Astrophysics and Astronomy Commons^™

Thermal Structure Of An Exoplanet Atmosphere From Phase-Resolved Emission Spectroscopy, Kevin B. Stevenson, Jean-Michel Désert, Michael R. Line, Jacob L. Bean, Jonathan J. Fortney, Adam P. Showman, Tiffany Kataria, Laura Kreidberg, Peter R. Mccullough, Gregory W. Henry, David Charbonneau, Adam Burrows, Sara Seager, Nikku Madhusudhan, Michael H. Williamson, Derek Homeier

Information Systems and Engineering Management Research Publications

Exoplanets that orbit close to their host stars are much more highly irradiated than their solar system counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase (“phase-curve observations”) for the highly irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet’s atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure …

Astrometry, Radial Velocity, And Photometry: The Hd 128311 System Remixed With Data From Hst, Het, And Apt, Barbara E. Mcarthur, George Fritz Benedict, Gregory W. Henry, Artie Hatzes, William D. Cochran, Tom E. Harrison, Chris Johns-Krull, Ed Nelan

Information Systems and Engineering Management Research Publications

We have used high-cadence radial velocity measurements from the Hobby–Eberly Telescope with published velocities from the Lick 3 m Shane Telescope, combined with astrometric data from the Hubble Space Telescope (HST) Fine Guidance Sensors to refine the orbital parameters of the HD 128311 system, and determine an inclination of 55fdg95 ± 14fdg55 and true mass of 3.789 $^{+0.924}_{ -0.432}$ MJUP for HD 128311 c. The combined radial velocity data also reveal a short period signal which could indicate a third planet in the system with an Msin i of 0.133 ± 0.005 MJUP or stellar phenomena. Photometry from the T12 …

The Nasa-Uc-Uh Eta-Earth Program. Iv. A Low-Mass Planet Orbiting An M Dwarf 3.6 Pc From Earth, Andrew W. Howard, Geoffrey W. Marcy, Debra A. Fischer, Howard Isaacson, Philip S. Muirhead, Gregory W. Henry, Tabetha S. Boyajian, Kaspar Von Braun, Juliette C. Becker, Jason T. Wright, John Asher Johnson

Information Systems and Engineering Management Research Publications

We report the discovery of a low-mass planet orbiting Gl 15 A based on radial velocities from the Eta-Earth Survey using HIRES at Keck Observatory. Gl 15 Ab is a planet with minimum mass Msin i = 5.35 ± 0.75 M⊕, orbital period P = 11.4433  ±  0.0016 days, and an orbit that is consistent with circular. We characterize the host star using a variety of techniques. Photometric observations at Fairborn Observatory show no evidence for rotational modulation of spots at the orbital period to a limit of ∼0.1 mmag, thus supporting the existence of the planet. We detect a …

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

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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 …

A Precise Water Abundance Measurement For The Hot Jupiter Wasp-43b, Laura Kreidberg, Jacob L. Bean, Jean-Michel Désert, Michael R. Line, Jonathan J. Fortney, Nikku Madhusudhan, Kevin B. Stevenson, Adam P. Showman, David Charbonneau, Peter Mccullough, Sara Seager, Adam Burrows, Gregory W. Henry, Michael H. Williamson, Tiffany Kataria, Derek Homeier

Information Systems and Engineering Management Research Publications

The water abundance in a planetary atmosphere provides a key constraint on the planet's primordial origins because water ice is expected to play an important role in the core accretion model of planet formation. However, the water content of the solar system giant planets is not well known because water is sequestered in clouds deep in their atmospheres. By contrast, short-period exoplanets have such high temperatures that their atmospheres have water in the gas phase, making it possible to measure the water abundance for these objects. We present a precise determination of the water abundance in the atmosphere of the …

Warm Ice Giant Gj 3470b – Ii. Revised Planetary And Stellar Parameters From Optical To Near-Infrared Transit Photometry, Lauren I. Biddle, Kyle A. Pearson, Ian J. M. Crossfield, Benjamin J. Fulton, Simona Ciceri, Jason Eastman, Travis Barman, Andrew W. Mann, Gregory W. Henry, Andrew W. Howard, Michael H. Williamson, Evan Sinukoff, Diana Dragomir, Laura Vican, Luigi Mancini, John Southworth, Adam Greenberg, Jake D. Turner, Robert Thompson, Brian W. Taylor, Stephen E. Levine, Matthew W. Webber

