3 papers
astro-ph1997
Chromospheric Emission from Red Giants in the Open Cluster NGC 6940
D. Barrado y Navascues, A. K. Dupree
The observation of the Ca II H and K lines in red giants in NGC 6940 allows the strength of chromospheres and their behavior to be evaluated in a population whose evolution is well…
astro-ph1997
Lithium and binarity in M67
D. Barrado y Navascues, J. R. Stauffer, S. Balachandran
A study of the lithium abundances in binaries of the old open cluster M67 is presented. Abundances were estimated using curves of growth and equivalent widths of the LiI6707.8 Å do…
astro-ph1997
Why is the X-ray luminosity function different for the Hyades and Praesepe?
D. Barrado y Navascues, J. R. Stauffer, S. Randich
We have studied dF-dK and dM stars belonging to Praesepe in order to determine membership via radial velocities and to compare several stellar properties, such as X-ray luminositie…