Binary nature and elemental abundances of 2 Lyn and HD 169981

We analyse high-resolution spectrograms of the early A-type stars HD 169981 and 2 Lyn. For the spectroscopic and photometric binary HD 169981 we determine the abundances of certain chemical elements. The derived atmospheric parameters show the star to be an A giant. The abundances of the elements Mg, Si, Ti, Cr, and Fe are very close to solar, only C and O show slight underabundances. 2 Lyn has been primarily studied for the occurrence of radial velocity variations. The star is probably a spectroscopic binary with a period of about 3.6 years. Preliminary orbital elements are derived. The search for shorter radial velocity variations gives hints of periods of 69.2, 1.56 and 1.53 days. Both of the last-mentioned periods are in the order of the expected rotation period of the star. The stellar parameters are estimated and for certain elements we determined the abundances.

The research is based on spectroscopic observations made with the 2-m telescope at the Thüringer Landessternwarte Tautenburg, Germany.