Results 11 to 20 of about 1,834 (171)

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.
doaj   +2 more sources

Stellar Chromospheric Variability [PDF]

Universe, 2021
Cool stars with convective envelopes of spectral types F and later tend to exhibit magnetic activity throughout their atmospheres. The presence of strong and variable magnetic fields is evidenced by photospheric starspots, chromospheric plages and ...
Richard de Grijs, Devika Kamath
doaj   +2 more sources

Evidence for Stellar Chromospheres in Globular Clusters [PDF]

Symposium - International Astronomical Union, 1987
We suggest that the conspicuous gaps frequently seen in the color-magnitude diagrams of globular clusters are caused by a sudden increase in chromospheric activity shortly after stars evolve away from the main sequence.
William Liller, Gonzalo Alcaino
openaire   +1 more source

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, Allison Youngblood, R. O. Parke Loyd, Kevin France   +3 more
doaj   +1 more source

Atmospheric Heating and Wind Acceleration: Results for Cool Evolved Stars based on Proposed Processes

, 2014
A chromosphere is a universal attribute of stars of spectral type later than ~F5. Evolved (K and M) giants and supergiants (including the zeta Aurigae binaries) show extended and highly turbulent chromospheres, which develop into slow massive winds.
A. Brown, A. Chiavassa, A. Lobel, A. Lébre, A. Skumanich, A.D. McMurry, A.K. Dupree, B. Buchholz, B. Freytag, B. Pontieu De, B. Pontieu De, B. Pontieu De, B.E. Wood, C.-H. An, C.J. Schrijver, C.J. Schrijver, D. Fawzy, D. Rabin, D. Reimers, D.E. Osterbrock, D.F. Gray, D.J. Mullan, F.P. Pijpers, G.A. Gary, G.M. Harper, G.M. Harper, G.M. Harper, H. Alfvén, H. Peter, H. Peter, I. Pagano, J. Martínez-Sykora, J. Tu, J.A. Eaton, J.A. Eaton, J.D. Jackson, J.E. Leake, J.E. Leake, J.E. Leake, J.E. Leake, J.E. Vernazza, J.E. Vernazza, J.G. Doyle, J.G. Doyle, J.H. Piddington, J.L. Linsky, J.L. Linsky, J.M. Davila, J.M. Fontenla, J.M. Fontenla, J.V. Hollweg, J.V. Hollweg, K. Eriksson, K. Ohnaka, K.-P. Schröder, K.B. MacGregor, K.G. Carpenter, K.G. Carpenter, K.G. Carpenter, K.G. Carpenter, K.G. Strassmeier, L. Hartmann, L. Hartmann, L. Ofman, L. Ofman, L.S. Anderson, M. Auriére, M. Cuntz, M. Cuntz, M. Cuntz, M. Cuntz, M. Cuntz, M. Cuntz, M. Heinemann, M. Mathioudakis, M. Mitchner, M. Velli, M.C.M. Cheung, M.I. Pérez Martínez, M.L. Goodman, M.L. Goodman, M.L. Goodman, M.L. Khodachenko, M.R. Barkhudarov, M.S. Ruderman, N. Guerreiro, P. Charbonneau, P. Petit, P. Song, P. Ulmschneider, P. Ulmschneider, P.G. Judge, P.G. Judge, P.G. Judge, P.G. Judge, P.K. Shukla, R. Grappin, R. Lundin, R. Rosner, R. Rosner, R. Soler, R.A. Kopp, R.D. Robinson, R.G.M. Rutten, R.J. Morton, R.J. Morton, R.K. Konstantinova-Antova, R.K. Konstantinova-Antova, R.W Noyes, S. Tomczyk, S.B.F. Dorch, S.I. Braginskii, S.R. Cranmer, S.R. Cranmer, S.R. Cranmer, S.R. Cranmer, T. Simon, T. Tsuji, T.D. Arber, T.E. Holzer, T.K. Suzuki, T.K. Suzuki, T.K. Suzuki, T.R. Ayres, T.R. Ayres, T.R. Ayres, T.R. Ayres, U. Narain, U. Narain, U. Torkelsson, V. Hansteen, V. Krasnoselskikh, V.H. Hansteen, V.S. Airapetian, V.S. Airapetian, V.S. Airapetian, W.C. Danchi, W.H. Matthaeus, Y.-T. Lau, Z.E. Musielak   +139 more
core   +1 more source

A Model for the Chromosphere/Wind of 31 Cygni and its Implications for Single Stars

, 2008
I develop a detailed empirical model for the chromosphere and wind of 31 Cyg based on a previously published analysis of IUE spectra from the 1993 eclipse and on the thermodynamics of how the wind must be driven.
Eaton, Joel A.
core   +1 more source

First Detection of Thermal Radio Emission from Solar-Type Stars with the Karl G. Jansky Very Large Array [PDF]

, 2014
We present the first detections of thermal radio emission from the atmospheres of solar-type stars {\tau} Cet, {\eta} Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and ...
Bourke, Stephen, Güdel, Manuel, Hallinan, Gregg, Rupen, Michael, Villadsen, Jackie   +4 more
core   +3 more sources

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
openaire   +1 more source

Dust, pulsation, chromospheres and their role in driving mass loss from red giants in Galactic globular clusters

, 2007
Context: Mass loss from red giants in old globular clusters affects the horizontal branch (HB) morphology and post-HB stellar evolution including the production of ultraviolet-bright stars, dredge up of nucleosynthesis products and replenishment of the ...
Asida, Aurière, Baron, Bates, Boyer, Cacciari, Cahn, Cioni, Cioni, Clement, Cohen, Deutsch, Dupree, Dupree, Dupree, Evans, Falceta-Gonçalves, Feast, Fluks, Fox, Frogel, Frogel, Fusi-Pecci, Gebhardt, Gratton, Gratton, Hagen, Hagen, Harris, Hartmann, Hauschildt, Hauschildt, Houdashelt, I. McDonald, Ibata, Ita, J. Th. van Loon, Judge, Kurucz, Lebzelter, Lebzelter, Lebzelter, Lebzelter, Lebzelter, Levesque, Lloyd Evans, Lloyd Evans, Lloyd Evans, Mauas, McLaughlin, Menzel, Moehler, Montegriffo, Nieuwenhuijzen, Norris, Norris, Origlia, Origlia, Pancino, Paturel, Pickles, Pijpers, Ramdani, Reimers, Rood, Rosenberg, Schröder, Schröder, Sollima, Straniero, Thomas, Valenti, van Loon, van Loon, van Loon, van Loon, Wood, Wood   +77 more
core   +1 more source

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
openaire   +1 more source