Volume 388, Number 1, June II 2002
|Page(s)||L13 - L16|
|Published online||28 May 2002|
Letter to the Editor
Carbon and nitrogen abundances in the coronae of Algol B and other evolved stars: Evidence for CNO-cycle processed material
Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
Corresponding author: J. H. M. M. Schmitt, firstname.lastname@example.org
Accepted: 10 April 2002
Using the Lyα-lines of carbon and nitrogen measured in Chandra Low Energy Transmission Grating Spectrometer (LETGS) spectra we study the coronal abundances of these elements in a sample of late-type stars including dwarf stars, the prototypical eclipsing binary Algol, the single giant β Cet, and three RS CVn binaries. In the main sequence stars of our sample the flux ratio RNC between the Lyα-lines of nitrogen and carbon is below unity, while RNC is found to be ≈8.5 for β Cet and >23.3 for Algol. These values are more than an order of magnitude larger than expected from a solar abundance plasma in collisional equilibrium regardless of the chosen temperature structure. We therefore interpret the anomalously large RNC-ratios as being due to the exposure of processed material at the surfaces and in the coronae of Algol and β Cet.
Key words: stars: abundances / stars: activity / stars: coronae / stars: late type X-rays: stars / stars: individual: Algol
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.