Stellar Chromospheric Activity

by: Jeffrey C. Hall

The Sun, stars similar to it, and many rather dissimilar to it, have chromospheres, regions classically viewed as lying above the brilliant photosphere and characterized by a positive temperature gradient and a marked departure from radiative equilibrium. Stellar chromospheres exhibit a wide range of phenomena collectively called activity, stemming largely from the time evolution of their magnetic fields and the mass flux and transfer of radiation through the complex magnetic topology and the increasingly optically thin plasma of the outer stellar atmosphere. In this review, I will (1) outline the development of our understanding of chromospheric structure from 1960 to the present, (2) discuss the major observational programs and theoretical lines of inquiry, (3) review the origin and nature of both solar and stellar chromospheric activity and its relationship to, and effect on, stellar parameters including total energy output, and (4) summarize the outstanding problems today.

Tags: Chromospheres, Stars, Sun

This entry was posted on Monday, March 10th, 2008 at 2:00 am and is filed under Solar-Stellar Connection. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.