Results 21 to 30 of about 164 (131)
Living with a Red Dwarf: X-Ray, UV, and Ca ii Activity–Age Relationships of M Dwarfs
The Astrophysical Journal, 2023 The vast majority of stars in the nearby stellar neighborhood are M dwarfs. Their low masses and luminosities result in slow rates of nuclear evolution and minimal changes to the stars’ observable properties, even along astronomical timescales.
Scott G. Engle
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HST Low-resolution Stellar Library
The Astrophysical Journal Supplement Series, 2023 In order to provide fundamental stellar spectra that extend into the UV, Hubble Space Telescope’s Space Telescope Imaging Spectrograph targeted 556 stars via proposals GO9088, GO9786, GO10222, and GO13776.
Tathagata Pal +4 more
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Is Core Angular Momentum Key to the Giant Dynamo?
Universe, 2022 The pros and cons of core angular momentum dissipation into the convective envelopes of giants as a driver of giant activity is discussed in face of the observational evidence, which points to two ”magnetic strips“, in the HRD, where in the first, at the
Klaus-Peter Schröder +1 more
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Modeling the Chromosphere and Transition Region of Planet-hosting Star GJ 436
The Astrophysical Journal, 2023 Ahead of upcoming space missions intending to conduct observations of low-mass stars in the ultraviolet (UV) spectral region it becomes imperative to simultaneously conduct atmospheric modeling from the UV to the visible (VIS) and near-infrared (NIR ...
Dominik Hintz +14 more
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Stellar model chromospheres. IX - Chromospheric activity in dwarf stars
The Astrophysical Journal, 1979 High-resolution Ca II K line profiles are used to model the upper photospheres and lower chromospheres of eight main-sequence stars ranging in spectral type from F0 to M0 and exhibiting different degrees of chromospheric activity. The model chromospheres are studied as a function of spectral type and activity for stars of similar spectral type in order
W. L. Kelch, S. P. Worden, J. L. Linsky
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New and Improved Lyα Reconstructions for M and K Dwarfs
The Astrophysical Journal, 2023 The Ly α emission line is the brightest UV emission line in M and K dwarf spectra and serves as an important tool for studies of stellar chromospheres, the interstellar medium, and exoplanet atmospheres.
Angeli Sandoval +3 more
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Detection of mass loss in stellar chromospheres
The Astrophysical Journal, 1980 IUE observations of 47 cool giants have been made in a search for the onset of expansion in the Mg II h and k emission cores. It is found that, in a statistical sense, the longward emission peak becomes dominant above a velocity dividing line in the H-R diagram, which lies close to a temperature dividing line reported by Linsky and Haisch (1979).
R. E. Stencel, D. J. Mullan
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Journal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 3, June 2026.Abstract Recent advances in solar physics increasingly rely on automated identification of coronal structures using machine learning. Yet most studies emphasize scientific performance without evaluating feasibility for onboard deployment to prioritize downlink observations.
P. Gonidakis +11 more
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The Magnetic Field Configuration in Solar and Stellar Chromospheres [PDF]
Symposium - International Astronomical Union, 1983 Calculations are presented for the inhomogeneous magnetic field structure above a stellar photosphere which has magnetic flux tubes located at the downdraughts of its supergranulation pattern. Regions can be delineated where the ambient magnetic energy density is large or small compared with the thermal energy density derived from a model atmosphere ...
U. Anzer, D. J. Galloway
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Advancing Heliophysics and Space Weather Modeling Through Open Science
Space Weather, Volume 24, Issue 6, June 2026.Abstract We present a community‐wide effort to develop a strategy and action plan to advance heliophysics and space weather modeling through open science. While open science has the potential to enhance the quality and pace of scientific discovery, its application to scientific modeling requires more careful consideration regarding open data and open ...
C. Corti +87 more
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