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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
A Transiting "51 Peg-Like" Planet, Gregory W. Henry, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt
A Transiting "51 Peg-Like" Planet, Gregory W. Henry, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt
Information Systems and Engineering Management Research Publications
Doppler measurements from Keck exhibit a sinusoidal periodicity in the velocities of the G0 dwarf HD 209458, having a semiamplitude of 81 m s-1 and a period of 3.5239 days, which is indicative of a "51 Peg-like" planet with a minimum mass (M sin i) of 0.62 MJup and a semimajor axis of 0.046 AU. Follow-up photometry reveals a drop of 0.017 mag at the predicted time (within the errors) of transit by the companion based on the velocities. This is the first extrasolar planet observed to transit its star. The radius of the planet derived …
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
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 …
Techniques For Automated High‐Precision Photometry Of Sun‐Like Stars, Gregory W. Henry
Techniques For Automated High‐Precision Photometry Of Sun‐Like Stars, Gregory W. Henry
Information Systems and Engineering Management Research Publications
Tennessee State University operates several Automatic Photoelectric Telescopes (APTs) located at Fairborn Observatory in the Patagonia Mountains of southern Arizona. The APTs are dedicated to photometric monitoring programs that would be difficult and expensive to accomplish without the advantages provided by automation. I describe the operation of two of the telescopes (0.75 and 0.80 m APTs) and the quality‐control techniques that result in their routine acquisition of single‐star differential photometry with a precision of 0.001 mag for single observations and 0.0001–0.0002 mag for seasonal means. I show that a primary obstacle to photometry at this level of precision is intrinsic …
Orbital Elements And Physical Parameters Of Ten Chromospherically Active Binary Stars, Francis C. Fekel, Klaus G. Strassmeier, Michael Weber, A. Washuettl
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
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 …
The Visual Orbit Of Ι Pegasi, Andrew F. Boden, Christopher D. Koresko, Gerard T. Van Belle, Mark M. Colavita, Philip J. Dumont, Joseph Gubler, Shrinivas R. Kulkarni, Benjamin F. Lane, Dasia Mobley, Michael Shao, James K. Wallace, The Pti Collaboration, Gregory W. Henry
The Visual Orbit Of Ι Pegasi, Andrew F. Boden, Christopher D. Koresko, Gerard T. Van Belle, Mark M. Colavita, Philip J. Dumont, Joseph Gubler, Shrinivas R. Kulkarni, Benjamin F. Lane, Dasia Mobley, Michael Shao, James K. Wallace, The Pti Collaboration, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We have determined the visual orbit for the spectroscopic binary ι Pegasi with interferometric visibility data obtained by the Palomar Testbed Interferometer in 1997. ι Peg is a double-lined binary system whose minimum masses and spectral typing suggests the possibility of eclipses. Our orbital and component diameter determinations do not favor the eclipse hypothesis: the limb-to-limb separation of the two components is 0.151±0.069 mas at conjunction. Our conclusion that the ι Peg system does not eclipse is supported by high-precision photometric observations. The physical parameters implied by our visual orbit and the spectroscopic orbit of Fekel & Tomkin are in …
Hd 62454 And Hd 68192: Two New Γ Doradus Variables, Anthony B. Kaye, Gregory W. Henry, Francis C. Fekel, Richard O. Gray, Eloy Rodríguez, Susana Martín, Douglas R. Gies, William G. Bagnuolo, Douglas S. Hall
Hd 62454 And Hd 68192: Two New Γ Doradus Variables, Anthony B. Kaye, Gregory W. Henry, Francis C. Fekel, Richard O. Gray, Eloy Rodríguez, Susana Martín, Douglas R. Gies, William G. Bagnuolo, Douglas S. Hall
Information Systems and Engineering Management Research Publications
We present multilongitude, multicolor photometry and simultaneous high-resolution, high signal-to-noise spectroscopy of the newly discovered γ Doradus variables HD 62454 and HD 68192. From combined Johnson and Strömgren data, we are able to identify five independent periods in HD 62454 and two stable periods in HD 68192. The data presented are sufficient to rule out all physically meaningful types of variations, with the one exception of the high-order, low-degree, nonradial gravity-mode pulsations that are believed to be at work in γ Doradus stars. We also find that HD 62454 is a double-lined spectroscopic binary and we present an orbital solution.