Line formation in the solar chromosphere. II - an optically thick region of the chromosphere-corona transition region observed with OSO 8
Abstract
The University of Colorado ultraviolet spectrometer aboard the Orbiting Solar Observatory 8(OSO 8) has measured self-reversed profiles of the resonance line of C IV lamda 1548.2 at the limb passage of an active region. The degree of the self-reversal together with the absolute intensity of the line profile determine the electron density in the active region at 10 to the 10th/cu cm at temperatures where the C IV line is formed. The nonthermal component of the broadening velocity is no more than 14km/s, and the physical thickness of an equivalent plane-parallel slab in hydrostatic equilibrium that would give rise to the observed line profiles is about 430 km.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1980
- DOI:
- 10.1086/157744
- Bibcode:
- 1980ApJ...236..280L
- Keywords:
-
- Chromosphere;
- Line Spectra;
- Solar Spectra;
- Ultraviolet Astronomy;
- Optical Thickness;
- Oso-8;
- Radiative Transfer;
- Ultraviolet Spectrometers;
- Solar Physics