Results 11 to 20 of about 269 (256)
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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On the generalized Schuster density law [PDF]
Serbian Astronomical Journal, 1998 A special case of the generalized Schuster density law for stellar systems with spherical symmetry is discussed; here the exponent in the denominator is equal to i/2 where i is a positive integer. Special attention is paid to the situation 2 ≤ i
Ninković S.
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Stellar-winds and coronas in cool stars [PDF]
International Astronomical Union Colloquium, 1980 AbstractRecent observational and theoretical results are reviewed that pertain to the presence and characteristics of stellar coronae and winds in late-type stars. It is found that stars - principally dwarfs - exist with “hot” coronae similar to the Sun with thermally driven winds.
A.K. Dupree, L. Hartmann
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Theory of Stellar Coronae [PDF]
Symposium - International Astronomical Union, 1987 X-ray observations have shown in recent years that the existence of high temperature plasmas in stellar atmospheres is far more widespread than extrapolated from preexisting theories of the solar and stellar coronae, forcing a radical change in our understanding of the mechanisms of coronal physics.
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Symposium - International Astronomical Union, 1997 The last two decades have seen the emergence of a new field in stellar astrophysics, the study of stellar coronae mostly in X-ray domain. With the advent of soft X-ray imagery X-ray emission was found from many thousands of solar-like stars. I will summarize the most important findings of X-ray surveys of late type stars and put the results in the ...
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Emission Lines of Fe xiv, Fe xv, and Fe xvi in the Extreme Ultraviolet Region 40–100 Å
The Astrophysical Journal, 2023 We report on emission spectra of iron in the extreme ultraviolet recorded at an electron density of ∼10 ^11 cm ^−3 on the Lawrence Livermore electron beam ion trap facility.
J. K. Lepson +3 more
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The FIP and Inverse FIP Effects in Solar and Stellar Coronae
Living Reviews in Solar Physics, 2015 We review our state of knowledge of coronal element abundance anomalies in the Sun and stars. We concentrate on the first ionization potential (FIP) effect observed in the solar corona and slow-speed wind, and in the coronae of solar-like dwarf stars ...
J. Martin Laming
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Highlights of Astronomy, 1980 The standard theory of stellar coronae requires the presence of vigorous surface convection. In consequence, the expectation of such a theory is that stellar x-ray emission — if due to a corona — should be limited to a subset of stars (principally those of main sequence spectral types F and G), and therefore should be relatively rare.
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The High-energy Spectrum of the Young Planet Host V1298 Tau
The Astronomical Journal, 2023 V1298 Tau is a young pre-main-sequence star hosting four known exoplanets that are prime targets for transmission spectroscopy with current-generation instruments. This work pieces together observations from the NICER X-ray telescope, the Space Telescope
Girish M. Duvvuri +6 more
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The Astrophysical Journal, 2023 The ponderomotive force has been suggested to be the main mechanism to produce the so-called first ionization potential (FIP) effect—the enrichment of low-FIP elements observed in the outer solar atmosphere, in the solar wind, and in solar energetic ...
Juan Martínez-Sykora +5 more
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