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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

Information Systems and Engineering Management Research Publications

1999

Stellar activity

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Simultaneous Photometry And Spectroscopy Of The Newly Discovered Γ Doradus Variable Hr 8330=Hd 207223, Anthony B. Kaye, Gregory W. Henry, Francis C. Fekel, Douglas S. Hall Oct 1999

Simultaneous Photometry And Spectroscopy Of The Newly Discovered Γ Doradus Variable Hr 8330=Hd 207223, Anthony B. Kaye, Gregory W. Henry, Francis C. Fekel, Douglas S. Hall

Information Systems and Engineering Management Research Publications

We present BV photometry and simultaneous high-resolution, high signal-to-noise ratio spectroscopy of the newly-discovered γ Doradus variable HR 8330 taken during the 1997 and 1998 observing seasons. We calculate power spectra for the B- and V-band data sets and for the time series defined throughout the observing season at each point across the Fe iiλ4508.289 and the Ti iiλ4501.278 line profiles to search for periodic variability. Period analysis reveals a single, 2.6-d period in both the photometric and the spectroscopic data, with a 237° phase lag between them. Based on the location of HR 8330 in the HR diagram and …


Orbital Elements And Physical Parameters Of Ten Chromospherically Active Binary Stars, Francis C. Fekel, Klaus G. Strassmeier, Michael Weber, A. Washuettl Jun 1999

Orbital Elements And Physical Parameters Of Ten Chromospherically Active Binary Stars, Francis C. Fekel, Klaus G. Strassmeier, Michael Weber, A. Washuettl

Information Systems and Engineering Management Research Publications

Orbital elements have been determined for 10 chromospherically active binaries from a combination of new velocities and velocities in the literature. First orbits for three binaries, HD 33363, HD 152178, and HD 208472, are presented, as well as updated orbits for seven other binaries. Two of the latter systems, LN Peg and HD 106225 were discovered to be triple, and both short- and long-period orbits have been computed for each. Fundamental properties have been determined for the chromopherically active primary in each system.


Evolved, Single, Slowly Rotating . . . But Magnetically Active The G8-Giant Hr 1362 = Ek Eridani Revisited, Klaus G. Strassmeier, Kazimierz Stępień, Gregory W. Henry, Douglas S. Hall Jan 1999

Evolved, Single, Slowly Rotating . . . But Magnetically Active The G8-Giant Hr 1362 = Ek Eridani Revisited, Klaus G. Strassmeier, Kazimierz Stępień, Gregory W. Henry, Douglas S. Hall

Information Systems and Engineering Management Research Publications

We rediscuss the unusual case of the slowly rotating late-type giant HR 1362, which exhibits a very unusual high level of magnetic activity. New BVRI photometry from two robotic telescopes from 1991 through 1998 together with previously published photometric data gives a very precise photometric period of 306.9±0.4 days. With the aid of high-resolution (R=120,000) optical spectra and the Hipparcos parallax we redetermine the absolute parameters of HR 1362 and find it to be a single G8IV-III star of 14 L and a mass of 1.85 M with Teff=5125 K, log g=3.25, and solar abundances. Lithium is not significantly different …