Information Systems and Engineering Management Research Publications

It is important to explore the diversity of characteristics of low-mass, low-density planets to understand the nature and evolution of this class of planets. We present a homogeneous analysis of 12 new and 9 previously published broad-band photometric observations of the Uranus-sized extrasolar planet GJ 3470b, which belongs to the growing sample of sub-Jovian bodies orbiting M dwarfs. The consistency of our analysis explains some of the discrepancies between previously published results and provides updated constraints on the planetary parameters. Our data are also consistent with previous transit observations of this system. The physical properties of the transiting system can …

The Lick–Carnegie Exoplanet Survey: Gliese 687 B—A Neptune-Mass Planet Orbiting A Nearby Red Dwarf, Jennifer Burt, Steve Vogt, R. Paul Butler, Russell Hanson, Stefano Meschiari, Eugenio J. Rivera, Gregory W. Henry, Gregory Laughlin

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Precision radial velocities from the Automated Planet Finder (APF) and Keck/HIRES reveal an Msin (i) = 18 ± 2 M⊕ planet orbiting the nearby M3V star GJ 687. This planet has an orbital period P = 38.14 days and a low orbital eccentricity. Our Strömgren b and y photometry of the host star suggests a stellar rotation signature with a period of P = 60 days. The star is somewhat chromospherically active, with a spot filling factor estimated to be several percent. The rotationally induced 60 day signal, however, is well separated from the period of the radial velocity variations, …

Long-Term Monitoring Of Hα Emission Strength And Photometric V Magnitude Of Γ Cas, E. Pollmann, W. Vollmann, Gregory W. Henry

Information Systems and Engineering Management Research Publications

No abstract provided.

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 …

A Four-Planet System Orbiting The K0v Star Hd 141399, Steve Vogt, R. Paul Butler, Eugenio J. Rivera, Robert I. Kibrick, Jennifer Burt, Russell Hanson, Stefano Meschiari, Gregory W. Henry, Gregory Laughlin

Information Systems and Engineering Management Research Publications

We present precision radial velocity (RV) data sets from Keck-HIRES and from Lick Observatory's new Automated Planet Finder Telescope and Levy Spectrometer on Mt. Hamilton that reveal a multiple-planet system orbiting the nearby, slightly evolved, K-type star HD 141399. Our 91 observations over 10.5 yr suggest the presence of four planets with orbital periods of 94.35, 202.08, 1070.35, and 3717.35 days and minimum masses of 0.46, 1.36, 1.22, and 0.69 MJ, respectively. The orbital eccentricities of the three inner planets are small, and the phase curves are well sampled. The inner two planets lie just outside the 2:1 resonance, suggesting …

Spot Activity Of The Rs Canum Venaticorum Star Σ Geminorum, Perttu Kajatkari, Thomas Hackman, Lauri Jetsu, Jyri J. Lehtinen, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Aims. We model the photometry of RS CVn star σ Geminorum to obtain new information on the changes of the surface starspot distribution, that is, activity cycles, differential rotation, and active longitudes.

Methods. We used the previously published continuous period search (CPS) method to analyse V-band differential photometry obtained between the years 1987 and 2010 with the T3 0.4 m Automated Telescope at the Fairborn Observatory. The CPS method divides data into short subsets and then models the light-curves with Fourier-models of variable orders and provides estimates of the mean magnitude, amplitude, period, and light-curve minima. These light-curve parameters …

The Orbits Of The Triple-Star System 1 Geminorum From Phases Differential Astrometry And Spectroscopy, Benjamin F. Lane, Matthew W. Muterspaugh, Roger F. Griffin, Colin D. Scarfe, Francis C. Fekel, Michael H. Williamson, Joel A. Eaton, Michael Shao, Mark M. Colavita, Maciej Konacki

Information Systems and Engineering Management Research Publications

We have used precise differential astrometry from the Palomar High-precision Astrometric Search for Exoplanet Systems project and radial-velocity measurements covering a time span of 40 yr to determine the orbital parameters of the 1 Geminorum triple system. We present the first detection of the spectral lines of the third component of the system, together with precise mass (0.5%) and distance (0.15%) determinations for this system. In addition, our astrometry allows us to make the first determination of the mutual inclination of the orbits.

