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Author Lemen, J. R. ♦ Mewe, R. ♦ Schrijver, C. J. ♦ Fludra, A.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ BINARY STARS ♦ X-RAY SPECTRA ♦ MATHEMATICAL MODELS ♦ MORPHOLOGY ♦ SATELLITES ♦ SOFT X RADIATION ♦ SPECTROMETERS ♦ SPECTROSCOPY ♦ STELLAR ACTIVITY ♦ STELLAR CORONAE ♦ ATMOSPHERES ♦ ELECTROMAGNETIC RADIATION ♦ IONIZING RADIATIONS ♦ MEASURING INSTRUMENTS ♦ RADIATIONS ♦ SPECTRA ♦ STARS ♦ STELLAR ATMOSPHERES ♦ X RADIATION ♦ Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources
Abstract EXOSAT soft X-ray spectra of three binary systems of cool stars are analyzed: Capella (G6 III + F9 III), Sigma-squared CrB (F8 V + G1 V), and Procyon (F5 IV-V + DF). The EXOSAT transmission grating spectrometer permits the study of individual spectral lines and line complexes between 10 and 200 A with approximately 3 A resolution. First it is demonstrated that the spectra can be described reasonably well by a two-temperature model corona. Then the assumption that only two temperatures exist in the stellar coronas is relaxed and differential emission measure distributions are derived from the three spectra. The results from the multithermal modeling are consistent with those of the two-temperature models: emission from the coronas of each of the three stars is dominated by plasma in two relative narrow temperature intervals. These intervals are centered on 5 MK and 25 MK in the cases of Capella and Sigma-squared CrB, and 0.6 MK and 3 MK in the case of Procyon. The implications of the results for the structure of stellar coronas are briefly discussed. 41 refs.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 1989-06-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 341


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