Results 1 to 10 of about 7,790 (232)

Asteroseismic Observations of Hot Subdwarfs [PDF]

Frontiers in Astronomy and Space Sciences, 2021
There are a number of reasons for studying hot subdwarf pulsation; the most obvious being that these stars remain a poorly understood late-stage of stellar evolution and knowledge of their interior structure, which pulsation studies reveal, constrains ...
A. E. Lynas-Gray, A. E. Lynas-Gray, A. E. Lynas-Gray   +2 more
doaj   +3 more sources

New Cold Subdwarf Discoveries from Backyard Worlds and a Metallicity Classification System for T Subdwarfs

The Astrophysical Journal
We report the results of a spectroscopic survey of candidate T subdwarfs identified by the Backyard Worlds: Planet 9 program. Near-infrared spectra of 31 sources with red J  − W2 colors and large J -band reduced proper motions show varying signatures of ...
Adam J. Burgasser, Adam C. Schneider, Aaron M. Meisner, Dan Caselden, Chih-Chun Hsu, Roman Gerasimov, Christian Aganze, Emma Softich, Preethi Karpoor, Christopher A. Theissen, Hunter Brooks, Thomas P. Bickle, Jonathan Gagné, Ètienne Artigau, Michaël Marsset, Austin Rothermich, Jacqueline K. Faherty, J. Davy Kirkpatrick, Marc J. Kuchner, Nikolaj Stevnbak Andersen, Paul Beaulieu, Guillaume Colin, Jean Marc Gantier, Leopold Gramaize, Les Hamlet, Ken Hinckley, Martin Kabatnik, Frank Kiwy, David W. Martin, Diego H. Massat, William Pendrill, Arttu Sainio, Jörg Schümann, Melina Thévenot, Jim Walla, Zbigniew Wędracki, The Backyard Worlds: Planet 9 Collaboration   +36 more
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Hot Subdwarf Stars [PDF]

Annual Review of Astronomy and Astrophysics, 2009
Hot subdwarf stars (sdBs, sdOs) are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. They are found in all Galactic stellar populations and are sufficiently common to account for the UV-upturn of early-type galaxies.
U. Heber
openalex   +3 more sources

X-rays from Hot Subdwarfs [PDF]

Advances in Space Research, 2015
Thanks to the high sensitivity of the instruments on board the XMM-Newton and Chandra satellites, it has become possible to explore the properties of the X-ray emission from hot subdwarfs.
La Palombara, Nicola, Mereghetti, Sandro
core   +6 more sources

The masses of hot subdwarfs [PDF]

, 2009
Masses are a fundamental parameter, but they are not well known for most hot subdwarfs. In general, the mass of a hot subdwarf is derived with asteroseismology or dynamical methods, for which it is often difficult to obtain the necessary data from ...
Alexander, Brassard, Charpinet, Charpinet, Charpinet, Chen, D'Cruz, Dorman, Eggleton, Eggleton, Eggleton, Fontaine, Han, Han, Han, Han, Heber, Heber, Heber, Iben, Iglesias, Kilkenny, Kilkenny, Lisker, Maxted, Maxted, Mengel, Meohler, Napiwotzki, O'Toole, Pols, Pols, Saffer, Schröder, Stroeer, Webbink, Wood, X. Chen, X. Zhang, Z. Han, Østensen   +40 more
core   +3 more sources

Hot Subdwarfs in Resolved Binaries [PDF]

Astrophysics and Space Science, 2010
In the last decade or so, there have been numerous searches for hot subdwarfs in close binaries. There has been little to no attention paid to wide binaries however. The advantages of understanding these systems can be many.
A. Ströer, H. Drechsel, H. Harris, H. Saio, I.N. Reid, Ivezic, K. Cruz, M. Castellani, M. Vuckovic, R. Napiwotzki, R. Silvotti, R. Østensen, S. Charpinet, S. Hawley, S.J. O’Toole, Simon J. O’Toole, T. Lanz, T. Lisker, U. Heber, U. Heber, V.M. Woolf, Z. Han   +21 more
core   +2 more sources

