Results 31 to 40 of about 173,010 (211)

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

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

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

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

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

Chromosphere of K giant stars Geometrical extent and spatial structure detection

, 2011
We aim to constrain the geometrical extent of the chromosphere of non-binary K giant stars and detect any spatial structures in the chromosphere. We performed observations with the CHARA interferometer and the VEGA beam combiner at optical wavelengths ...
A. Spang, Andretta, Ayres, B. Pichon, Baines, Berio, Bonneau, Brown, Busà, C. Farrington, Carpenter, Chen, Claret, Cuntz, Cuntz, D. Bonneau, D. Mourard, di Benedetto, Diaz-Cordoves, Dyck, Eaton, Eriksson, F. Thévenin, Gustafsson, H. McAlister, Hall, Houdashelt, I. Tallon-Bosc, J. M. Clausse, J. Sturmann, Judge, K. Perraut, Kovacs, L. Sturmann, Linsky, Luck, Massarotti, McWilliam, Meilland, Montes, Morel, Mourard, Mozurkewich, N. Nardetto, N. Turner, O. Chesneau, O. Delaa, P. Berio, P. J. Goldfinger, P. Stee, Perryman, Pietrinferni, R. Ligi, Reimers, Richichi, Simon, Skrutskie, T. Merle, T. ten Brummelaar, ten Brummelaar, van Belle, van Leeuwen, White   +62 more
core   +3 more sources

Extrasolar planets, stellar winds and chromospheric hotspots [PDF]

Monthly Notices of the Royal Astronomical Society: Letters, 2006
Abstract Recent observations have shown what is believed to be planet-induced chromospheric activity on stars with hot Jupiters. We present a model of the magnetic interaction between a planet and a star with a dipolar magnetic field. Reconnection between the fields of the star and planet accelerates electrons along the field lines that ...
T. McIvor, M. Jardine, V. Holzwarth
openaire   +1 more source

Comparison of Solar Imaging Feature Extraction Methods in the Context of Space Weather Prediction With Deep Learning‐Based Models

Journal of Geophysical Research: Machine Learning and Computation, Volume 2, Issue 3, September 2025.
Abstract Recently, many machine learning‐based models have been developed to predict geomagnetic activity several days in advance directly from space‐borne solar imaging. To better understand and improve these models, we compare dimensionality reduction techniques to extract abstract features from solar images for space weather‐related downstream tasks.
Maria Tahtouh, Guillerme Bernoux, Antoine Brunet, Denis Standarovski, Gautier Nguyen, Angélica Sicard   +5 more
wiley   +1 more source

Physical Parameters and Chromospheric Activity of Eclipsing Binaries Observed by the LAMOST DR10 Survey

The Astrophysical Journal Supplement Series
In this study, we present a comprehensive study of more than 50,000 spectra of 32,257 eclipsing binaries from the LAMOST DR10 survey, including 5200 systems with spectroscopy.
Ansong Shi, Li-yun Zhang, Tianhao Su, Yinpeng Wang, Qi An, Xianming L. Han, Prabhakar Misra, Linyan Jiang, Rui Guo, Qingfeng Pi   +9 more
doaj   +1 more source

In the Trenches of the Solar–Stellar Connection. VII. Wilson–Bappu 2022

The Astrophysical Journal Supplement Series, 2023
The Wilson–Bappu effect (WBE) is a remarkable correlation between the width of the chromospheric emission core of the Ca ii 3934 Å K line and stellar absolute visual magnitude over an astonishing range, from diminutive red dwarfs to bloated yellow ...
Thomas Ayres
doaj   +1 more source