Abstract. High-resolution spectroscopic observations of the eclipsing RS CVn-type active close binaries SV Camelopardalis and XY Ursae Majoris reveal excess emission components in the Hα and Hβ lines. We have used the spectral subtraction technique to separate the excess emission from the photospheric background and find that in both stars the excess emission is associated with the secondary, cooler component. Analysis of the EWHα/EW Hβ ratio indicates that in both cases the emission is probably associated with surface plage regions or prominences viewed against the stellar disks. We find no evidence of excess absorption features associated with extended prominence-like material in these systems.
Selecting the future site for a large Turkish radio telescope is a key issue. The National Radio Astronomy Observatory is now in the stage of construction at a site near Karaman City, in Turkey. A single-dish parabolic radio antenna of 30-40 m will be installed near a building that will contain offices, laboratories, and living accommodations. After a systematic survey of atmospheric, meteorological, and radio frequency interference (RFI) analyses,
Astrophysical parameters (age, reddening, distance, radius, luminosity function, mass function, total mass, relaxation time and mass segregation) have been estimated for open clusters NGC 2571, NGC 6802, Koposov 53 and Be 89 by using the Two Micron All Sky Survey(2MASS) photometry. We analyse the color-magnitude diagrams and stellar radial density profiles. We have found that NGC 2571 is the youngest one having young main sequence stars while Be 89 is the oldest cluster.
Photoelectric UBV observations, made in 1981 and 1982, of the active star HR 1362 are presented. A period analysis reveals many (all greater than 100 days) probable periods because of the large gaps in the data. If the most probable period around 330 d is true and represents the rotation period, as it does in all other active stars, then HR 1362 would be an extreme case of slow rotation.
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