Results 1 to 10 of about 1,023 (124)

Purple dwarfs: New L subdwarfs from UKIDSS and SDSS [PDF]

EPJ Web of Conferences, 2013
The first L subdwarf was a discovered only ten years ago. Less than ten L subdwarfs been published in the literature to date. Metal-poor ultracool atmospheres has not been well understood.
Marocco F., Day-Jones A.C., Jones H.R.A., Burningham B., Pinfield D.J., Zhang Z.H., Gomes J., Galvez-Ortiz M.C.   +7 more
doaj   +2 more sources

Subaru and Salt Spectroscopy of Chemically Peculiar Hot Subdwarfs [PDF]

Open Astronomy, 2017
The majority of hot subdwarfs lie on or close to the helium main-sequence. Many have hydrogen-rich surfaces, but a substantial fraction of the hotter subdwarfs have hydrogen-depleted or hydrogen-deficient surfaces. Amongst the former, three were known to
Jeffery C. Simon, Neelamkodan Naslim, Woolf Vincent M., Crawford Steven M., Østensen Roy H.   +4 more
doaj   +4 more sources

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

HST spectroscopy of chemically peculiar hot subdwarfs: PG 0909+276 and UVO0512–08 [PDF]

Open Astronomy, 2017
High-resolution ultraviolet spectroscopy of two chemically peculiar hot subdwarfs, PG 0909+276 and UVO0512-08, has been obtained using the Hubble Space Telescope.
Wild James, Jeffery Christopher Simon
doaj   +2 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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Asteroseismic Observations of Hot Subdwarfs

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   +1 more source

A FEROS Survey of Hot Subdwarf Stars

Open Astronomy, 2018
We have completed a survey of twenty-two ultraviolet-selected hot subdwarfs using the Fiber-fed Extended Range Optical Spectrograph (FEROS) and the 2.2-m telescope at La Silla. The sample includes apparently single objects as well as hot subdwarfs paired
Vennes Stéphane, Németh Péter, Kawka Adela   +2 more
doaj   +1 more source

New observations and asteroseismic analysis of the subdwarf B pulsator PG 1219+534

Open Astronomy, 2018
We present a new asteroseismic modeling of the hot B subdwarf (sdB) pulsator PG 1219+534, based on a 3- month campaign with the Mont4K/Kuiper combination at Mt Bigelow (Arizona) and on updated atmospheric parameters from high S/N low and medium ...
Van Grootel Valérie, Péters Marie-Julie, Green Elizabeth M., Charpinet Stéphane, Brassard Pierre, Fontaine Gilles   +5 more
doaj   +1 more source

Spectroscopic and Photometric Analysis of the HW Vir Star PTF1 J011339.09+225739.1

Open Astronomy, 2018
HW Vir systems are rare eclipsing binary systems including a subdwarf B star (sdB) with a faint companion, mostly M-dwarfs. Up to now, 19 HW Vir systems have been published, three of them with substellar companions. We report the spectroscopic as well as
Wolz Maximilian, Kupfer Thomas, Drechsel Horst, Heber Ulrich, Irrgang Andreas, Hermes J.J., Bloemen Steven, Levitan David, Dhillon Vik, Marsh TomR.   +9 more
doaj   +1 more source

A 500 pc volume-limited sample of hot subluminous stars

Astronomy & Astrophysics
We present a quantitative spectroscopic and kinematic analysis of a volume-complete sample of hot subluminous stars within 500 pc of the Sun, assembled using accurate parallax measurements from the Gaia space mission Data Release 3 (DR3).
Dawson H., Dorsch M., Geier S., Munday J., Pritzkuleit M., Heber U., Mattig F., Benitez-Palacios D., Vučković M., Pelisoli I., Deshmukh K., Bhat A., Kufleitner L., Uzundag M., Schaffenroth V., Reindl N., Culpan R., Raddi R., Antunes Amaral L., Istrate A. G., Justham S., Østensen R. H., Telting J. H., Steinmetz T., Rodríguez-Segovia N., Fernandez-Schlosser P., Durán-Reyes A., Arancibia-Rojas E., Latour M., Jones G. T., O’Brien M., Sahu S., Elms A.   +32 more
doaj   +3 more sources