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Full-Text Articles in Physical Sciences and Mathematics
Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson
Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson
Information Systems and Engineering Management Research Publications
We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate γ Doradus (γ Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new γ Dor variables. All exhibit sinusoidal variability with amplitudes between 6 and 65 mmag in Johnson B and periods from 0.28 to 1.13 days. All lie in the same region of the H-R diagram as our previously confirmed γ Dor stars. Of the nine systems, one is a single-lined spectroscopic binary (SB1), two are double-lined spectroscopic binaries (SB2), and …
Establishing Α Oph As A Prototype Rotator: Precision Orbit With New Keck, Chara, And Rv Observations, Tyler Gardner, John D. Monnier, Francis C. Fekel, Michael H. Williamson, Fabien Baron, Sasha Hinkley, Michael Ireland, Adam L. Kraus, Stefan Kraus, Rachael M. Roettenbacher, Gail Schaefer, Judit Sturmann, Laszlo Sturmann, Theo A. Ten Brummelaar
Establishing Α Oph As A Prototype Rotator: Precision Orbit With New Keck, Chara, And Rv Observations, Tyler Gardner, John D. Monnier, Francis C. Fekel, Michael H. Williamson, Fabien Baron, Sasha Hinkley, Michael Ireland, Adam L. Kraus, Stefan Kraus, Rachael M. Roettenbacher, Gail Schaefer, Judit Sturmann, Laszlo Sturmann, Theo A. Ten Brummelaar
Information Systems and Engineering Management Research Publications
Alpha Ophiuchi (Rasalhague) is a nearby rapidly rotating A5IV star that has been imaged by infrared interferometry. α Oph is also part of a known binary system, with a companion semimajor axis of ∼430 mas and a high eccentricity of 0.92. The binary companion provides the unique opportunity to measure the dynamical mass to compare with the results of rapid rotator evolution models. The lack of data near periastron passage limited the precision of mass measurements in previous work. We add new interferometric data from the MIRC combiner at the CHARA Array as well as new Keck adaptive optics imaging …
Observations With The Differential Speckle Survey Instrument. X. Preliminary Orbits Of K-Dwarf Binaries And Other Stars, Elliott P. Horch, Kyle G. Broderick, Dana I. Casetti-Dinescu, Todd J. Henry, Francis C. Fekel, Matthew W. Muterspaugh, Daryl W. Willmarth, Jennifer G. Winters, Gerard T. Van Belle, Catherine A. Clark, Mark E. Everett
Observations With The Differential Speckle Survey Instrument. X. Preliminary Orbits Of K-Dwarf Binaries And Other Stars, Elliott P. Horch, Kyle G. Broderick, Dana I. Casetti-Dinescu, Todd J. Henry, Francis C. Fekel, Matthew W. Muterspaugh, Daryl W. Willmarth, Jennifer G. Winters, Gerard T. Van Belle, Catherine A. Clark, Mark E. Everett
Information Systems and Engineering Management Research Publications
This paper details speckle observations of binary stars taken at the Lowell Discovery Telescope, the WIYN telescope, and the Gemini telescopes between 2016 January and 2019 September. The observations taken at Gemini and Lowell were done with the Differential Speckle Survey Instrument (DSSI), and those done at WIYN were taken with the successor instrument to DSSI at that site, the NN-EXPLORE Exoplanet Star and Speckle Imager (NESSI). In total, we present 378 observations of 178 systems, and we show that the uncertainty in the measurement precision for the combined data set is ∼2 mas in separation, ∼1°–2° in position angle …
Visual Orbits Of Spectroscopic Binaries With The Chara Array. Iii. Hd 8374 And Hd 24546, Kathryn V. Lester, Francis C. Fekel, Matthew W. Muterspaugh, Douglas R. Gies, Gail Schaefer, Chris D. Farrington, Zhao Guo, Rachel A. Matson, John D. Monnier, Theo A. Ten Brummelaar, Judit Sturmann, Samuel A. Weiss
Visual Orbits Of Spectroscopic Binaries With The Chara Array. Iii. Hd 8374 And Hd 24546, Kathryn V. Lester, Francis C. Fekel, Matthew W. Muterspaugh, Douglas R. Gies, Gail Schaefer, Chris D. Farrington, Zhao Guo, Rachel A. Matson, John D. Monnier, Theo A. Ten Brummelaar, Judit Sturmann, Samuel A. Weiss
Information Systems and Engineering Management Research Publications
We present the visual orbits of two long-period spectroscopic binary stars, HD 8374 and HD 24546, using interferometric observations acquired with the CHARA Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5 m and Fairborn 2.0 m telescopes. By combining the visual and spectroscopic observations, we solve for the full, three-dimensional orbits and determine the stellar masses and distances to within 3% uncertainty. We then estimate the effective temperature and radius of each component star through Doppler tomography and spectral energy distribution analyses, in order to compare the observed stellar …
