Results 91 to 100 of about 173,010 (211)

An IUE's eye view of cool-star outer atmospheres [PDF]

Three topics are discussed which together demonstrate the power of the IUE to probe the occurrences of chromospheres and coronas in the cool half of the HR diagram.
Ayres, T. R.
core   +1 more source

Stellar Model Chromospheres. H. Procyon (F5 Iv/v)

The Astrophysical Journal, 1974
Derivation of a model for the chromosphere and upper photosphere of Procyon (F5 IV-V) based on calibrated observations of the K and 8542-A lines of Ca II, the k(2796-A) line of Mg II, and the K-line wings. The feasibility of this model synthesis approach to derive a preliminary model chromosphere is demonstrated despite the lack of spatial and ...
Thomas R. Ayres, Jeffrey L. Linsky, Richard A. Shine   +2 more
openaire   +1 more source

The Mg 2 h and k lines in a sample of dMe and dM stars [PDF]

Both Mg II h and k line fluxes are presented for a sample of 4 dMe and 3 dM stars obtained with the IUE satellite in the long wavelength, low dispersion mode.
Ayres, T. R., Giampapa, M. S., Linsky, J. L., Pornmann, P. L., Worden, S. P.   +4 more
core   +1 more source

Constraints on the ionizing flux emitted by T Tauri stars

, 2005
We present the results of an analysis of ultraviolet observations of T Tauri Stars (TTS). By analysing emission measures taken from the literature we derive rates of ionizing photons from the chromospheres of 5 classical TTS in the range ~10^41-10^44 ...
Adams, Alexander, Alexander, Ardila, Armitage, Arnaud, Arnaud, Ayres, Basri, Beckwith, Bouret, Brooks, Brooks, C. J. Clarke, Calvet, Cardelli, Clarke, Cohen, Costa, Damiani, Dere, Feigelson, Fludra, Font, Gahm, Gullbring, Gullbring, Haisch, Hartigan, Hartigan, Hartmann, Herczeg, Hollenbach, Hollenbach, Imhoff, J. E. Pringle, Johns-Krull, Jordan, Kenyon, Kitamura, Kravtsova, Lago, Lamzin, Linsky, Linsky, Mahdavi, Mannings, Mason, Mathieu, Matsuyama, Palla, R. D. Alexander, Richling, Ruden, Shang, Skrutskie, Stezler, Strom, Travisano, Unruh, Valenti, Valenti, Wyatt, Young, Zirin   +64 more
core   +2 more sources

Lyα Emission from K and M Dwarfs: Intrinsic Profiles, Variability, and Flux in the Habitable Zone

The Astrophysical Journal
Lyman-alpha (Ly α ) is the most prominent ultraviolet (UV) emission line in low-mass stars, playing a crucial role in exoplanet atmospheric photochemistry, heating, and escape.
Sarah Peacock, Travis S. Barman, R. O. Parke Loyd, Adam C. Schneider, Allison Youngblood, Kenneth G. Carpenter, Evgenya L. Shkolnik   +6 more
doaj   +1 more source

Evidence for extended chromospheres surrounding red giant stars [PDF]

Observational evidence and theoretical arguments are summarized which indicate that regions of partially ionized hydrogen extending several stellar radii are an important feature of red giant and supergiant stars.
Stencel, R. E.
core   +1 more source

The non-active stellar chromosphere: Ca ii basal flux★ [PDF]

, 2014
M. Isabel Pérez Martínez, K.‐P. Schröder, P. H. Hauschildt   +2 more
openalex   +1 more source

HWO Target Stars and Systems: A Survey of Archival UV and X-Ray Data

The Astronomical Journal
We assess archival high-energy data for key stars on the Habitable Worlds Observatory (HWO) Target Stars and Systems 2025 list, as stellar radiation is critical to shaping and interpreting planetary atmospheres.
Sarah Peacock, David J. Wilson, Tyler Richey-Yowell, Noah W. Tuchow, Kevin France, José A. Caballero, Riccardo Spinelli, Lía Corrales, Aiden S. Zelakiewicz, Seth Redfield, Keighley Rockcliffe, Allison Youngblood, Cynthia S. Froning, Girish M. Duvvuri, Breanna A. Binder, Natalie R. Hinkel, Eric E. Mamajek   +16 more
doaj   +1 more source

Observation of winds in cool stars [PDF]

, 1983
Sufficient observational material - ultraviolet spectroscopic measures, quantitative optical spectroscopy, and X-ray photometry exists to enable discernment of the presence and character of mass loss in cool stars and to establish meaningful constraints ...
Dupree, A. K.
core   +1 more source

High Lithium Abundance Connection with the Chromospheric Helium in Red Giants: Spectroscopic and Asteroseismic Analyses

The Astrophysical Journal
We present a study of correlations between high Li abundances and strong chromospheric He i λ 10830 absorption-line strengths in Kepler field giant stars.
Anohita Mallick, Christopher Sneden, Bacham E. Reddy, Melike Afşar   +3 more
doaj   +1 more source