{"title":"Stellar Chromospheric Activity","authors":"Jeffrey C. Hall","doi":"10.12942/lrsp-2008-2","DOIUrl":null,"url":null,"abstract":"<p>The Sun, stars similar to it, and many rather dissimilar to it, have <i>chromospheres</i>, 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 <i>activity</i>, 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.</p>","PeriodicalId":687,"journal":{"name":"Living Reviews in Solar Physics","volume":"5 1","pages":""},"PeriodicalIF":23.0000,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrsp-2008-2","citationCount":"102","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Living Reviews in Solar Physics","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.12942/lrsp-2008-2","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 102
Abstract
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.
期刊介绍:
Living Reviews in Solar Physics is a peer-reviewed, full open access, and exclusively online journal, publishing freely available reviews of research in all areas of solar and heliospheric physics. Articles are solicited from leading authorities and are directed towards the scientific community at or above the graduate-student level. The articles in Living Reviews provide critical reviews of the current state of research in the fields they cover. They evaluate existing work, place it in a meaningful context, and suggest areas where more work and new results are needed. Articles also offer annotated insights into the key literature and describe other available resources. Living Reviews is unique in maintaining a suite of high-quality reviews, which are kept up-to-date by the authors. This is the meaning of the word "living" in the journal''s title.