Stellar coronas, X-rays, and Einstein

Journal Article · Sun Jul 01 04:00:00 EDT 1984 · Sky Telesc.; (United States)

OSTI ID:6543886

Stern, R A

Observations of the sun at ultraviolet and X-ray wavelengths reveal a structure connected with the configuration of the solar magnetic field. The Einstein Observatory (HEAO 2), the first satellite to use an imaging X-ray telescope, searched for faint coronas on the basis of visual brightness and their proximity to the sun. Observed temperatures of transition regions between the chromosphere and the corona exceed 1,000,000 K. A possible correlation between X-ray luminosity and rotation rate has been observed and Einstein observations also indicated that stellar coronas showed changes in X-ray brightness during the most stable period of a star's life. Solar flares and transients, which generate substantial amounts of X-rays, radio waves and charged particles, are believed to be other properties of stellar coronas which change with age. Future missions such as NASA's Extreme Ultraviolet Explorer, the Advanced X-ray Astrophysics Facility and Space Telescope will enable astronomers to greatly increase their sampling of stellar coronas available for study. Observations also suggest the early development of a strong stellar dynamo due to X-ray activity in pre-main-sequence objects. It is hoped that the study of activity cycles in other stars will yield a greater understanding of the dynamo theory.

• Research Organization: Lockheed Research Laboratories, Palo Alto, CA
• OSTI ID: 6543886
• Journal Information: Sky Telesc.; (United States), Journal Name: Sky Telesc.; (United States) Vol. 68; ISSN SKTEA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
ELECTROMAGNETIC RADIATION
EXTREME ULTRAVIOLET RADIATION
MAGNETIC FIELD CONFIGURATIONS
RADIATIONS
SOLAR ACTIVITY
SOLAR CORONA
SOLAR X-RAY BURSTS
STAR CLUSTERS
STELLAR ATMOSPHERES
STELLAR CORONAE
ULTRAVIOLET RADIATION