong

We obtained high resolution ELODIE and CORALIE spectra for both components of 20 wide visual binaries composed of an F-, G- or K-dwarf primary and an M-dwarf secondary. We analyse the well understood spectra of the primaries to determine…

Astrophysics · Physics 2007-05-23 X. Bonfils , X. Delfosse , S. Udry , N. C. Santos , T. Forveille , D. Ségransan

Knowledge of the metallicities of M dwarfs rests predominantly on the photometric calibration of Bonfils and collaborators, which predicts that M dwarfs in the solar neighborhood, including those with known planets, are systematically…

Earth and Planetary Astrophysics · Physics 2011-02-11 John A. Johnson , Kevin Apps

Despite the advances provided by large-scale photometric surveys, stellar features - such as metallicity - generally remain limited to spectroscopic observations often of bright, nearby low-extinction stars. To rectify this, we present a…

Astrophysics of Galaxies · Physics 2022-10-19 Connor P. Fallows , Jason L. Sanders

The location of M dwarfs in the V-K_s--M_Ks color-magnitude diagram (CMD) has been shown to correlate with metallicity. We demonstrate that previous empirical photometric calibrations of M dwarf metallicity exploiting this correlation…

Earth and Planetary Astrophysics · Physics 2015-05-19 Kevin C. Schlaufman , Gregory Laughlin

Stellar parameters are not easily derived from M dwarf spectra, which are dominated by complex bands of diatomic and triatomic molecules and not well described at the line by line level by atmospheric models. M dwarf metallicities are…

Solar and Stellar Astrophysics · Physics 2015-05-30 V. Neves , X. Bonfils , N. C. Santos , X. Delfosse , T. Forveille , F. Allard , C. Natário , C. S. Fernandes , S. Udry

Knowledge of late K and M dwarf metallicities can be used to guide planet searches and constrain planet formation models. However, the determination of metallicities of late-type stars is difficult because visible wavelength spectra of…

Solar and Stellar Astrophysics · Physics 2014-05-16 Andrew W. Mann , John M. Brewer , Eric Gaidos , Sebastien Lepine , Eric J. Hilton

We present evidence that there is an M dwarf problem similar to the previously identified G dwarf and K dwarf problems: the number of low-metallicity M dwarfs is not sufficient to match simple closed-box models of local Galactic chemical…

Solar and Stellar Astrophysics · Physics 2015-06-04 Vincent M. Woolf , Andrew A. West

Identification of metal-poor stars among field stars is extremely useful for studying the structure and evolution of the Galaxy and of external galaxies. We search for metal-poor stars using the artificial neural network (ANN) and extend…

Solar and Stellar Astrophysics · Physics 2015-06-16 Sunetra Giridhar , Aruna Goswami , Andrea Kunder , S. Muneer , G. Selvakumar

We describe a method for accurately determining M dwarf metallicities with spectral synthesis based on abundance analyses of visual binary stars. We obtained high resolution, high signal-to-noise spectra of each component of five visual…

Aims. In this work we develop a technique to obtain high precision determinations of both metallicity and effective temperature of M dwarfs in the optical. Methods. A new method is presented that makes use of the information of 4104 lines…

Solar and Stellar Astrophysics · Physics 2014-09-05 V. Neves , X. Bonfils , N. C. Santos , X. Delfosse , T. Forveille , F. Allard , S. Udry

A growing number of indicators are now being used with some confidence to measure the metallicity(Z) of photoionisation regions in planetary nebulae, galactic HII regions(GHIIRs), extra-galactic HII regions(EGHIIRs) and HII galaxies(HIIGs).…

Astrophysics · Physics 2012-05-10 Michael Taylor , Angeles I. Diaz
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