Titre du document

Stellar analogs of solar magnetic activity

Lien vers le document
Nom du Corpus

AstroConcepts

Auteur(s)
  • Robert W. Noyes
Affiliation(s)
  • Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass., U.S.A.
Résumé

The techniques and principal results of observational studies of stellar activity are summarized. Both chromospheric and coronal emission clearly track surface magnetic field properties, but it is not well known how the detailed relation between the emission and surface magnetic fields varies with spectral type. For lower Main-Sequence stars of the same spectral type, there is clear evidence of a close relationship between mean activity level and rotation period P rot. There is also less definitive evidence for a similar dependence on convective overturn time ? c , such that activity depends on the single parameter Ro = P rot/? c . For single stars, stellar rotation, and magnetic activity both decline smoothly with age. This implies a feedback between angular momentum loss rate and activity level. Temporal variations in mean stellar activity level mimic the solar cycle only for old stars like the Sun, being much more irregular for younger stars. The characteristic timescale of the variations (the ‘cycle period’) appears to depend on Ro for old stars, but shows no clear dependence on either rotation rate or spectral type for younger stars. Further data on mean activity and its variation for a large number of lower Main-Sequence stars should contribute significantly to our understanding of the causes of stellar magnetic activity.

Langue(s) du document
Anglais
Année de publication
1985
Revue

Solar Physics

Éditeur
Springer (journals)
Type de publication
journal
Type de document
research-article
Présence de XML structuré
Non
Version de PDF
1.3
Score de qualité du texte
9.568
Nom du concept
  • Asteroseismology
Catégories Science-Metrix
  • 1 - natural sciences ; 2 - physics & astronomy ; 3 - astronomy & astrophysics
Catégories Inist
  • 1 - sciences appliquees, technologies et medecines ; 2 - sciences biologiques et medicales ; 3 - sciences biologiques fondamentales et appliquees. psychologie ; 4 - invertebres
Catégories Scopus
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Space and Planetary Science
  • 1 - Physical Sciences ; 2 - Physics and Astronomy ; 3 - Astronomy and Astrophysics
Catégories WoS
  • 1 - science ; 2 - astronomy & astrophysics
Identifiant ISTEX
103DE707C2DA72621019DF07177DA0170CB34475
ark:/67375/1BB-ZG8M06R9-X
Powered by Lodex 9.4.5