Physical Sciences and Mathematics Commons^™

Absolute Dimensions Of The Early F-Type Eclipsing Binary V506 Ophiuchi, Guillermo Torres, Claud H. Sandberg Lacy, Francis C. Fekel, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We report extensive differential V-band photometry and high-resolution spectroscopic observations of the early F-type, 1.06-day detached eclipsing binary V506 Oph. The observations, along with times of minimum light from the literature, are used to derive a very precise ephemeris and the physical properties for the components, with the absolute masses and radii being determined to 0.7% or better. The masses are 1.4153 ± 0.0100 M☉ and 1.4023 ± 0.0094 M☉ for the primary and secondary, the radii are 1.725 ± 0.010 R☉ and 1.692 ± 0.012 R☉, and the effective temperatures are 6840 ± 150 K and 6780 ± 110 …

The Quadruple-Lined, Doubly Eclipsing System V482 Persei, Guillermo Torres, Claud H. Sandberg Lacy, Francis C. Fekel, Marek Wolf, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We report spectroscopic and differential photometric observations of the A-type system V482 Per, which reveal it to be a rare hierarchical quadruple system containing two eclipsing binaries. One binary has the previously known orbital period of 2.4 days and a circular orbit, and the other a period of 6 days, a slightly eccentric orbit (e = 0.11), and shallow eclipses only 2.3% deep. The two binaries revolve around their common center of mass in a highly elongated orbit (e = 0.85) with a period of 16.67 yr. Radial velocities are measured for all components from our quadruple-lined spectra and are …

Orbital Solutions And Absolute Elements Of The Massive Algol Binary Et Tauri, Richard M. Williamon, Horace Dale, Charles L. Evavold, Alexander Langoussis, Francis C. Fekel, Matthew W. Muterspaugh, Stephen Williams, Kate Napier, James R. Sowell

Information Systems and Engineering Management Research Publications

We acquired differential UBV photoelectric photometry and radial velocities of the relatively bright, understudied, massive Algol binary ET Tau and utilized the Wilson-Devinney (WD) analysis program to obtain a simultaneous solution of these observations. To improve the orbital ephemeris, the V measurements from the ASAS program were also analyzed. Because of the very rapid rotation of the significantly more massive and hotter component (B2/3 spectral class), only radial velocities of the secondary component, which has a ∼B7 spectral class, could be measured. We derive masses of ${M}_{1}=14.34\pm 0.28\,{M}_{\odot }$ and ${M}_{2}=6.339\pm 0.117\,{M}_{\odot }$ and equal-volume radii of ${R}_{1}=6.356\pm 0.056\,{R}_{\odot }$ …

Absolute Properties Of The Pre-Main-Sequence Eclipsing Binary Star Np Persei, Claud H. Sandberg Lacy, Francis C. Fekel, Krešimir Pavlovski, Guillermo Torres, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

NP Per is a well-detached, 2.2 day eclipsing binary whose components are both pre-main-sequence stars that are still contracting toward the main-sequence phase of evolution. We report extensive photometric and spectroscopic observations with which we have determined their properties accurately. Their surface temperatures are quite different: 6420 ± 90 K for the larger F5 primary star and 4540 ± 160 K for the smaller K5e star. Their masses and radii are 1.3207 ± 0.0087 solar masses and 1.372 ± 0.013 solar radii for the primary, and 1.0456 ± 0.0046 solar masses and 1.229 ± 0.013 solar radii for the secondary. …

Absolute Dimensions Of The Metallic-Line Eclipsing Binary V501 Monocerotis, Guillermo Torres, Claud H. Sandberg Lacy, Krešimir Pavlovski, Francis C. Fekel, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We report extensive high-resolution spectroscopic observations and V-band differential photometry of the slightly eccentric 7.02 day detached eclipsing binary V501 Mon (A6m+F0), which we use to determine its absolute dimensions to high precision (0.3% for the masses and 1.8% for the radii, or better). The absolute masses, radii, and temperatures are MA = 1.6455 ± 0.0043 M⊙, RA = 1.888 ± 0.029 R⊙, and ${T}_{{\rm{eff}}}^{{\rm{A}}}$ = 7510 ± 100 K for the primary and MB = 1.4588 ± 0.0025 M⊙, RB = 1.592 ± 0.028 R⊙, and TeffB = 7000 ± 90 K for the secondary. Apsidal motion has been …

