ASCA Science Highlights: Stars
Follow the links to images and plotsCoronae of stars contain hot gas with temperatures of millions of degrees. The spectroscopic capability of ASCA enables scientists to study the individual emission lines of elements such as Fe, Si and S.
- Although ASCA's imaging capabilities are modest, we could still resolve YY Gem and Castor, ~1 arcmin apart, and detect flares and quiescent emissions from both.
- AR Lac is a binary star system with active coronae, which no instrument can directly image. However, using the ASCA light curve, in particular how the two stars hide the X-ray emission, scientists could map the X-ray emissions in this system.
- ASCA spectra have enabled the study of the elemental abundances in stellar coronae: iron and other heavy elements may be underabundant in the coronae of active stars. In the case of UX Ari, iron abundance was seen to increase 5-fold during a flare.
- Very young stars are shrouded by the molecular clouds in which they are forming. The hard X-ray imaging capability of ASCA has allowed observations deep into such star forming regions. See, for example, soft and hard band images and flare data of the R CrA dark cloud.
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