Opacity in the upper atmospheres of active stars - II. AD Leonis
Data(s) |
01/08/2006
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Resumo |
We present FUV and UV spectroscopic observations of AD Leonis, with the aim of investigating opacity effects in the transition regions of late-type stars. The C III lines in FUSE spectra show significant opacity during both the quiescent and flaring states of AD Leonis, with up to 30% of the expected flux being lost during the latter. Other FUSE emission lines tested for opacity include those of O VI, while C IV, Si IV and N V transitions observed with STIS are also investigated. These lines only reveal modest amounts of opacity with losses during flaring of up to 20%. Optical depths have been calculated for homogeneous and inhomogeneous geometries, giving path lengths of approximate to 20 - 60 km and approximate to 10 - 30 km, respectively, under quiescent conditions. However path lengths derived during flaring are approximate to 2 - 3 times larger. These values are in excellent agreement with both estimates of the small-scale structure observed in the solar transition region, and path lengths derived previously for several other active late-type stars. |
Identificador |
http://www.scopus.com/inward/record.url?scp=33746879129&partnerID=8YFLogxK |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Keenan , F , Christian , D , Mathioudakis , M , Bloomfield , S , Pollacco , D , Dupuis , J & Malina , R F 2006 , ' Opacity in the upper atmospheres of active stars - II. AD Leonis ' Astronomy and Astrophysics , vol 454 , no. 3 , pp. 889-894 . |
Palavras-Chave | #/dk/atira/pure/subjectarea/asjc/1900/1912 #Space and Planetary Science |
Tipo |
article |