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Full-Text Articles in Physical Sciences and Mathematics
Chromospherically Active Stars. Xxvi. The Double-Lined Late-Type Binary Hd 19485 = Wz Arietis, Francis C. Fekel, Charles Thomas Bolton
Chromospherically Active Stars. Xxvi. The Double-Lined Late-Type Binary Hd 19485 = Wz Arietis, Francis C. Fekel, Charles Thomas Bolton
Information Systems and Engineering Management Research Publications
We have used spectroscopic observations to determine the orbital elements and some basic properties of the double-lined spectroscopic binary HD 19485 = WZ Ari. The orbital period is 6.247854 days, and the orbit is circular. The G5 V primary and K0 V secondary are chromospherically active. One star or possibly both are synchronously rotating. Based on the Hipparcos parallax and the magnitude differences derived in this work, we find that both components are approximately 1 mag above the zero-age main sequence, a result that is inconsistent with the assumption that the components are coeval. We discuss some possible solutions to …
The Spectroscopic And Astrometric Orbits Of Hr 672, Francis C. Fekel, Michael H. Williamson, Dimitri Pourbaix
The Spectroscopic And Astrometric Orbits Of Hr 672, Francis C. Fekel, Michael H. Williamson, Dimitri Pourbaix
Information Systems and Engineering Management Research Publications
From a very extensive set of radial velocities obtained at Fairborn Observatory we have computed a new spectroscopic orbit for HR 672. This binary has an orbital period of 93.290 days and an eccentricity of 0.5249. The greatly improved orbital elements have been incorporated into a new astrometric orbit, which has an inclination of 110°, from Hipparcos data. The primary is a slowly rotating early G star that is situated nearly 1 mag above the main sequence and is likely pseudosynchronously rotating. It has an iron abundance that is greater than that of the Sun. Lines of the secondary were …
Butterfly Diagram And Activity Cycles In Hr 1099, Svetlana Berdyugina, Gregory W. Henry
Butterfly Diagram And Activity Cycles In Hr 1099, Svetlana Berdyugina, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We analyze photometric data of the active RS CVn-type star HR 1099 for the years 1975-2006 with an inversion technique and reveal the nature of two activity cycles of 15-16 yr and 5.3 ± 0.1 yr duration. The 16 yr cycle is related to variations of the total spot area and is coupled with the differential rotation, while the 5.3 yr cycle is caused by the symmetric redistribution of the spotted area between the opposite stellar hemispheres (flip-flop cycle). We recover long-lived active regions comprising two active longitudes that migrate in the orbital reference frame with a variable rate because …