Results 31 to 40 of about 4,354 (212)

The SALT survey of helium-rich hot subdwarfs: methods, classification, and coarse analysis [PDF]

Monthly notices of the Royal Astronomical Society, 2020
A medium- and high-resolution spectroscopic survey of helium-rich hot subdwarfs is being carried out using the Southern African Large Telescope (SALT).
Simon Jeffery, B. Miszalski, E. Snowdon
semanticscholar   +1 more source

Mode identification in three pulsating hot subdwarfs observed with TESS satellite [PDF]

Monthly notices of the Royal Astronomical Society, 2020
We report on the detection of pulsations of three pulsating subdwarf B stars observed by the Transiting Exoplanet Survey Satellite (TESS) satellite and our results of mode identification in these stars based on an asymptotic period relation.
S. K. Sahoo, A. Baran, U. Heber, J. Ostrowski, S. Sanjayan, R. Silvotti, A. Irrgang, M. Uzundag, M. Reed, K. A. Shoaf, R. Raddi, M. Vučković, H. Ghasemi, W. Zong, K. J. B. A. R. Group, I. O. Physics, P. U. -. Krakow, Poland., Nicolaus Copernicus Astronomical Center of the Polish Acade Sciences, Remeis-Sternwarte, Ecap, A. Institute, University of Erlangen-Nurnberg, Germany, I. Torino, Italy, I. D. Astronomía, F. Ciencias, Univ. de Valparaiso, Chile., E. Observatory, D. Physics, Astronomy, M. Science, Missouri State University, Usa, U. P. D. Catalunya, Spain., Institute for Research in Fundamental Sciences, Iran, D. O. Astronomy, Beijing Normal University, P. China, D. Institute, U. Washington, Nsf Astronomy, A. Fellow   +46 more
semanticscholar   +1 more source

Spectral models for binary products: Unifying subdwarfs and Wolf-Rayet stars as a sequence of stripped-envelope stars [PDF]

Astronomy & Astrophysics, 2018
Stars stripped of their hydrogen-rich envelope through interaction with a binary companion are generally not considered when accounting for ionizing radiation from stellar populations, despite the expectation that stripped stars emit hard ionizing ...
Y. Götberg, S. D. Mink, J. Groh, T. Kupfer, P. Crowther, E. Zapartas, M. Renzo   +6 more
semanticscholar   +1 more source

Opacity modelling of heavy-metal hot subdwarfs: photoionization of Sr0, Y+, and Zr2 + [PDF]

, 2020
Heavy-metal hot subdwarfs (sdB and sdO) represent a small group of stars with unusually high concentrations of trans-iron elements in their atmospheres, having abundances ~ 10000 times solar. One example is LS IV-14$^{\circ}$ 116, where a number of heavy-
L. Fern'andez-Menchero, C. Jeffery, C. Ramsbottom, C. Ballance   +3 more
semanticscholar   +1 more source

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, J. Kirkpatrick, S. Fajardo-Acosta, M. Penny, B. Gaudi, M. Veyette, P. Boeshaar, C. Henderson, M. Cushing, S. Calchi-Novati, Y. Shvartzvald, P. Muirhead   +11 more
semanticscholar   +1 more source

The quest for planets around subdwarfs and white dwarfs from Kepler space telescope fields [PDF]

Astronomy & Astrophysics, 2020
Context. In this study, we independently test the presence of an exoplanet around the binary KIC 9472174, which is composed of a red dwarf and a pulsating type B subdwarf.
J. Krzesinski, A. Blokesz, M. Siwak, G. Stachowski   +3 more
semanticscholar   +1 more source

In Pursuit of the Least Luminous Galaxies

Advances in Astronomy, Volume 2010, Issue 1, 2010., 2010
The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10−7LMW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the distribution, mass spectrum, and clustering scale of dark matter.
Beth Willman, Regina Schulte-Ladbeck
wiley   +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, Z. Zhang, Z. Zhang, M. Gálvez-Ortiz, D. Pinfield, A. Burgasser, N. Lodieu, N. Lodieu, H. Jones, E. Martín, B. Burningham, D. Homeier, F. Allard, M. R. Z. Osorio, L. Smith, L. Smith, R. L. Smart, B. L. Marti, F. Marocco, F. Marocco, R. Rebolo, R. Rebolo   +21 more
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., Fuchs, B., Jahreiss, H., Wielen, R.   +3 more
openaire   +2 more sources

Chemical Properties of the Local Galactic Disk and Halo. I. Fundamental Properties of 1544 Nearby, High Proper-motion M Dwarfs and Subdwarfs [PDF]

Astronomical Journal, 2019
Due to their ubiquity and very long main-sequence lifetimes, M dwarfs provide an excellent tool to study the formation and chemical enrichment history of our Galaxy.
N. Hejazi, S. Lépine, D. Homeier, R. Michael Rich, M. Shara   +4 more
semanticscholar   +1 more source