Stars, Interstellar Medium and the Galaxy Commons^™

Orbital Misalignment Of The Neptune-Mass Exoplanet Gj 436b With The Spin Of Its Cool Star, Vincent Bourrier, Christophe Lovis, Hervé Beust, David Ehrenreich, Gregory W. Henry, Nicola Astudillo-Defru, Romain Allart, Xavier Bonfils, Damien Ségransan, Xavier Delfosse, Heather M. Cegla, Aurélien Wyttenbach, Kevin Heng, Baptiste Lavie, Francesco Pepe

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The angle between the spin of a star and the orbital planes of its planets traces the history of the planetary system. Exoplanets orbiting close to cool stars are expected to be on circular, aligned orbits because of strong tidal interactions with the stellar convective envelope. Spin–orbit alignment can be measured when the planet transits its star, but such ground-based spectroscopic measurements are challenging for cool, slowly rotating stars. Here we report the three-dimensional characterization of the trajectory of an exoplanet around an M dwarf star, derived by mapping the spectrum of the stellar photosphere along the chord transited by …

Contemporaneous Imaging Comparisons Of The Spotted Giant Σ Geminorum Using Interferometric, Spectroscopic, And Photometric Data, Rachael M. Roettenbacher, John D. Monnier, Heidi Korhonen, Robert O. Harmon, Fabien Baron, Thomas Hackman, Gregory W. Henry, Gail H. Schaefer, Klaus G. Strassmeier, Michael Weber, Theo A. Ten Brummelaar

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Nearby active stars with relatively rapid rotation and large starspot structures offer the opportunity to compare interferometric, spectroscopic, and photometric imaging techniques. In this paper, we image a spotted star with three different methods for the first time. The giant primary star of the RS Canum Venaticorum binary σ Geminorum (σ Gem) was imaged for two epochs of interferometric, high-resolution spectroscopic, and photometric observations. The light curves from the reconstructions show good agreement with the observed light curves, supported by the longitudinally consistent spot features on the different maps. However, there is strong disagreement in the spot latitudes across the …

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

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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 …

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. X. Hd 96511, Hr 7578, And Kz Andromedae, Francis C. Fekel, Gregory W. Henry, Jocelyn Tomkin

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From an extensive number of newly acquired radial velocities we determine the orbital elements for three late-type dwarf systems, HD 96511, HR 7578, and KZ And. The orbital periods are 18.89737 ± 0.00002, 46.81610 ± 0.00006, and 3.0329113 ± 0.0000005 days, respectively, and all three systems are eccentric, although KZ And is just barely so. We have detected lines of the secondary of HD 96511 for the first time. The orbital dimensions (a1 sin i and a2 sin i) and minimum masses (m1 sin3 i and m2 sin3 i) of the binary components all have accuracies of 0.2% or better. …

Orbital Elements And Stellar Parameters Of The Active Binary Ux Arietis, Christian A. Hummel, John D. Monnier, Rachael M. Roettenbacher, Guillermo Torres, Gregory W. Henry, Heidi Korhonen, Anthony Beasley, Gail H. Schaefer, Nils H. Turner, Theo A. Ten Brummelaar, Chris D. Farrington, Judit Sturmann, Laszlo Sturmann, Frédérique Baron, Stefan Kraus

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Stellar activity observed as large surface spots, radio flares, or emission lines is often found in binary systems. UX Arietis exhibits these signs of activity, originating on the K0 subgiant primary component. Our aim is to resolve the binary, measure the orbital motion, and provide accurate stellar parameters such as masses and luminosities to aid in the interpretation of the observed phenomena. Using the CHARA six-telescope optical long-baseline array on Mount Wilson, California, we obtained amplitudes and phases of the interferometric visibility on baselines up to 330 m in length, resolving the two components of the binary. We reanalyzed archival …

Kepler Sheds New And Unprecedented Light On The Variability Of A Blue Supergiant: Gravity Waves In The O9.5iab Star Hd 188209, Conny Aerts, Sergio Símon-Díaz, Steven Bloemen, Jonas Debosscher, Péter I. Pápics, Steve Bryson, M. Still, Ehsan Moravveji, Michael H. Williamson, Frank Grundahl, Mads Fredslund Andersen, Victoria Antoci, Pere L. Pallé, Jørgen Christensen-Dalsgaard, Tamara M. Rogers

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Stellar evolution models are most uncertain for evolved massive stars. Asteroseismology based on high-precision uninterrupted space photometry has become a new way to test the outcome of stellar evolution theory and was recently applied to a multitude of stars, but not yet to massive evolved supergiants.Our aim is to detect, analyse and interpret the photospheric and wind variability of the O9.5 Iab star HD 188209 from Kepler space photometry and long-term high-resolution spectroscopy. We used Kepler scattered-light photometry obtained by the nominal mission during 1460 d to deduce the photometric variability of this O-type supergiant. In addition, we assembled and …

General Model For Light Curves Of Chromospherically Active Binary Stars, Lauri Jetsu, Gregory W. Henry, Jyri J. Lehtinen

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The starspots on the surface of many chromospherically active binary stars concentrate on long-lived active longitudes separated by 180°. Shifts in activity between these two longitudes, the "flip-flop" events, have been observed in single stars like FK Comae and binary stars like σ Geminorum. Recently, interferometry has revealed that ellipticity may at least partly explain the flip-flop events in σ Geminorum. This idea was supported by the double-peaked shape of the long-term mean light curve of this star. Here we show that the long-term mean light curves of 14 chromospherically active binaries follow a general model that explains the connection …

Characterization Of The Wolf 1061 Planetary System, Stephen R. Kane, Kaspar Von Braun, Gregory W. Henry, Miranda A. Waters, Tabetha S. Boyajian, Andrew W. Mann