Absolute Properties Of The Eclipsing Binary Star Im Persei, Claud H. Sandberg Lacy, Guillermo Torres, Francis C. Fekel, Matthew W. Muterspaugh, John Southworth

Information Systems and Engineering Management Research Publications

IM Per is a detached A7 eccentric eclipsing binary star. We have obtained extensive measurements of the light curve (28,225 differential magnitude observations) and radial velocity curve (81 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.7831 ± 0.0094 and 1.7741 ± 0.0097 solar masses, and radii of 2.409 ± 0.018 and 2.366 ± 0.017 solar radii. The orbital period is 2.25422694(15) days and the eccentricity is 0.0473(26). A faint third component was detected in the analysis of the light curves, and also directly observed in the spectra. …

Absolute Properties Of The Eclipsing Binary Star V501 Herculis, Claud H. Sandberg Lacy, Francis C. Fekel

Information Systems and Engineering Management Research Publications

V501 Her is a well detached G3 eclipsing binary star with a period of 8.597687 days for which we have determined very accurate light and radial-velocity curves using robotic telescopes. Results of these data indicate that the component stars have masses of 1.269 ± 0.004 and 1.211 ± 0.003 solar masses, radii of 2.001 ± 0.003 and 1.511 ± 0.003 solar radii, and temperatures of 5683 ± 100 K and 5720 ± 100 K, respectively. Comparison with the Yonsei–Yale series of evolutionary models results in good agreement at an age of about 5.1 Gyr for a somewhat metal-rich composition. Those …

Absolute Properties Of The Eclipsing Binary Star Ap Andromedae, Claud H. Sandberg Lacy, Guillermo Torres, Francis C. Fekel, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

AP And is a well-detached F5 eclipsing binary star for which only a very limited amount of information was available before this publication. We have obtained very extensive measurements of the light curve (19,097 differential V magnitude observations) and a radial velocity curve (83 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.277 ± 0.004 and 1.251 ± 0.004 M☉, radii of 1.233 ± 0.006 and 1.1953 ± 0.005 R☉, and temperatures of 6565 ± 150 K and 6495 ± 150 K. The distance to the system is …

Absolute Properties Of The Eclipsing Binary Vv Corvi, Francis C. Fekel, Gregory W. Henry, James R. Sowell

Information Systems and Engineering Management Research Publications

We have obtained red-wavelength spectroscopy and Johnson B and V differential photoelectric photometry of the eclipsing binary VV Crv = HR 4821. The system is the secondary of the common proper motion double star ADS 8627, which has a separation of 52. VV Crv has an orbital period of 3.144536 days and a low but non-zero eccentricity of 0.085. With the Wilson–Devinney program we have determined a simultaneous solution of our spectroscopic and photometric observations. Those orbital elements produce masses of M₁ = 1.978 ± 0.010 M_☉ and M₂ = 1.513 ± 0.008 M_☉, and …

Absolute Properties Of The Eclipsing Binary Star V335 Serpentis, Claud H. Sandberg Lacy, Francis C. Fekel, Antonio Claret

Information Systems and Engineering Management Research Publications

V335 Ser is now known to be an eccentric double-lined A1+A3 binary star with fairly deep (0.5 mag) partial eclipses. Previous studies of the system are improved with 7456 differential photometric observations from the URSA WebScope and 5666 from the NFO WebScope, and 67 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope. From dates of minima, the apsidal period is about 880 years. Accurate (better than 2%) masses and radii are determined from analysis of the two new light curves and the radial velocity curve. Theoretical models match the absolute properties of the stars at …

3.6 And 4.5 Μm Phase Curves And Evidence For Non-Equilibrium Chemistry In The Atmosphere Of Extrasolar Planet Hd 189733b, Heather A. Knutson, Nikole K. Lewis, Jonathan J. Fortney, Adam Burrows, Adam P. Showman, Nicolas B. Cowan, Eric Agol, Suzanne Aigrain, David Charbonneau, Drake Deming, Jean-Michel Désert, Gregory W. Henry, Jonathan Langton, Gregory Laughlin

