SIMBAD references

2002A&A...388L..13S - Astronomy and Astrophysics, volume 388, L13-16 (2002/6-2)

Carbon and nitrogen abundances in the coronae of Algol B and other evolved stars: Evidence for CNO-cycle processed material.


Abstract (from CDS):

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 CNO-cycle processed material at the surfaces and in the coronae of Algol and β Cet.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: activity - stars: coronae - stars: late type - X-rays: stars - stars: individual: Algol

Simbad objects: 12

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