Results 81 to 90 of about 151,165 (141)

From theoretical stellar spectra to realistic models of the Milky Way : a never ending Odyssey [PDF]

, 2007
The last chapter is dedicated to the compilation of the results and the discussion about the success of - but also about the problems that have arisen during - and in part also survived - this work. The main goal of this thesis was, firstly, to convert
Ammon, Karin
core   +1 more source

THE PRESENT STATE OF WAVE-HEATING THEORIES OF STELLAR CHROMOSPHERES

, 1986
Observational constraints are summarized and the present state of the acoustic and mhd-wave heating theories for chromospheres in early and late-type stars are discussed.
P Ulmschneider
core  

PHOENIX model chromospheres of mid- to late-type M dwarfs

, 2005
We present semi-empirical model chromospheres computed with the atmosphere code PHOENIX. The models are designed to fit the observed spectra of five mid- to late-type M dwarfs.
J. H. M. M. Schmitt, P. H. Hauschildt, B. Fuhrmeister   +2 more
core   +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

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

Influence of chemi-ionization and chemi-recombination processes on hydrogen line shapes in M dwarfs

, 2007
Aims.We study the influence of chemi-ionization in ${\rm H}^{*}(n) + {\rm H}(1{\rm s})$ collisions and inverse chemi-recombination processes on the population of higher levels and consequently on profiles of hydrogen lines in the atmospheres of late type
Lj. M. Ignjatović, F. Alard, D. Jevremović, M. S. Dimitrijević, A. A. Mihajlov, P. Hauschildt   +5 more
core   +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

A Possible Stellar Coronal Mass Ejection Event Associated with a Long-duration Optical Flare on the RS CVn-type Star UX Arietis

The Astrophysical Journal
Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma from stellar coronae, and they are always accompanied by flares. In this study, we present high-resolution spectroscopic observations of a long-duration optical flare on the RS ...
Dongtao Cao, Shenghong Gu
doaj   +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

Doppler-shifted Signatures in the Chromospheric Line Profiles of II Pegasi

The Astrophysical Journal
Stellar flares are frequently accompanied by prominence eruptions, coronal mass ejections (CMEs), and other forms of plasma motion. Based on the long-term high-resolution spectroscopic monitoring data set of the RS CVn-type star II Pegasi (II Peg), we ...
Dongtao Cao, Shenghong Gu
doaj   +1 more source