OPACITY PROPERTIES OF SUNSPOTS,
Abstract
Three sunspot models are considered with respect to their transparency properties. The optical radius is calculated as function of the vertical optical depth. At vertical optical depth 0.7 the three spot models considered give (horizontal) optical radii equal to 130,0.7 and 0.055, respectively. It is pointed out that the vertical temperature distribution cannot be deduced from the observations of the umbra intensity as function of spot position without taking the finite size of the spot into account, unless the opacity in the spot is relatively high. Our results indicate that the umbra is about as opaque as the photosphere. Otherwise the surrounding hotter regions would be observable through the umbra when the spot is situated away from the disk centre. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1965
- Accession Number
- AD0632170
Entities
People
- Eberhart Jensen
- Per Maltby
Organizations
- University of Oslo