Results 81 to 90 of about 1,834 (171)

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

Stellar Coronae And Chromospheres In The Era Of Asteroseismology

, 2018
Stellar magnetic activity is an important parameter to study as it can give insights into stellar activity cycles and even how the stellar dynamo operates. However, as cool stars evolve along the main sequence, they lose angular momentum due to magnetic braking.
Booth, R. S., Poppenhaeger, K., Watson, C. A., Silva Aguirre, V., Stello, D., Wolk, S. J.   +5 more
openaire   +2 more sources

Chromospheric and Coronal Indicators of Stellar Magnetic Structure [PDF]

Symposium - International Astronomical Union, 1983
This paper discusses attempts to derive information on magnetic structure in late-type stars, only from emission fluxes in the cores of the Ca II H and K lines, in UV emission lines and in soft X-rays — and from relations between these emission fluxes. However simpleminded and indirect this approach may seem, it brings out stimulating results.
openaire   +1 more source

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

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

Inhomogeneity in the Local ISM and Its Relation to the Heliosphere. [PDF]

Space Sci Rev, 2022
Linsky J, Redfield S, Ryder D, Moebius E.   +3 more
europepmc   +1 more source

Chromospheric dust formation, stellar masers and mass loss [PDF]

A multistep scenario which describes a plausible mass loss mechanism associated with red giant and related stars is outlined. The process involves triggering a condensation instability in an extended chromosphere, leading to the formation of cool, dense ...
Stencel, R. E.
core   +1 more source

Reconstructing Intrinsic Stellar Noise with Stellar Atmospheric Parameters and Chromospheric Activity

The Astrophysical Journal Supplement Series
Abstract Accurately characterizing the intrinsic stellar photometric noise induced by stellar astrophysics, such as stellar activity, granulation, and oscillations, is of crucial importance for detecting transiting exoplanets. In this study, we investigate the relation between the intrinsic stellar photometric noise, quantified by the ...
Jinghua Zhang, Maosheng Xiang, Jie Yu, Jian Ge, Ji-Wei Xie, Hui Zhang, Yaguang Li, You Wu, Chun-Qian Li, Shaolan Bi, Hong-Liang Yan, Jian-Rong Shi   +11 more
openaire   +3 more sources

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

IUE spectra of F and late A stars [PDF]

The International Ultraviolet Explorer (IUE) spectra of alpha CMi (F5 IV-V), beta Cas (F2 IV), alpha Car (F0 Ib), and gamma Boo (A7 III) in the context of the question as to whether chromospheres disappear in the early F late A portions of the ...
Linsky, J. L., Marstad, N. C.
core   +1 more source