Results 21 to 30 of about 2,666,833 (318)
Rotation: a fundamental parameter of massive stars [PDF]
Symposium - International Astronomical Union, 1997 Massive stars are rapid rotators. Equatorial rotation velocities span the range vrot = 100–400 km s−1, with B stars rotating closest to their break-up speed vcrit (Howarth et al. 1997). During the last decade, many observations have revealed unusual surface abundances that may require additional internal mixing (beyond that of simple convection and ...
Langer, Norbert +2 more
openaire +2 more sources
Wide Field Multicolor CCD Photometry in the Vicinity of the Open Cluster King 7
Open Astronomy, 2010 We present the results of CCD photometry in the seven-color Vilnius system for 1549 stars down to V ∼16 mag in a 1.5 square degree field around the cluster King 7, at the Perseus and Camelopardalis border.
Zdanavičius J. +3 more
doaj +1 more source
Studying the UV Mg II Resonance Lines in 20 Be Stars
Open Astronomy, 2011 Using the GR model, we analyze the UV Mg II resonance lines in the spectra of 20 Be stars of different spectral subtypes, in order to detect the presence of satellite or discrete absorption components. The values of some physical parameters – rotational,
Antoniou A. +3 more
doaj +1 more source
Open Astronomy, 2011 White dwarf stars are traditionally found to have surface compositions made primarily of hydrogen or helium. However, a new family has recently been uncovered, the so-called hot DQ white dwarfs, which have surface compositions dominated by carbon and ...
Dufour P. +3 more
doaj +1 more source
Fundamental Parameters of Cepheids [PDF]
International Astronomical Union Colloquium, 1985 In the two centuries since the discovery of δ Cephei and η Aquilae, the study of Cepheids, and of pulsating stars in general, has become a very important field in astronomy. The usefulness of Cepheids, both as distance indicators and as test objects for stellar astrophysics, has been amply demonstrated, and if one just looks at the flood of papers on ...
openaire +1 more source
Constraining the fundamental parameters of the O-type binary CPD-41degr7733 [PDF]
, 2007 Using a set of high-resolution spectra, we studied the physical and orbital properties of the O-type binary CPD-41 7733, located in the core of \ngc.
Didelon P. +12 more
core +4 more sources
Spectral Classification of Faint Carbon Stars
Open Astronomy, 2003 R-N classification of 187 faint carbon stars is based on the classical criteria adjusted to the yellow-red spectral region, with two new criteria added - the ratios of the red CN bands 6206/6332 (Å) and 6478/6631 (Å).
Eglitis I., Eglite M., Balklavs A.
doaj +1 more source
Open Astronomy, 2003 We present a new color index vs. absolute magnitude calibration of 2MASS JHK photometry. For the A0 to ~G5 and M segments of the main sequence information on the amount of interstellar extinction and its location in space may be obtained.
Knude Jens, Fabricius Claus
doaj +1 more source
Measuring Fundamental Galactic Parameters with Stellar Tidal Streams and SIM PlanetQuest [PDF]
, 2005 Extended halo tidal streams from disrupting Milky Way satellites offer new opportunities for gauging fundamental Galactic parameters without challenging observations of the Galactic center.
Allyson A. Polak +7 more
core +1 more source
CHEMICAL COMPOSITION OF 4 STARS IN THE HYADES
Odessa Astronomical Publications, 2017 The parameters of atmospheres (Теf, 1оg g, [fе/Н], Vt) of 4 stars of Hyades are certain. Spectrums are got on a spectrograph ELODIE on a 1.93m telescope in the observatory of OHP (France). Overabundances are got 0.1 dех for all investigated elements.
E. P. Shereta
doaj +1 more source