Extensive Study Of Hd 25558, A Long-Period Double-Lined Binary With Two Spb Components, Á. Sódor, Peter De Cat, David J. Wright, Coralie Neiner, Maryline Briquet, Patricia Lampens, Robert J. Dukes, Gregory W. Henry, Michael H. Williamson, Emily Brunsden, Karen R. Pollard, Peter L. Cottrell, Florian Maisonneuve, Pam M. Kilmartin, Jaymie Matthews, Thomas Kallinger, Paul G. Beck, Eiji Kambe, Chris A. Engelbrecht, Robert J. Czanik, Stephenson Yang, Osamu Hashimoto, Satoshi Honda, Jian-Ning Fu, Barbara Castanheira, Holger Lehmann, Zsófia Bognár, Natalie Behara, Simone Scaringi, Hans Van Winckel, Jonathan Menu, Alex Lobel, P. Mathias, Sophie Saesen, Maja Vučković, The Mimes Collaboration

Information Systems and Engineering Management Research Publications

We carried out an extensive observational study of the Slowly Pulsating B (SPB) star, HD 25558. The ≈2000 spectra obtained at different observatories, the ground-based and MOST satellite light curves revealed that this object is a double-lined spectroscopic binary with an orbital period of about nine years. The observations do not allow the inference of an orbital solution. We determined the physical parameters of the components, and found that both lie within the SPB instability strip. Accordingly, both show line-profile variations due to stellar pulsations. 11 independent frequencies were identified in the data. All the frequencies were attributed to one …

Orbital Solutions And Absolute Elements Of The Short-Period Eclipsing Binary Es Librae, Nicole E. Cabrera, James R. Sowell, Richard M. Williamon, Thomas F. Collins, Francis C. Fekel, Michael H. Williamson, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We have obtained new differential UBV photoelectric photometry and radial velocities of both components of the short-period eclipsing binary ES Lib. The system has a circular orbit with a period of 0.883040928 days and is seen at an inclination of 70.1°. With the Wilson-Devinney analysis program, we obtained a simultaneous solution of our photometric and spectroscopic observations that resulted in masses of M1 = 2.30 ± 0.03 M⊙ and M2 = 0.97 ± 0.01 M⊙ and the equal-volume radii of R1 = 2.69 ± 0.02 R⊙ and R2 = 1.83 ± 0.01 R⊙ for the primary and secondary, respectively. The …

Multiperiodicity, Modulations And Flip-Flops In Variable Star Light Curves Ii. Analysis Of Ii Pegasus Photometry During 1979–2010, Marjaana Lindborg, Maarit J. Mantere, Nigul Olspert, Jaan Pelt, Thomas Hackman, Gregory W. Henry, Lauri Jetsu, Klaus G. Strassmeier

Information Systems and Engineering Management Research Publications

Aims. According to previously published Doppler images of the magnetically active primary giant component of the RS CVn binary II Peg, the surface of the star was dominated by one single active longitude that was clearly drifting in the rotational frame of the binary system during 1994-2002; later imaging for 2004–2010, however, showed decreased and chaotic spot activity, with no signs of the drift pattern. Here we set out to investigate from a more extensive photometric dataset whether this drift is a persistent phenomenon, in which case it could be caused either by an azimuthal dynamo wave or be an …

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 …

Hubble Space Telescope Hot Jupiter Transmission Spectral Survey: A Detection Of Na And Strong Optical Absorption In Hat-P-1b, Nikolay Nikolov, David K. Sing, Frederic Pont, Adam S. Burrows, Jonathan J. Fortney, Gilda E. Ballester, Thomas M. Evans, Catherine M. Huitson, Hannah R. Wakeford, Paul A. Wilson, Suzanne Aigrain, Drake Deming, Neale P. Gibson, Gregory W. Henry, Heather Knutson, Alain Lecavelier Des Etangs, Adam P. Showman, Alfred Vidal-Madjar, Kevin J. Zahnle