Information Systems and Engineering Management Research Publications

We present new, full-orbit observations of the infrared phase variations of the canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 μm bands using the Spitzer Space Telescope. When combined with previous phase curve observations at 8.0 and 24 μm, these data allow us to characterize the exoplanet's emission spectrum as a function of planetary longitude and to search for local variations in its vertical thermal profile and atmospheric composition. We utilize an improved method for removing the effects of intrapixel sensitivity variations and robustly extracting phase curve signals from these data, and we calculate our best-fit parameters …

Absolute Properties Of The Eclipsing Binary Star Bf Draconis, Claud H. Sandberg Lacy, Guillermo Torres, Francis C. Fekel, Jeffrey A. Sabby, Antonio Claret

Information Systems and Engineering Management Research Publications

BF Dra is now known to be an eccentric double-lined F6+F6 binary star with relatively deep (0.7 mag) partial eclipses. Previous studies of the system are improved with 7494 differential photometric observations from the URSA WebScope and 9700 from the NFO WebScope, 106 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope and the 1 m coudé-feed spectrometer at Kitt Peak National Observatory, and 31 accurate radial velocities from the CfA. Very accurate (better than 0.6%) masses and radii are determined from analysis of the two new light curves and four radial velocity curves. Theoretical models …

Absolute Properties Of The Highly Eccentric, Solar-Type Eclipsing Binary Hd 74057, James R. Sowell, Gregory W. Henry, Francis C. Fekel

Information Systems and Engineering Management Research Publications

We have obtained Strömgren b and y differential photometric observations of the solar-type eclipsing binary HD 74057 plus follow-up high-resolution, red wavelength spectroscopic observations. The system has an orbital period of 31.2198 days, a high eccentricity of 0.47, and is seen almost exactly edge on with an inclination of 89fdg8. The two main-sequence G0 stars are nearly identical in all physical characteristics. We used the Wilson–Devinney program to obtain a simultaneous solution of our photometric and spectroscopic observations. The resulting masses of the components are M1 = 1.138 ± 0.003 M☉ and M2 = 1.131 ± 0.003 M☉, and the …

Absolute Properties Of The Eclipsing Binary Star Hy Virginis, Claud H. Sandberg Lacy, Francis C. Fekel

Information Systems and Engineering Management Research Publications

HY Vir is found to be a double-lined F0m+F5 binary star with relatively shallow (0.3 mag) partial eclipses. Previous studies of the system are improved with 7509 differential photometric observations from the URSA WebScope and 8862 from the NFO WebScope, and 68 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope, and the 1 m coudé-feed spectrometer at Kitt Peak National Observatory. Very accurate (better than 0.5%) masses and radii are determined from analysis of the new light curves and radial velocity curves. Theoretical models match the absolute properties of the stars at an age of …

A Spitzer Transmission Spectrum For The Exoplanet Gj 436b, Evidence For Stellar Variability, And Constraints On Dayside Flux Variations, Heather Knutson, Nikku Madhusudhan, Nicolas B. Cowan, Jessie L. Christiansen, Eric Agol, Drake Deming, Jean-Michel Désert, David Charbonneau, Gregory W. Henry, Derek Homeier, Jonathan Langton, Gregory Laughlin, Sara Seager

Information Systems and Engineering Management Research Publications

In this paper, we describe a uniform analysis of eight transits and eleven secondary eclipses of the extrasolar planet GJ 436b obtained in the 3.6, 4.5, and 8.0 μm bands using the IRAC instrument on the Spitzer Space Telescope between UT 2007 June 29 and UT 2009 February 4. We find that the best-fit transit depths for visits in the same bandpass can vary by as much as 8% of the total (4.7σ significance) from one epoch to the next. Although we cannot entirely rule out residual detector effects or a time-varying, high-altitude cloud layer in the planet's atmosphere as …

