Submillimeter Observations of the 1991 July 11 Total Solar Eclipse
Abstract
We present observations of the 1991 July 11 total solar eclipse at 850 microns made with the Caltech Submillimeter Observatory on Mauna Kea. We find that the 850-micron limb is 3380 +/- 140 km above the visible limb. We also find that there is a 10 percent limb brightening in the outer 7 arcsec of the solar disk, and we measure a central brightness temperature of 6400 +/- 700 K. These results require that the upper chromosphere not be in hydrostatic equilibrium, with a higher electron density than is predicted by the standard (VAL) model. We show that the dependence of limb height on wavelength is well fitted by a one-parameter model with an electron density scale height of 1200 km; there is no need to invoke complex spicule geometry to explain the observations.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1993
- DOI:
- 10.1086/172213
- Bibcode:
- 1993ApJ...403..426E
- Keywords:
-
- Solar Eclipses;
- Submillimeter Waves;
- Brightness Temperature;
- Chromosphere;
- Electron Density (Concentration);
- Solar Limb;
- Solar Radio Bursts;
- Spicules;
- Solar Physics;
- ECLIPSES;
- SUN: CHROMOSPHERE;
- SUN: RADIO RADIATION