Results 11 to 20 of about 334 (164)
The Astrophysical Journal Supplement Series, 2022 Stellar parameters and magnetic activity are important for the understanding of stellar physics and dynamo theory. We have used LAMOST spectroscopic surveys to study stellar parameters and magnetic activity properties of TESS objects.
Li-yun Zhang +6 more
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Stellar Convection Zones, Chromospheres, and Rotation
The Astrophysical Journal, 1966 O. C. Wilson
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Stellar chromospheres - H-alpha and CA II K profiles [PDF]
The Astrophysical Journal Supplement Series, 1983 D. M. Zarro, A. W. Rodgers
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Modeling Stellar Ca ii H and K Emission Variations: Spot Contribution to the S-index
The Astrophysical Journal Letters, 2023 The S -index is a measure of emission in the Ca ii H and K lines and is a widely used proxy of stellar magnetic activity. It has been assumed until now that the S -index is mainly affected by bright plage regions in the chromosphere.
K. Sowmya +4 more
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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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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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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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