Results from an extensive Einstein stellar survey

Journal Article · Wed Apr 01 04:00:00 EST 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158797· OSTI ID:6192637

Vaiana, G S; Cassinelli, J P; Fabbiano, G; Giacconi, R; Golub, L; Gorenstein, P; Haisch, B M; Harnden, Jr, F R; Johnson, H M; Linsky, J L; Maxson, C W; Mewe, R; Rosner, R; Seward, F; Topka, K; Zwaan, C

We report the preliminary results of the Einstein Observatory stellar X-ray survey. To date, 143 soft X-ray sources have been identified with stellar counterparts, leaving no doubt that stars in general constitute a pervasive class of low-luminosity galactic X-ray sources. We have detected stars along the entire main sequence, of all luminosity classes, pre-main sequence stars as well as very evolved stars. Early type OB stars have X-ray luminosities in the range approx.10/sup 31/ to approx.10/sup 34/ ergs s/sup -1/; late type stars show a somewhat lower range of X-ray emission levels, from approx.10/sup 26/ to approx.10/sup 31/ ergs s/sup -1/. Late type main-sequence stars show little dependence of X-ray emission levels upon stellar effective temperature; similarly, the observations suggest weak, if any, dependence of X-ray luminosity upon effective gravity. Instead, the data show a broad range of emission levels (approx.three orders of magnitude) throughout the main sequence later than F0. Comparison of the data with published theories of acoustically heated coronae shows that these models are inadequate to explain our results. The data are consistent with magnetically dominated coronae, as in the solar case.

• Research Organization: Harvard-Smithsonian Center for Astrophysics
• OSTI ID: 6192637
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 245:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DATA ANALYSIS
DIAGRAMS
HERTZSPRUNG-RUSSELL DIAGRAM
LUMINOSITY
MAIN SEQUENCE STARS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SPECTRA
STARS
STELLAR ATMOSPHERES
X-RAY SPECTRA