Results 21 to 30 of about 276,909 (151)
Radii of 88 M Subdwarfs and Updated Radius Relations for Low-metallicity M-dwarf Stars [PDF]
Astronomical Journal, 2018 M subdwarfs are low-metallicity M dwarfs that typically inhabit the halo population of the Galaxy. Metallicity controls the opacity of stellar atmospheres; in metal-poor stars, hydrostatic equilibrium is reached at a smaller radius, leading to smaller ...
Aurora Y. Kesseli +11 more
semanticscholar +1 more source
A search for heavy-metal stars: abundance analyses of hot subdwarfs with Subaru★ [PDF]
Monthly notices of the Royal Astronomical Society, 2019 The discovery of extremely zirconium- and lead-rich surfaces amongst a small subgroup of hot subdwarfs has provoked questions pertaining to chemical peculiarity in hot star atmospheres and about their evolutionary origin. With only three known in 2014,
N. N., C. Jeffery, V. Woolf
semanticscholar +1 more source
Kinematics of nearby subdwarf stars [PDF]
Astronomy & Astrophysics, 2005 We present an analysis of the space motions of 742 subdwarf stars based on the sample of Carney et al. (1994, CLLA). Hipparcos parallaxes, TYC2+HIP proper motions and Tycho2 proper motions were combined with radial velocities and metallicities from CLLA. The kinematical behavior is discussed in particular in relation to their metallicities.
Arifyanto, M. I. +3 more
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Searching for hot subdwarf stars from the LAMOST Spectra. II. Pure spectroscopic identification method for hot subdwarfs [PDF]
Nippon Tenmon Gakkai obun kenkyu hokoku, 2019 Employing a new machine learning method, named hierarchical extreme learning machine (HELM) algorithm, we identified 56 hot subdwarf stars in the first data release (DR1) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) survey ...
Z. Lei +4 more
semanticscholar +1 more source
Primeval very low-mass stars and brown dwarfs – IV. New L subdwarfs, Gaia astrometry, population properties, and a blue brown dwarf binary [PDF]
Monthly notices of the Royal Astronomical Society, 2018 We present 27 new L subdwarfs and classify five of them as esdL and 22 as sdL. Our L subdwarf candidates were selected with the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Spectroscopic follow-up was carried out primarily with the OSIRIS
Z. Zhang +21 more
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A search for transiting planets around hot subdwarfs [PDF]
Astronomy & Astrophysics, 2021 Context. Hot subdwarfs experienced strong mass loss on the red giant branch (RGB) and are now hot and small He-burning objects. These stars constitute excellent opportunities for addressing the question of the evolution of exoplanetary systems directly ...
V. Van Grootel +81 more
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The Formation of Subdwarf B Stars [PDF]
International Astronomical Union Colloquium, 2002 AbstractWe performed full binary evolution calculations and carried out binary population synthesis studies in order to investigate the formation of subdwarf B (sdB) stars via the channels of stable Roche lobe overflow (RLOF), common envelope ejection and helium white dwarf mergers. Our model is successful in the explanation of observational properties
Han, Z +4 more
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Radial velocity variability and the evolution of hot subdwarf stars [PDF]
Astronomy & Astrophysics, 2022 Hot subdwarf stars represent a late and peculiar stage in the evolution of low-mass stars, since they are likely formed by close binary interactions. In this work, we perform a radial velocity (RV) variability study of a sample of 646 hot subdwarfs with ...
S. Geier +5 more
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A transit survey to search for planets around hot subdwarfs
Bulletin de la Société royale des sciences de Liège, 2023 Hot subdwarf stars are small post-red-giant-branch stars. To this day, no planets have been confirmed around them. In this document we present the first results of our analysis to quantify the presence of planets around hot subdwarfs by performing a wide
A. Thuillier +5 more
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A Grid of Synthetic Spectra for Subdwarfs: Non-LTE Line-blanketed Atmosphere Models [PDF]
Astrophysical Journal Supplement Series, 2021 A new grid of detailed atmosphere model spectra for hot and moderately cool subdwarf stars is presented. High-resolution spectra and synthetic photometry are calculated in the range from 1000–10,000 Å using non-LTE fully line-blanketed atmosphere ...
T. A. Pacheco +3 more
semanticscholar +1 more source