Results 11 to 20 of about 512,862 (249)

The impact of a fossil magnetic field on dipolar mixed-mode frequencies in sub- and red-giant stars [PDF]

, 2020
Stars more massive than $\sim 1.3$ M$_\odot$ are known to develop a convective core during the main-sequence: the dynamo process triggered by this convection could be the origin of a strong magnetic field inside the core of the star, trapped when it becomes stably stratified and for the rest of its evolution.
arxiv   +1 more source

Determining the effective temperatures of G- and K-type giants and supergiants based on observed photometric indices [PDF]

Kinematics and Physics of Celestial Bodies, 2014, Vol. 30, No. 5, pp. 244-254, 2014
A method for determining the effective temperature Teff of G- and K-type giants and supergiants is proposed. The method is based on the use of two photometric indices free from the interstellar absorption influence: the Q index in the UBV photometric system and the [c1] index in the uvby system.
arxiv   +1 more source

Resolving the delta Andromedae spectroscopic binary with direct imaging [PDF]

, 2015
We present a direct image of the innermost companion to the red giant delta Andromedae using the Stellar Double Coronagraph at the Palomar Observatory.
Bottom, Michael, Kuhn, Jonas, Mawet, Dimitri, Mennesson, Bertrand, Serabyn, Eugene, Shelton, Jean C., Wallace, J. Kent   +6 more
core   +2 more sources

Surface magnetic fields on two accreting T Tauri stars: CV Cha and CR Cha [PDF]

, 2009
We have produced brightness and magnetic field maps of the surfaces of CV Cha and CR Cha: two actively accreting G and K-type T Tauri stars in the Chamaeleon I star-forming cloud with ages of 3-5 Myr.
A. Collier Cameron, Ardila, B. D. Carter, Bally, Barnes, Bary, Bouvier, Bouvier, C. Dougados, Camenzind, Collier Cameron, Collier Cameron, Covino, D'Antona, Donati, Donati, Donati, Donati, Donati, Donati, Donati, Donati, Donstone, Ercolano, Favata, Feigelson, G. A. J. Hussain, G. Aulanier, Gauvin, Gregory, Guenther, H. C. Stempels, Hatzes, Herbst, Herczeg, Hussain, Igea, J. Bouvier, J. Ferreira, J. Ramirez Velez, J.-F. Donati, Jardine, Johns-Krull, Kupka, Kurucz, Kurucz, Königl, Luhman, M. M. Jardine, M. Semel, Marconi, Mathys, Morin, N. Dunstone, Natta, Natta, Palla, Rebull, Reiners, Reipurth, Robrade, Schegerer, Semel, Shevchenko, Shu, Siess, Skelly, Stempels, T. Harries, Unruh, Unruh, Valenti, W. A. Lawson, Wade, Wichmann   +74 more
core   +5 more sources

Spectroscopy of hot subdwarf binaries

Open Astronomy, 2018
We present a status report of our spectroscopic analysis of subdwarf binaries consisting of a subdwarf and a F/G/K-type main-sequence companion. These systems selected from SDSS photometry show significant excess in the (infra-)red which can not be ...
Kreuzer Simon, Irrgang Andreas, Heber Ulrich   +2 more
doaj   +1 more source

Multiplicity among solar-type stars IV. The CORAVEL radial velocities and the spectroscopic orbits of nearby K dwarfs [PDF]

A&A 619, A81 (2018), 2018
Context. The statistical properties of binary stars are clues for understanding their formation process. A radial velocity survey was carried on amongst nearby G-type stars and the results were published in 1991. Aims. The survey of radial velocity measurements was extended towards K-type stars. Methods.
arxiv   +1 more source

Relative abundances of CO2, CO, and CH4 in atmospheres of Earth-like lifeless planets [PDF]

, 2023
Carbon is an essential element for life on Earth, and the relative abundances of major carbon species (CO2, CO, and CH4) in the atmosphere exert fundamental controls on planetary climate and biogeochemistry. Here, we employed a theoretical model of atmospheric chemistry to investigate diversity in the atmospheric abundances of CO2, CO, and CH4 on Earth-
arxiv   +1 more source

The variation of tidal dissipation in the convective envelope of low-mass stars along their evolution [PDF]

, 2015
Since 1995, more than 1500 exoplanets have been discovered around a large diversity of host stars (from M- to A-type stars). Tidal dissipation in stellar convective envelopes is a key actor that shapes the orbital architecture of short-period systems ...
Mathis, S.
core   +4 more sources

INVESTIGATION OF COMPONENTS OF THE BINARY SYSTEM 38 PER

Odessa Astronomical Publications, 2017
Radial velocities VT of components of the binary system 38 Per are measured using high resolution and high signal / noise ratio spectra. The orbital elements were updated on the basis of these data and early published measurements of Vr.
L. S. Lyubimkov, T. M. Rachkovskaya, S. I. Rostopchin, A. E. Tarasov   +3 more
doaj   +1 more source

The rotational broadening and the mass of the donor star of GRS 1915+105 [PDF]

Astron.Astrophys. 414 (2004) L13-L16, 2003
The binary parameters of the microquasar GRS 1915+105 have been determined by the detection of Doppler-shifted 12CO and 13CO lines in its K-band spectrum (Greiner et al., 2001, Nature, 414, 522). Here, we present further analysis of the same K-band VLT spectra and we derive a rotational broadening of the donor star of V sin i=26+-3 km/s from the 12CO ...
arxiv   +1 more source