Golub, Leon Harvard-Smithsonian Center for Astrophysics, Smithsonian Astrophysical Observatory, Cambridge, Massachusetts.
- Links to Primary Literature
- Additional Readings
The outer atmosphere of the Sun. The corona is characterized by extremely high temperatures of several million kelvins, which cause it to extend far above the denser surface regions of the Sun. Coronal gas is constrained to follow the magnetic field of the Sun, forming it into the shapes seen during a solar eclipse, with a coronagraph, or in x-rays. These shapes include long streamers that penetrate interplanetary space, looplike tubes over the strongest fields, and vast regions of very low density called coronal holes. Near the north and south poles, the coronal polar rays resemble the pattern formed by iron filings near a bar magnet, but at mid-latitudes, the more complicated fields of active regions dominate. The corona is hot enough to emit x-rays, and x-ray telescopes in space can form images of the corona. Such images display the magnetic loops connecting bright regions in the lower corona, while visible-light observations can detect the corona above the edge of the solar disk by carefully blocking out the strong photospheric light with an occulting disk. See also: Coronagraph; Eclipse; Solar magnetic field; X-ray astronomy
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information