Limb-brightening curves of XUV transition zone lines in the quiet Sun and in a polar coronal hole observed from Skylab
Solar limb-brightening curves are discussed for XUV spectral lines formed in the upper chromosphere and transition zone of a quiet Sun region and a polar coronal hole. The spectra were recorded by the NRL slit spectrograph on Skylab. The lines considered are emitted from ions formed within the temperature range from 10$sup 4$ K to 2.2x10$sup 5$ K. The limb-brightening curves cover a region from -4'' within the limb (1''approx. =725 km) to +20'' above the limb. The data from 0'' to +20'' are compared with predictions based on both homogeneous and inhomogeneous models of the transition zone. The limb- brightening curve of the O i line at 1355.6 A indicates that O i is formed in spicules. The limb brightening of the He ii line at 1640.4 A is consistent with a temperature of formation between approx.4x10$sup 4$ K and approx.9x10$sup 4$ K for He ii. (AIP)
- Research Organization:
- E. O. Hulburt Center for Space Research, Naval Research Lab., Washington, DC
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-33-024091
- OSTI ID:
- 4049592
- Journal Information:
- Astrophys. J., Lett., v. 202, no. 3, pp. L151-L154, Other Information: Orig. Receipt Date: 30-JUN-76
- Country of Publication:
- United States
- Language:
- English
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