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. Vi. Hd 24623 And V923 Scorpii, Francis C. Fekel, Michael H. Williamson, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Using new radial velocities obtained at KPNO and Fairborn Observatory, we have determined improved spectroscopic orbits for two double-lined F-type binaries, HD 24623 and V923 Sco. The orbital periods are 19.66304 and 34.8386 days, respectively, so it is not surprising that their orbits have relatively high eccentricities of nearly 0.5. The orbital dimensions (a1sin i and a2sin i) and minimum masses (m1sin 3i and m2sin 3i) have accuracies of 0.2% or better. Extensive photometry of HD 24623 with the T4 0.75 m automatic photometric telescope at Fairborn Observatory shows no evidence of eclipses. Instead, a very weak reflection effect is …

The Phases Differential Astrometry Data Archive. Ii. Updated Binary Star Orbits And A Long Period Eclipsing Binary, Matthew W. Muterspaugh, William I. Hartkopf, Benjamin F. Lane, Julia O'Connell, Michael Williamson, Shrinivas R. Kulkarni, Maciej Konacki, Bernard F. Burke, Mark M. Colavita, Michael Shao, Sloane J. Wiktorowicz

Information Systems and Engineering Management Research Publications

Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with lower precision single-aperture measurements covering a much longer timespan (from eyepiece measurements, speckle interferometry, and adaptive optics) to determine improved visual orbits for 20 binary stars. In some cases, radial velocity observations exist to constrain the full three-dimensional orbit and determine component masses. The visual orbit of one of these binaries—α Com (HD 114378)—shows that the system is likely to have eclipses, despite its very long period of 26 years. The next eclipse is predicted to be within a week of 2015 January 24.

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. Iv. 66 Andromedae, Hr 6979, And Hr 9059, Francis C. Fekel, Jocelyn Tomkin, Michael H. Williamson

Information Systems and Engineering Management Research Publications

We have determined improved spectroscopic orbits for three double-lined binaries, 66 And (F4 V), HR 6979 (Am), and HR 9059 (F5 IV) using radial velocities from the 2.1 m telescope at McDonald Observatory, the coudé feed telescope at Kitt Peak National Observatory, and 2 m telescope at Fairborn Observatory. The orbital periods range from 11.0 to 14.3 days, and all three systems have eccentric orbits. The new orbital dimensions (a1 sin i and a2 sin i) and minimum masses (m1 sin3 i and m2 sin3 i) have accuracies of 0.2% or better. All six components of the three binary systems …

Mass Transfer Variations In Ux Monocerotis: Eight Years Of Automated Photometric Monitoring, Edward C. Olson, Gregory W. Henry, Paul B. Etzel

Information Systems and Engineering Management Research Publications

We analyze eight years (1999–2007) of automated photometric observations of the active Algol binary UX Monocerotis to search for mass transfer bursts similar to those seen in U Cephei. The largest photometric anomaly is the mean gainer luminosity difference between the stream-impact hemisphere and the opposite hemisphere. We find an updated Wilson–Devinney solution for earlier six-color observations. The UX Mon donor star fills its Roche lobe and the gainer nearly fills its rotational lobe. Instead of isolated bursts of the U Cep type, we found nearly continuous brightness fluctuations likely produced by variable mass transfer. We discuss implications for mass …

Transit Spectrophotometry Of The Exoplanet Hd 189733b I. Searching For Water But Finding Haze With Hst Nicmos, David K. Sing, Jean-Michel Désert, Alain Lecavelier Des Etangs, Gilda E. Ballester, Alfred Vidal-Madjar, Vivien Parmentier, Guillaume Hébrard, Gregory W. Henry

Information Systems and Engineering Management Research Publications

We present Hubble Space Telescope near-infrared transit photometry of the nearby hot-Jupiter HD 189733b. The observations were taken with the NICMOS instrument during five transits, with three transits executed with a narrowband filter at 1.87 m and two performed with a narrowband filter at 1.66 m. Our observing strategy using narrowband filters is insensitive to the usual HST intra-orbit and orbit-to-orbit measurement of systematic errors, allowing us to accurately and robustly measure the near-IR wavelength dependance of the planetary radius. Our measurements fail to reproduce the previously claimed detection of an absorption signature of atmospheric H₂O below …

