Results 1 to 10 of about 151,165 (141)
Measuring the magnetic fields in the chromospheres of low-mass stars [PDF]
Nature CommunicationsMagnetic fields in the upper atmospheres of solar-like stars are believed to provide an enormous amount of energy to power the hot coronae and drive large-scale eruptions that could impact the habitability of planetary systems around these stars. However,
Tianqi Cang +13 more
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Stellar Chromospheric Activity [PDF]
Living Reviews in Solar Physics, 2008 The Sun, stars similar to it, and many rather dissimilar to it, have chromospheres, regions classically viewed as lying above the brilliant photosphere and characterized by a positive temperature gradient and a marked departure from radiative equilibrium.
Hall Jeffrey C.
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The Influence of Stellar Chromospheres and Coronae on Exoplanet Transmission Spectroscopy
Astrophysical Journal LettersA main source of bias in transmission spectroscopy of exoplanet atmospheres is magnetic activity of the host star in the form of stellar spots, faculae, or flares. However, the fact that main-sequence stars have a chromosphere and a corona and that these
Oded Aharonson, Aviv Ofir
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Correlating Intrinsic Stellar Parameters with Mg ii Self-reversal Depths
The Astrophysical JournalThe Mg ii h&k emission lines (2803, 2796 Å) are a useful tool for understanding stellar chromospheres and transition regions due to their intrinsic brightness, relatively low interstellar medium (ISM) absorption interference, and abundance
Anna Taylor +4 more
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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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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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Thermal Instability and the Convective Stability of Stellar Chromospheres [PDF]
, 1970 It is generally believed that stellar chromospheres are stable against convection since the Schwarzschild criterion indicates stability when temperature increases with height.
Defouw, Richard John
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