A spectroscopic and proper motion search of Sloan Digital Sky Survey : red subdwarfs in binary systems [PDF]

, 2013
Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with Sloan Digital Sky Survey spectroscopy.
A. C. Day-Jones, Abazajian, Adelman-McCarthy, Aihara, Allard, Andrei, B. Burningham, B. Sipőcz, Baade, Baraffe, Baraffe, Bessell, Bessell, Bowler, Brott, Burgasser, Burgasser, Burgasser, Burgasser, Burgasser, Burgasser, Burgasser, Burgasser, Burningham, Burningham, Burningham, Burrows, Catalán, Chabrier, Costa, Costa, Cushing, D. J. Pinfield, D. N. Murray, Dahn, Dahn, Dahn, Day-Jones, Dearborn, Dhital, Dominguez, Downes, Dupuy, Dupuy, Duquennoy, F. Marocco, Faherty, Faherty, Faherty, Fischer, Garcés, Gass, Gatewood, Gilmore, Gizis, Gizis, Gliese, H. R. A. Jones, Han, Harrington, Helling, Henry, J. Gomes, J. R. A. Clarke, Jao, Jao, Jao, Jao, Jao, Jenkins, Kaltenegger, Kirkpatrick, Kirkpatrick, Kirkpatrick, Kuiper, Lawrence, Leggett, Lodieu, Lodieu, Lodieu, Lowrance, Luhman, Lépine, Lépine, Lépine, Lépine, Lépine, Lépine, Lépine, M. C. Gálvez-Ortiz, M. K. Kuznetsov, Margon, Marley, Marshall, Montalbán, Monteiro, Munn, Murray, Napiwotzki, Neves, Pauli, Perryman, Pinfield, Plez, Prugniel, R. L. Smart, Reid, Riaz, Riedel, Rojas-Ayala, Rojas-Ayala, Roman, Roman, Roman, S. Catalán, S. Lépine, Salaris, Saumon, Schilbach, Schmidt, Scholz, Scholz, Schweitzer, Sivarani, Smart, Spagna, Steinhardt, Terrien, Tremblay, Udry, van Altena, van Dokkum, van Leeuwen, Vrba, Witte, Woolf, Ya. V. Pavlenko, York, Z. H. Zhang, Zhang, Zhang, Zhang, Önehag   +142 more
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Revised Metallicity Classes for Low‐Mass Stars: Dwarfs (dM), Subdwarfs (sdM), Extreme Subdwarfs (esdM), and Ultrasubdwarfs (usdM) [PDF]

The Astrophysical Journal, 2007
The current classification system of M stars on the main sequence distinguishes three metallicity classes (dwarfs - dM, subdwarfs - sdM, and extreme subdwarfs - esdM). The spectroscopic definition of these classes is based on the relative strength of prominent CaH and TiO molecular absorption bands near 7000A, as quantified by three spectroscopic ...
Sébastien Lépine, R. Michael Rich, Michael M. Shara   +2 more
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X-ray emission from hot subdwarfs with compact companions

EPJ Web of Conferences, 2013
We review the X-ray observations of hot subdwarf stars. While no X-ray emission has been detected yet from binaries containing B-type subdwarfs, interesting results have been obtained in the case of the two luminous O-type subdwarfs HD 49798 and BD + 37° 
Esposito P., La Palombara N., Mereghetti S., Tiengo A.   +3 more
doaj   +2 more sources

Hot subdwarf stars in close-up view - III. Metal abundances of subdwarf B stars [PDF]

Astronomy & Astrophysics, 2012
Context: Hot subdwarf B stars (sdBs) are considered to be core helium-burning stars with very thin hydrogen envelopes situated on or near the extreme horizontal branch (EHB). The formation of sdBs is still unclear as well as the chemical composition of their atmospheres. The observed helium depletion is attributed to atmospheric diffusion.
S. Geier
openalex   +4 more sources