Information Systems and Engineering Management Research Publications

We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on Hubble Space Telescope observations, covering the spectral regime from 0.29 to 1.027 μm with Space Telescope Imaging Spectrograph (STIS), which is coupled with a recent Wide Field Camera 3 (WFC3) transit (1.087 to 1.687 μm). We derive refined physical parameters of the HAT-P-1 system, including an improved orbital ephemeris. The transmission spectrum shows a strong absorption signature shortward of 0.55 μm, with a strong blueward slope into the near-ultraviolet. We detect atmospheric sodium absorption at a 3.3σ significance level, but find no evidence for the …

Hst Hot-Jupiter Transmission Spectral Survey: Evidence For Aerosols And Lack Of Tio In The Atmosphere Of Wasp-12b, David K. Sing, Alain Lecavelier Des Etangs, Jonathan J. Fortney, Adam Burrows, Frederic Pont, Hannah R. Wakeford, Gilda E. Ballester, Nikolay Nikolov, Gregory W. Henry, Suzanne Aigrain, Drake Deming, Thomas M. Evans, Neale P. Gibson, Catherine M. Huitson, Heather Knutson, Adam P. Showman, Alfred Vidal-Madjar, Paul A. Wilson, Michael H. Williamson, Kevin J. Zahnle

Information Systems and Engineering Management Research Publications

We present Hubble Space Telescope (HST) optical transmission spectra of the transiting hot-Jupiter WASP-12b, taken with the Space Telescope Imaging Spectrograph instrument. The resulting spectra cover the range 2900–10 300 Å which we combined with archival Wide Field Camera 3 spectra and Spitzer photometry to cover the full optical to infrared wavelength regions. With high spatial resolution, we are able to resolve WASP-12A's stellar companion in both our images and spectra, revealing that the companion is in fact a close binary M0V pair, with the three stars forming a triple-star configuration. We derive refined physical parameters of the WASP-12 system, …

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. Viii. Hr 1528, Hr 6993, 2 Sagittae, And 18 Vulpeculae, Francis C. Fekel, Jocelyn Tomkin, Michael H. Williamson

Information Systems and Engineering Management Research Publications

Improved orbital elements for four A-star double-lined spectroscopic binaries have been determined with numerous new radial velocities. Three of the four systems, HR 1528, 2 Sge, and 18 Vul, have moderately short orbital periods of 7.05, 7.39, and 9.31 days, respectively, and also have circular or nearly circular orbits. Only HR 6993 with a period of 14.68 days has a significantly eccentric orbit. The close visual companion of 2 Sge has been detected spectroscopically, and its velocity measured. The orbital dimensions (a1 sin i and a2 sin i) and minimum masses (m1 sin3 i and m2 sin3 i) of the …

Hst Hot Jupiter Transmission Spectral Survey: Detection Of Water In Hat-P-1b From Wfc3 Near-Ir Spatial Scan Observations, Hannah R. Wakeford, David K. Sing, Drake Deming, Neale P. Gibson, Jonathan J. Fortney, Adam Burrows, Gilda E. Ballester, Nikolay Nikolov, Suzanne Aigrain, Gregory W. Henry, Heather Knutson, Alain Lecavelier Des Etangs, Frederic Pont, Adam P. Showman, Alfred Vidal-Madjar, Kevin J. Zahnle

Information Systems and Engineering Management Research Publications

We present Hubble Space Telescope near-infrared transmission spectroscopy of the transiting hot-Jupiter HAT-P-1b. We observed one transit with Wide Field Camera 3 using the G141 low-resolution grism to cover the wavelength range 1.087–1.678 μm. These time series observations were taken with the newly available spatial-scan mode that increases the duty cycle by nearly a factor of 2, thus improving the resulting photometric precision of the data. We measure a planet-to-star radius ratio of Rp/R* = 0.117 09 ± 0.000 38 in the white light curve with the centre of transit occurring at 245 6114.345 ± 0.000 133 (JD). We achieve …

Astrometric Mass Ratios For Three Spectroscopic Binaries, Johannes Sahlmann, Francis C. Fekel

Information Systems and Engineering Management Research Publications

The orbits of five single-lined spectroscopic binaries have recently been determined. We now use astrometric measurements that were collected with the HIPPARCOS satellite to constrain the systems’ mass ratios and secondary masses. The barycentric astrometric orbits of three binary systems, HD 140667, HD 158222, and HD 217924, are fully determined and precise estimates of their mass ratios are obtained. Follow-up of these systems with infrared spectroscopy could yield model-independent dynamical masses for all components.

