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Related papers: M Subdwarf Research. II. Atmospheric Parameters an…

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We present deep spectroscopy from Keck/DEIMOS of Andromeda I, III, V, VII, and X, all of which are dwarf spheroidal satellites of M31. The sample includes 256 spectroscopic members across all five dSphs. We confirm previous measurements of…

Low-mass galaxies are the building blocks of massive galaxies in the framework of hierarchical structure formation. To enable detailed studies of galactic ecosystems in dwarf galaxies by spatially resolving different galactic components, we…

We used the updated [Fe/H] abundances of 168 F-G type dwarfs and calibrated them to a third order polynomial in terms of reduced ultraviolet excess, $\delta_{0.41}$ defined with $ugr$ data in the SDSS. We estimated the $M_g$ absolute…

Astrophysics of Galaxies · Physics 2017-09-04 S. Tuncel Guctekin , S. Bilir , S. Karaali , O. Plevne , S. Ak , T. Ak , Z. F. Bostanci

M dwarfs are an important source of information when studying and probing the lower end of the Hertzsprung-Russell (HR) diagram, down to the hydrogen-burning limit. Being the most numerous and oldest stars in the galaxy, they carry…

Solar and Stellar Astrophysics · Physics 2018-02-21 A. S. Rajpurohit , F. Allard , G. D. C. Teixeira , D. Homeier , S. Rajpurohit , O. Mousis

We study dwarf galaxies in the Centaurus A group to investigate their metallicity and possible environmental effects. The Centaurus A group (at ~4 Mpc from the Milky Way) contains about 50 known dwarf companions of different morphologies…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 D. Crnojević , E. K. Grebel , A. Koch

The low metallicity interstellar medium of dwarf galaxies gives a different picture in the far infrared(FIR)/submillimetre(submm)wavelengths than the more metal-rich galaxies. Excess emission is often found in the submm beginning at or…

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 coldest metal-poor population made of T and Y dwarfs are archaeological tracers of our Galaxy because they are very old and have kept the pristine material. The optical properties of these objects are important to characterise their…

Using a spectroscopically confirmed sample of M-giants, M-dwarfs and quasars from the LAMOST survey, we assess how well WISE $\&$ 2MASS color-cuts can be used to select M-giant stars. The WISE bands are very efficient at separating M-giants…

(Abridged) We performed the spectroscopic observations of 11 confirmed GCs in M31 with the Xinglong 2.16m telescope and we mainly focus on the fits method and the metallicity gradient for the M31 GC sample. We analyzed and discussed more…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Zhou Fan , Ya-Fang Huang , Jin-Zeng Li , Xu Zhou , Jun Ma , Yong-Heng Zhao

This paper explores the gas metallicity gradients in a sample of 25 nearby galaxies using new Integral Field Spectroscopy observations from the Metal-THINGS survey. We derive and study the resolved diffuse ionised gas content, Baldwin,…

We report dynamical mass measurements for the components of the previously known double-lined spectroscopic subdwarfs G 006-026 B and C using the Fine Guidance Sensors (FGS) on the Hubble Space Telescope. To build the empirical…

Solar and Stellar Astrophysics · Physics 2016-11-15 Wei-Chun Jao , Ed Nelan , Todd Henry , Otto Franz , Lawrence Wasserman

We determine a K-band luminosity-metallicity (K-Z) relation for dwarf irregular galaxies, over a large range of magnitudes, -20.5 < M_K < -13.5, using a combination of K photometry from either the 2-micron all sky survey (2MASS) or the…

We present a volume-limited, spectroscopically-verified sample of M7$-$L5 ultracool dwarfs within 25\,pc. The sample contains 410 sources, of which $93\%$ have trigonometric distance measurements ($80\%$ from \textit{Gaia} DR2), and $81\%$…

Metal-poor M subdwarfs are among the oldest stellar populations and carry valuable information about the chemical enrichment history of the Milky Way. The measurements of chemical abundances of these stars therefore provide essential…

Solar and Stellar Astrophysics · Physics 2025-05-02 Neda Hejazi , Sebastien Lepine , Thomas Nordlander , Wei-Chun Jao , David R. Coria , Kathryn V. Lester

Comparisons between the planet populations around solar-type stars and those orbiting M dwarfs shed light on the possible dependence of planet formation and evolution on stellar mass. However, such analyses must control for other factors,…

Earth and Planetary Astrophysics · Physics 2015-06-22 Eric Gaidos , Andrew W. Mann

We investigated almost 500 stars distributed among 193 binary or multiple systems made of late-F, G-, or early-K primaries and late-K or M dwarf companion candidates. For all of them, we compiled or measured coordinates, J-band magnitudes,…

We study the metallicity distribution and kinematic properties of 4,680 A/F/G/K-type giant stars with $|z|>$ 5 kpc selected from the LAMOST spectroscopic survey. The metallicity distribution of giant stars with 5 $<|z|\leqslant$ 15 kpc can…

Astrophysics of Galaxies · Physics 2018-08-15 Shuai Liu , Cuihua Du , Heidi Jo Newberg , Yuqin Chen , Zhenyu Wu , Jun Ma , Xu Zhou , Zihuang Cao , Yonghui Hou , Yuefei Wang , Yong Zhang

The space density of late M dwarfs, subtypes M7-M9.5, is not well determined. We applied the photo-type method to $iz$ photometry from the Sloan Digital Sky Survey and $YJHK$ photometry from the UKIRT Infrared Deep Sky Survey, over an…

Solar and Stellar Astrophysics · Physics 2019-03-22 S. Ahmed , S. J. Warren