Solar Physics

, Volume 25, Issue 2, pp 413–417

Emissions ‘froides’ dans la couronne solaire

  • Jean-Louis Leroy

DOI: 10.1007/BF00192338

Cite this article as:
Leroy, JL. Sol Phys (1972) 25: 413. doi:10.1007/BF00192338


Prominences have been photographed through a coronagraph and an Hα Lyot filter with long exposure times. Faint Hα emissions are often detected down to the threshold 2 × 10-6 times of the Sun's brightness; they show definite structures but their relations to the low-level ordinary prominences are not very clear. Estimates are given for the density and thickness of such cool regions.

Copyright information

© D. Reidel Publishing Company 1972

Authors and Affiliations

  • Jean-Louis Leroy
    • 1
  1. 1.Observatoire du Pic du MidiBagnères-de-BigorreFrance