Multiwavelength Constraints On The Day–Night Circulation Patterns Of Hd 189733b, Heather Knutson, David Charbonneau, Nicolas B. Cowan, Jonathan J. Fortney, Adam P. Showman, Eric Agol, Gregory W. Henry, Mark E. Everett, Lori E. Allen

Information Systems and Engineering Management Research Publications

We present new Spitzer observations of the phase variation of the hot Jupiter HD 189733b in the MIPS 24 μm bandpass, spanning the same part of the planet's orbit as our previous observations in the IRAC 8 μm bandpass (Knutson et al. 2007). We find that the minimum hemisphere-averaged flux from the planet in this bandpass is 76% ± 3% of the maximum flux; this corresponds to minimum and maximum hemisphere-averaged brightness temperatures of 984 ± 48 K and 1220 ±  47 K, respectively. The planet reaches its maximum flux at an orbital phase of 0.396 ± 0.022, corresponding to …

The Chromospherically Active, Triple, Ellipsoidal, And Eclipsing Binary Hd 6286 = Be Piscium: A Laboratory For Binary Evolution, Klaus G. Strassmeier, János Bartus, Francis C. Fekel, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Aims. We present a detailed analysis of the star HD 6286 = BE Psc from 16 years of spectroscopic observations and 18 seasons of photometric ones. The star is an evolved, chromospherically active, eclipsing binary, consisting of a K1 giant plus an F6 dwarf/subgiant in a circular orbit with a period of 35.671 days. A faint, close visual companion of spectral type ≈G0 makes the system triple. The orbital inclination of the eclipsing pair is 818.

Methods. We have obtained simultaneous solutions with our extensive set of radial velocities and light curves that include the star spot variability of …

Hd 71636, A Newly Discovered Eclipsing Binary, Gregory W. Henry, Francis C. Fekel, James R. Sowell, Joel S. Gearhart

Information Systems and Engineering Management Research Publications

Our differential BV photometric observations, acquired with an automated telescope at Fairborn Observatory, show that HD 71636 is an eclipsing binary. From follow-up red-wavelength spectroscopic observations we classify the primary and secondary as an F2 dwarf and an F5 dwarf, respectively. The system has a period of 5.01329 days and a circular orbit. We used the Wilson-Devinney program to simultaneously solve our BV light curves and radial velocities and determined a number of fundamental properties of the system. Comparison with evolutionary tracks indicates that both stars are well ensconced on the main sequence. The age of the system is about …

Hd 131861, A Double-Line Spectroscopic Triple System, Francis C. Fekel, Gregory W. Henry, David J. Barlow, Dimitri Pourbaix

Information Systems and Engineering Management Research Publications

Our red-wavelength spectroscopic observations of HD 131861, a previously known single-line multiple system, span 20 years. Now lines of two components, the short-period F5 V primary and G8 V secondary, have been detected. The inner orbit is circular with a period of 3.5507439 days, while the outer orbit of the system has a period of 1642 days or 4.496 yr and a relatively low eccentricity of 0.10. Analysis of the Hipparcos data produces a well-determined astrometric orbit for the long-period system that has an inclination of 52°. Our photometric observations show shallow primary and secondary eclipses of the short-period pair, …

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. I. Rr Lyncis, 12 Bootis, And Hr 6169, Jocelyn Tomkin, Francis C. Fekel

Information Systems and Engineering Management Research Publications

Radial velocities from the 2.1 m telescope at McDonald Observatory supplemented with radial velocities from the coudé feed telescope at Kitt Peak National Observatory provide new precise orbits for the double-lined spectroscopic binaries RR Lyn (A3/A8/A6), 12 Boo (F8 IV), and HR 6169 (A2 V). We derive orbital dimensions (a1 sin i and a2 sin i) and minimum masses (m1 i and m2 i) with accuracies of 0.06%-0.9%. The three systems, which have V magnitudes of 5.53, 4.82, and 6.42, respectively, are all sufficiently bright that they are easily within the grasp of modern optical interferometers and so afford the …