X-ray studies of coeval star samples. II. The Pleiades cluster as observed with the Einstein Observatory

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168263· OSTI ID:6904944

Micela, G; Sciortino, S; Vaiana, G S; Harnden, Jr, F R; Rosner, R ^[1]

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1. Osservatorio Astronomico, Palermo (Italy) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA) Chicago Univ., IL (USA)

Coronal X-ray emission of the Pleiades stars is investigated, and maximum likelihood, integral X-ray luminosity functions are computed for Pleiades members in selected color-index ranges. A detailed search is conducted for long-term variability in the X-ray emission of those stars observed more than once. An overall comparison of the survey results with those of previous surveys confirms the ubiquity of X-ray emission in the Pleiades cluster stars and its higher rate of emission with respect to older stars. It is found that the X-ray emission from dA and early dF stars cannot be proven to be dissimilar to that of Hyades and field stars of the same spectral type. The Pleiades cluster members show a real rise of the X-ray luminosity from dA stars to early dF stars. X-ray emission for the young, solarlike Pleiades stars is about two orders of magnitude more intense than for the nearby solarlike stars. 77 refs.

• OSTI ID: 6904944
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 348; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPARATIVE EVALUATIONS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DIAGRAMS
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
HERTZSPRUNG-RUSSELL DIAGRAM
IONIZING RADIATIONS
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SPATIAL DISTRIBUTION
SPECTRA
STAR CLUSTERS
VARIATIONS
X RADIATION