Multiwavelength observations of Lindroos binary systems

Huélamo, N., Neuhäuser, R., Stelzer, B., Supper, R., Fernández, M., and Zinnecker, H.
Birth and Evolution of Binary Stars, Poster Proceedings of IAU Symposium No. 200 on The Formation of Binary Stars, held 10-15 April, 2000, in Potsdam, Germany. Edited by Bo Reipurth and Hans Zinnecker, 2000, p. 88.


We present a study of the X-ray emission from Lindroos binary systems as observed by the ROSAT satellite. These binary systems are visual pairs comprised of an early-type primary and a late-type secondary. Their ages range between 10 and 100 Myrs so, if physically bound, the secondary stars are Post-T Tauri star candidates. We have detected strong X-ray emission from most of the Lindroos secondaries under study. Their X-ray emission is comparable to that reported for young late-type stars. This fact together with the presence of the Li I (6708 Å ) absorption line in their spectra, provides clear evidence of youth among the Lindroos sample. New optical and infrared data of these objects have been already taken and will allow us to estimate more precisely their ages and their spectral energy distributions.