An Hst Optical-To-Near-Ir Transmission Spectrum Of The Hot Jupiter Wasp-19b: Detection Of Atmospheric Water And Likely Absence Of Tio, Catherine M. Huitson, David K. Sing, Frederic Pont, Jonathan J. Fortney, Adam Burrows, Paul A. Wilson, Gilda E. Ballester, Nikolay Nikolov, Neale P. Gibson, Drake Deming, Suzanne Aigrain, Thomas M. Evans, Gregory W. Henry, Alain Lecavelier Des Etangs, Adam P. Showman, Alfred Vidal-Madjar, Kevin J. Zahnle

Information Systems and Engineering Management Research Publications

We measure the transmission spectrum of WASP-19b from three transits using low-resolution optical spectroscopy from the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS). The STIS spectra cover a wavelength range of 0.29–1.03 μm, with resolving power R = 500. The optical data are combined with archival near-infrared data from the HST Wide Field Camera 3 (WFC3) G141 grism, covering the wavelength range from 1.087 to 1.687 μm, with resolving power R = 130. We reach signal-to-noise levels between 3000 and 11 000 in 0.1 μm bins when measuring the transmission spectra from 0.53–1.687 μm. WASP-19 is known to …

Infrared Spectroscopy Of Symbiotic Stars. Ix. D-Type Symbiotic Novae, Kenneth H. Hinkle, Francis C. Fekel, Richard R. Joyce, Peter R. Wood

Information Systems and Engineering Management Research Publications

Time-series spectra of the near-infrared 1.6 μm region have been obtained for five of the six known D-type symbiotic novae. The spectra map the pulsation kinematics of the Mira component in the Mira–white dwarf binary system and provide the center-of-mass velocity for the Mira. No orbital motion is detected in agreement with previous estimates of orbital periods ≳100 yr and semimajor axes ∼50 AU. The 1–5 μm spectra of the Miras show line weakening during dust obscuration events. This results from scattering and continuum emission by 1000 K dust. In the heavily obscured HM Sge system the 4.6 μm CO …

The Prevalence Of Dust On The Exoplanet Hd 189733b From Hubble And Spitzer Observations, Frederic Pont, David K. Sing, Neale P. Gibson, Suzanne Aigrain, Gregory W. Henry, Nawal Husnoo

Information Systems and Engineering Management Research Publications

The hot Jupiter HD 189733b is the most extensively observed exoplanet. Its atmosphere has been detected and characterized in transmission and eclipse spectroscopy, and its phase curve measured at several wavelengths. This paper brings together the results of our campaign to obtain the complete transmission spectrum of the atmosphere of this planet from UV to infrared with the Hubble Space Telescope, using the STIS, ACS and WFC3 instruments. We provide a new tabulation of the transmission spectrum across the entire visible and infrared range. The radius ratio in each wavelength band was re-derived, where necessary, to ensure a consistent treatment …

Host Star Properties And Transit Exclusion For The Hd 38529 Planetary System, Gregory W. Henry, Stephen R. Kane, Sharon X. Wang, Jason T. Wright, Tabetha S. Boyajian, Kaspar Von Braun, David R. Ciardi, Diana Dragomir, Chris D. Farrington, Debra A. Fischer, Natalie R. Hinkel, Andrew W. Howard, Eric Jensen, Gregory Laughlin, Suvrath Mahadevan, Genady Pilyavsky

Information Systems and Engineering Management Research Publications

The transit signature of exoplanets provides an avenue through which characterization of exoplanetary properties may be undertaken, such as studies of mean density, structure, and atmospheric composition. The Transit Ephemeris Refinement and Monitoring Survey is a program to expand the catalog of transiting planets around bright host stars by refining the orbits of known planets discovered with the radial velocity technique. Here we present results for the HD 38529 system. We determine fundamental properties of the host star through direct interferometric measurements of the radius and through spectroscopic analysis. We provide new radial velocity measurements that are used to improve …

