The ultraviolet spectrum of solar analogs.

Abstract

The ultraviolet high resolution IUE spectrum between 2600 and 3200 A of a sample of stars classified as solar analogs by Hardorp (1982 and references therein), including the southern solar twin HR 2290, is studied. A list of Fe II absorption line identifications and equivalent widths in the considered spectral region is presented. An analysis of the Mg II 2800 A emission doublet and of the Fe II absorption spectrum is performed and the results are discussed in terms of Hardorp's solar analogy class. It turns out that, while the Hardorp-class-1 analog (HR 2290) shows chromospheric Mg II and photospheric Fe II features close to the sun, for the other analogy classes no direct correspondence seems to exist either with the Mg II emission or with the Fe II absorption spectrum.