Kr Persei, A Mid-F Eclipsing Binary With A One-Day Period, James R. Sowell, Emily Hollingworth, Francis C. Fekel, Matthew W. Muterspaugh, Horace Dale, Alexander D. Savello, Jeffrey L. Coughlin, Richard M. Williamon
Kr Persei, A Mid-F Eclipsing Binary With A One-Day Period, James R. Sowell, Emily Hollingworth, Francis C. Fekel, Matthew W. Muterspaugh, Horace Dale, Alexander D. Savello, Jeffrey L. Coughlin, Richard M. Williamon
Information Systems and Engineering Management Research Publications
KR Per is a partially eclipsing binary with an orbital period of 0.9960798 days, very close to one sidereal day, making it difficult to obtain extensive phase coverage in a reasonable amount of time. We used the Wilson–Devinney program to determine its orbital elements and stellar absolute dimensions from recently acquired radial velocities and differential BVRI observations that were supplemented with previous differential UBV measurements and published times of minima. The two components are each F5 V stars with masses of and . The radii are and . The orbital period of the eclipsing system is variable and more times …
Observations Of Binary Stars With The Differential Speckle Survey Instrument. Ix. Observations Of Known And Suspected Binaries, And A Partial Survey Of Be Stars, Elliott P. Horch, Gerard T. Van Belle, James W. Davidson Jr., Daryl W. Willmarth, Francis C. Fekel, Matthew W. Muterspaugh, Dana I. Casetti-Dinescu, Frederick W. Hahne, Nicole M. Granucci, Catherine A. Clark, Jennifer G. Winters, Justin D. Rupert, Samuel A. Weiss, Nicole M. Colton, Daniel A. Nusdeo, Todd J. Henry
Observations Of Binary Stars With The Differential Speckle Survey Instrument. Ix. Observations Of Known And Suspected Binaries, And A Partial Survey Of Be Stars, Elliott P. Horch, Gerard T. Van Belle, James W. Davidson Jr., Daryl W. Willmarth, Francis C. Fekel, Matthew W. Muterspaugh, Dana I. Casetti-Dinescu, Frederick W. Hahne, Nicole M. Granucci, Catherine A. Clark, Jennifer G. Winters, Justin D. Rupert, Samuel A. Weiss, Nicole M. Colton, Daniel A. Nusdeo, Todd J. Henry
Information Systems and Engineering Management Research Publications
We report 370 measures of 170 components of binary and multiple-star systems, obtained from speckle imaging observations made with the Differential Speckle Survey Instrument at Lowell Observatory's Discovery Channel Telescope in 2015 through 2017. Of the systems studied, 147 are binary stars, 10 are seen as triple systems, and 1 quadruple system is measured. Seventy-six high-quality nondetections and 15 newly resolved components are presented in our observations. The uncertainty in relative astrometry appears to be similar to our previous work at Lowell, namely, linear measurement uncertainties of approximately 2 mas, and the relative photometry appears to be uncertain at the …
Hd 126516: A Triple System Containing A Short-Period Eclipsing Binary, Francis C. Fekel, Gregory W. Henry, James R. Sowell
Hd 126516: A Triple System Containing A Short-Period Eclipsing Binary, Francis C. Fekel, Gregory W. Henry, James R. Sowell
Information Systems and Engineering Management Research Publications
From numerous radial velocities as well as Johnson B and V differential photoelectric photometry, we have determined the orbital elements and other properties of the single-lined triple system HD 126516. This system consists of a narrow-lined F5 V star and an unseen M dwarf companion in a 2.1241 day circular orbit. The small, low-mass secondary produces detectable eclipses of the primary, and that pair has been given the variable star name V349 Vir. Variations of the center-of-mass velocity of this short-period system have an orbital period of 702.7 days or 1.92 yr and an eccentricity of 0.36. The third star …
Chromospherically Active Stars. Xviii. Sorting Out The Variability Of Hd 95559 And Gliese 410=Ds Leonis, Francis C. Fekel, Gregory W. Henry
Chromospherically Active Stars. Xviii. Sorting Out The Variability Of Hd 95559 And Gliese 410=Ds Leonis, Francis C. Fekel, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We have obtained spectroscopy and photometry of HD 95559 and photometry of Gliese 410=DS Leonis. HD 95559 consists of a pair of essentially identical K1 V stars, whose orbital period we refine to 1.52599775+/-0.00000104 days. The system is photometrically variable with a mean period of 1.5264+/-0.0003 days. Despite minimum masses greater than 0.8 Msolar for each component, a search for eclipses proved negative. The lithium abundances of the components of HD 95559 indicate that the system is younger than the Hyades cluster, and its components may even have just arrived on the zero-age main sequence. Gl 410=DS Leo is also …