Using Photometry To Probe The Circumstellar Environment Of Δ Scorpii, Carol E. Jones, Paul A. Wiegert, Christopher Tycner, Gregory W. Henry, Richard P. Cyr, Robbie J. Halonen, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We acquired Johnson BV photometry of the binary Be disk system δ Scorpii during its 2009, 2010, 2011, and 2012 observing seasons and used it to probe the innermost regions of the disk. We found that several disk building events have occurred during this time, resulting in an overall brightening in the V band and reddening of the system. In addition to these long-term trends, we found cyclical variability in each observing season on timescales between 60 and 100 days. We were able to reproduce the changes in the magnitude and color of δ Sco using our theoretical models and …

The Spectroscopic Orbits Of Five Solar-Type, Single-Lined Binaries, Francis C. Fekel, Samira Rajabi, Matthew W. Muterspaugh, Michael H. Williamson

Information Systems and Engineering Management Research Publications

We have determined spectroscopic orbits for five single-lined spectroscopic binaries, HD 100167, HD 135991, HD 140667, HD 158222, HD 217924. Their periods range from 60.6 to 2403 days and the eccentricities from 0.20 to 0.84. Our spectral classes for the stars confirm that they are of solar type, F9–G5, and all are dwarfs. Their [Fe/H] abundances, determined spectroscopically, are close to the solar value and on average are 0.12 greater than abundances from a photometric calibration. Four of the five stars are rotating faster than their predicted pseudosynchronous rotational velocities.

The Spectroscopic Orbit Of The K-Giant Binary Γ Canis Minoris, Francis C. Fekel, Michael H. Williamson, Michael Weber, Klaus G. Strassmeier, Dimitri Pourbaix

Information Systems and Engineering Management Research Publications

We have determined an improved orbit for the bright, evolved, double lined binary γ Canis Minoris. The system has an orbital period of 389.31 days and an eccentricity of 0.2586. We have revised the secondary to primary mass ratio to 0.987. The spectral types of the primary and secondary are K4 III and K1: III, respectively, and the components have a V magnitude difference of 2.2. Orbital fits to the Hipparcos astrometry are not definitive, but they suggest an orbital inclination of ∼ 66°, which produces masses of 1.88 and 1.85 M⊙ for the components. A comparison with evolutionary tracks …

The Stellar Activity-Rotation Relationship, Nick J. Wright, Jeremy J. Drake, Eric E. Mamajek, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Using a new catalog of 824 solar and late-type stars with measured X-ray luminosities and rotation periods we have studied the relationship between rotation and stellar activity that is believed to be a probe of the underlying stellar dynamo. Using an unbiased subset of the sample we calculate the power law slope of the unsaturated regime of the activity-rotation relationship as LX/Lbol α Roβ, where β = –2.70 ± 0.13. Notably this is inconsistent with the canonical β = –2 slope to a confidence of 5σ are argues for an interface-type dynamo. Super-saturation is observed for the fastest rotators in …

The Discovery Of Hd 37605c And A Dispositive Null Detection Of Transits Of Hd 37605b, Sharon Xuesong Wang, Jason T. Wright, William D. Cochran, Stephen R. Kane, Gregory W. Henry, Matthew J. Payne, Michael Endl, Phillip J. Macqueen, Jeff A. Valenti, Victoria Antoci, Diana Dragomir, Jaymie M. Matthews, Andrew W. Howard, Geoffrey W. Marcy, Howard Isaacson, Eric B. Ford, Suvrath Mahadevan, Kaspar Von Braun

Information Systems and Engineering Management Research Publications

We report the radial velocity discovery of a second planetary mass companion to the K0 V star HD 37605, which was already known to host an eccentric, P ∼ 55 days Jovian planet, HD 37605b. This second planet, HD 37605c, has a period of ∼7.5 years with a low eccentricity and an Msin i of ∼3.4 MJup. Our discovery was made with the nearly 8 years of radial velocity follow-up at the Hobby–Eberly Telescope and Keck Observatory, including observations made as part of the Transit Ephemeris Refinement and Monitoring Survey effort to provide precise ephemerides to long-period planets for transit …