Results 31 to 40 of about 5,486 (209)

Distances and ages of globular clusters using Hipparcos parallaxes of local subdwarfs [PDF]

, 1998
We discuss the impact of Population II and Globular Cluster (GCs) stars on the derivation of the age of the Universe, and on the study of the formation and early evolution of galaxies, our own in particular.
A Gould, A Renzini, A Renzini, A Sandage, A Sandage, A Sandage, A Udalsky, A Udalsky, AA Cole, AC Layden, AK Pandey, AR Walker, AU Landolt, B Chaboyer, B Chaboyer, B Madore, B Paczynski, BW Carney, BW Carney, BW Carney, BW Carney, C Cacciari, C Pryor, DA VandenBerg, DH McNamara, EL Sandquist, EP Rubestein, F Arenou, F D’Antona, F Ferraro, F Leeuwen van, F Pont, G Clementini, G Lynga, GS Costa Da, H Scheffler, HB Richer, HE Bond, I Skillen, IN Reid, IN Reid, J Fernley, J Fernley, J Fernley, J Kaluzny, J Kaluzny, J Kaluzny, J Storm, JC Wheeler, JR King, L Spitzer, M Salaris, MG Lee, MS Bessel, MW Feast, MW Feast, O Straniero, P Cote, P Fischer, PB Stetson, PM Salomon, R Zinn, RB Hanson, RG Gratton, RG Gratton, RL Kurucz, RM Rich, RP Kraft, RV Jones, S Cassisi, S Holland, SG Ryan, T Liu, T Liu, T Tsujimoto, TE Lutz, V Caloi, WB Burton, WJ Schuster   +78 more
core   +2 more sources

Primeval very low-mass stars and brown dwarfs - VI. Population properties of metal-poor degenerate brown dwarfs [PDF]

, 2019
© 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.We presented 15 new T dwarfs that were selected from UKIRT Infrared Deep Sky Survey, Visible and Infrared Survey Telescope for Astronomy, and Wide ...
Allard, F., Burgasser, A. J., Galvez-Ortiz, M. C., Lodieu, N., Osorio, M. R. Zapatero, Pinfield, D. J., Zhang, Z. H.   +6 more
core   +5 more sources

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

The magnetic fields of hot subdwarf stars [PDF]

, 2012
Detection of magnetic fields has been reported in several sdO and sdB stars. Recent literature has cast doubts on the reliability of most of these detections.
Bagnulo, Bagnulo, Borra, Elkin, J. D. Landstreet, Jordan, Kawka, L. Fossati, Mathys, O’Toole, Petit, S. Bagnulo, S. J. O’Toole, S. Jordan, Savanov, Valyavin, Østensen   +16 more
core   +1 more source

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

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   +1 more source

Distances, ages, and epoch of formation of globular clusters [PDF]

, 1999
We review the results on distances and absolute ages of galactic globular clusters (GCs) obtained after the release of the Hipparcos catalogue. Several methods for the Population II local distance scale are discussed, exploiting NEW RESULTS for RR Lyraes
Arenou F., Axer M., Bessel M. S., Buonanno R., Caldwell J. A. R., Caloi V., De Marchi G., Eugenio Carretta, Fahlman G. G., Feast M. W., Feast M. W., Fernley J., Fernley J., Ferraro F., Fischer P., Flavio Fusi Pecci, Fuhrmann K., Gisella Clementini, Gratton R. G., Gratton R. G., Hanson R. B., Laney C. D., Laney C. D., Lindgren L., Lynga G., Madau P., Oestreicher M. O., Pandey A. K., Penny A. J., Pont F., Raffaele G. Gratton, Schuster W. J., Skillen I., Storm J., Turner M. S., Udalski A., Udalski A., Van Leeuwen F., Wesselink A. J., Zhao G.   +39 more
core   +2 more sources

New ultracool subdwarfs identified in large-scale surveys using Virtual Observatory tools: II. SDSS DR7 vs UKIDSS LAS DR6, SDSS DR7 vs UKIDSS LAS DR8, SDSS DR9 vs UKIDSS LAS DR10, and SDSS DR7 vs 2MASS

, 2016
We aim at developing an efficient method to search for late-type subdwarfs (metal-depleted dwarfs with spectral types >M5) to improve the current statistics.
Aberasturi, M., Contreras, M. Espinoza, Lodieu, N., Martin, E. L., Osorio, M. R. Zapatero, Rodrigo, C., Solano, E.   +6 more
core   +1 more source

The distance to NGC 6397 by M-subdwarf main-sequence fitting [PDF]

, 1998
Recent years have seen a substantial improvement both in photometry of low luminosity stars in globular clusters and in modelling the stellar atmospheres of late-type dwarfs.
Gizis, John E., Reid, I. Neill
core   +3 more sources

Detection of stellar oscillations in HWVir

Open Astronomy, 2016
We present our analysis of K2 observations of the binary system, HWVir. We processed the raw Kepler data and used Fourier analysis to search for periodic signals that could be associated with pulsations.
Baran Andrzej S., Østensen Roy H., Telting John H.   +2 more
doaj   +1 more source