Hostname: page-component-8448b6f56d-wq2xx Total loading time: 0 Render date: 2024-04-18T09:24:21.631Z Has data issue: false hasContentIssue false
  • English
  • Français

The Sun in Time: Evolution of Coronae of Solar-Type Stars

Published online by Cambridge University Press:  12 April 2016

Manuel Güdel  and
Edward F. Guinan
Manuel Güdel
Affiliation:
Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland, and JILA, University of Colorado, Boulder, CO 80309-0440
Edward F. Guinan
Affiliation:
Department of Astronomy and Astrophysics, Villanova University, Villanova, PA 19085

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We report on the results of a multi-frequency program to study coronal X-ray, EUV, and microwave activity of solar-type (G0-5 V) stars of greatly different ages. These stars are of interest as proxies for the Sun for ages from 50 Myr to 10 Gyr. Coronal temperatures decrease with X-ray/EUV luminosity and with increasing age and rotation period according to power-law relations. The young Sun had an extremely luminous corona with LEUV,X = 100 − 600LEUV,X (present Sun) and temperatures up to 10 MK; this information is pivotal for the study of the young planetary atmospheres. The findings further suggest an intimate connection between the presence of very hot coronal plasma and non-thermal radio-emitting particles.

Type
XII. The Solar/Stellar Connection in the EUV
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 519 - 524
Copyright
Copyright © Kluwer 1996

References

Canuto, V.M., Levine, J.S., Augustsson, T.R. & Imhoff, C.L. 1982, UV radiation from the young Sun and oxygen and ozone levels in the prebiological paleoatmosphere, Nature, 296, 816 Google Scholar
Dempsey, R.C., Linsky, J.L., Schmitt, J.H.M.M. & Fleming, T.A. 1993, The ROSAT All-Sky Survey of active binary coronae II: Coronal temperatures of the RS Canum Venaticorum Systems, ApJ, 413, 333 Google Scholar
Dorren, J.D. & Guinan, E.F. 1994, The Sun in Time: Detecting and Modelling Magnetic Inhomogeneities on Solar-type Stars, in The Sun as a Variable Star, IAU Colloq. 143, ed. Pap, J.M. et al., Cambridge, 206 Google Scholar
Dorren, J.D., Guinan, E.F. & Dewarf, L.E. 1994, The Decline of Solar Magnetic Activity with Age, in The 8th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, ed. Caillault, J.-P., ASP Conf. Ser., 64, 399 Google Scholar
Dorren, J.D., Güdel, M., & Guinan, E.F. 1995, X-Ray Emission from the Sun in its Youth and Old Age, ApJ, in pressGoogle Scholar
Güdel, M., Schmitt, J.H.M.M. & Benz, A.O. 1994, Discovery of microwave emission from four nearby solar-type G stars, Science, 265, 933 Google Scholar
Güdel, M., Schmitt, J.H.M.M., Benz, A.O. & Elias, N.M. II 1995a, The corona of the young solar analog EK Draconis, A&A, in pressGoogle Scholar
Güdel, M., Schmitt, J.H.M.M. & Benz, A.O. 1995b, Microwave emission from X-ray bright solar-like stars: The F-G main-sequence and beyond, A&A, in pressGoogle Scholar
Jordan, C. & Montesinos, B. 1991, The dependence of coronal temperature son Rossby numbers, MNRAS, 252, 21P Google Scholar
Raymond, J.C. & Doyle, J.G. 1981, Emissivities of strong ultraviolet lines, ApJ, 245, 1141 Google Scholar
Schrijver, C.J., Mewe, R. & Walter, F.M. 1984, Coronal activity in F-, G-, and K-type stars II: Coronal structure and rotation, A&A, 138, 258 Google Scholar
Skumanich, A. 1972, Time-scales for Ca II emission decay, rotational braking, and lithium depletion, ApJ, 171, 565 Google Scholar