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Mostrando ítems 11-20 de 126
First long-term activity study of AU Microscopii: a possible chromospheric cycle
(Wiley Blackwell Publishing, Inc, 2019-02)
M stars are ideal targets to search for Earth-like planets. However, they usually have high levels of magnetic activity, which could affect their habitability and make difficult the detection of exoplanets orbiting around ...
Chromospheric Activity of Southern Stars from the Magellan Planet Search Program
(2011)
I present chromospheric-activity measurements of ~670 F, G, K, and M main-sequence stars in the Southern Hemisphere, from ~8000 archival high-resolution echelle spectra taken at Las Campanas Observatory since 2004. These ...
Hα and the Ca II H and K lines as activity proxies for late-type stars
(EDP Sciences, 2007-07)
Context.The main chromospheric activity indicator is the S index, which is the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied for stars from F to K. Another chromospheric ...
Modelling chromospheric line profiles in NGC 2808: evidence of mass loss from RGB stars
(Edp Sciences, 2006-08)
In this study we test the possibility that the asymmetry in the profiles of the Hα and Ca ii K lines in red giant stars is due to the presence of an active chromosphere rather than to mass loss. To this end, we compare ...
Chromospheric Activity of Southern Stars from the Magellan Planet Search Program
(2011)
I present chromospheric-activity measurements of ~670 F, G, K, and M main-sequence stars in the Southern Hemisphere, from ~8000 archival high-resolution echelle spectra taken at Las Campanas Observatory since 2004. These ...
Discovery of an activity cycle in the solar-analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates
(EDP Sciences, 2016-05)
Context. Most stellar activity cycles similar to that found in the Sun have been detected by using the chromospheric Ca ii H&K lines as stellar activity proxies. However, it is unclear whether such activity cycles can be ...
Semi-empirical Modeling of the Photosphere, Chromosphere, Transition Region, and Corona of the M-dwarf Host Star GJ 832
(IOP Publishing, 2016-10)
Stellar radiation from X-rays to the visible provides the energy thatcontrols the photochemistry and mass loss from exoplanet atmospheres.The important extreme ultraviolet (EUV) region (10-91.2 nm) isinaccessible and should ...