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A critical component of exoplanetary studies is an exhaustive characterization of the host star, from which the planetary properties are frequently derived. Of particular value are the radius, temperature, and luminosity, which are key stellar parameters for studies of transit and habitability science. Here we present the results of new observations of Wolf 1061, known to host three super-Earths. Our observations from the Center for High Angular Resolution Astronomy interferometric array provide a direct stellar radius measurement of 0.3207 ± 0.0088 R⊙, from which we calculate the effective temperature and luminosity using spectral energy distribution models. We obtained 7 yr …

Infrared Spectroscopy Of Symbiotic Stars. Xi. Orbits For Southern S-Type Systems: Hen 3-461, Sy Mus, Hen 3-828, And Ar Pav, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood

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Employing new infrared radial velocities, we have computed spectroscopic orbits of the cool giants in four southern S-type symbiotic systems. The orbits for two of the systems, Hen 3-461 and Hen 3-828, have been determined for the first time, while orbits of the other two, SY Mus and AR Pav, have previously been determined. For the latter two systems, we compare our results with those in the literature. The low mass of the secondary of SY Mus suggests that it has gone through a common envelope phase. Hen 3-461 has an orbital period of 2271 days, one of the longest …

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

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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 ${R}_{1}=6.356\pm 0.056\,{R}_{\odot }$ …

Very Low-Mass Stellar And Substellar Companions To Solar-Like Stars From Marvels. Vi. A Giant Planet And A Brown Dwarf Candidate In A Close Binary System Hd 87646, Bo Ma, Jian Ge, Alex Wolszczan, Matthew W. Muterspaugh, Brian Lee, Gregory W. Henry, Donald P. Schneider, Eduardo L. Martín, Andrzej Niedzielski, Jiwei Xie, Scott W. Fleming, Neil Thomas, Michael Williamson, Zhaohuan Zhu, Eric Agol, Dmitry Bizyaev, Luiz Nicolaci Da Costa, Peng Jiang, Aldo Fabricio Martinez Fiorenzano, Jonay I. González Hernández, Pengcheng Guo, Nolan Grieves, Rui Li, Jane Liu, Suvrath Mahadevan, Tsevi Mazeh, Duy Cuong Nguyen, Martin Paegert, Sirinrat Sithajan, Keivan Stassun, Sivarani Thirupathi, Julian C. Van Eyken, Xiaoke Wan, Ji Wang, John P. Wisniewski, Bo Zhao, Shay Zucker

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We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using the Exoplanet Tracker at the Kitt Peak National Observatory, the High Resolution Spectrograph at the Hobby Eberley telescope, the "Classic" spectrograph …

Torsional Oscillations And Observed Rotational Period Variations In Early-Type Stars, Jiří Krtička, Zdeněk Mikulášek, Gregory W. Henry, Petr Kurfürst, Marian Karlický

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Some chemically peculiar stars in the upper main sequence show rotational period variations of unknown origin. We propose that these variations are a consequence of the propagation of internal waves in magnetic rotating stars that lead to the torsional oscillations of the star. We simulate the magnetohydrodynamic waves and calculate resonant frequencies for two stars that show rotational variations: CU Vir and HD 37776. We provide updated analyses of rotational period variations in these stars and compare our results with numerical models. For CU Vir, the length of the observed rotational period cycle, | $\mathit {\Pi }=67.6(5)$ | yr, can …

Spectroscopic Orbits For 15 Late-Type Stars, Daryl W. Willmarth, Francis C. Fekel, Helmut A. Abt, Dimitri Pourbaix

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Spectroscopic orbital elements are determined for 15 stars with periods from 8 to 6528 days with six orbits computed for the first time. Improved astrometric orbits are computed for two stars and one new orbit is derived. Visual orbits were previously determined for four stars, four stars are members of multiple systems, and five stars have Hipparcos "G" designations or have been resolved by speckle interferometry. For the nine binaries with previous spectroscopic orbits, we determine improved or comparable elements. For HD 28271 and HD 200790, our spectroscopic results support the conclusions of previous authors that the large values of …

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

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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. …

Activity Trends In Young Solar-Type Stars, Jyri J. Lehtinen, Lauri Jetsu, Thomas Hackman, Perttu Kajatkari, Gregory W. Henry

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Aims. We study a sample of 21 young and active solar-type stars with spectral types ranging from late F to mid K and characterize the behaviour of their activity.

Methods. We apply the continuous period search (CPS) time series analysis method on Johnson B- and V-band photometry of the sample stars, collected over a period of 16 to 27 years. Using the CPS method, we estimate the surface differential rotation and determine the existence and behaviour of active longitudes and activity cycles on the stars. We supplement the time series results by calculating new log R'_HK = …

The Spectroscopic Orbits Of Five Γ Doradus Stars, Francis C. Fekel, Gregory W. Henry, Dimitri Pourbaix

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We have determined the spectroscopic orbits of five γ Dor variables, HD 776, HD 6568, HD 17310, HD 19684, and HD 62196. Their orbital periods range from 27.8 to 1163 days and their eccentricities from 0.01 to 0.65. Of the five systems, only HD 19684 shows lines of its binary companion, but those lines are always so weak and blended with the lines of the primary that we were unable to measure them satisfactorily. The velocity residuals of the orbital fits were searched for periodicities associated with pulsation. No clear, convincing case for velocity periodicities in the residuals was found …

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

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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 …

Redicting The Α Comae Berenices Time Of Eclipse: How 3 Ambiguous Measurements Out Of 609 Caused A 26 Year Binary's Eclipse To Be Missed, Matthew W. Muterspaugh, Marcella J. P. Wijngaarden, Hubertus F. Henrichs, Benjamin F. Lane, William I. Hartkopf, Gregory W. Henry, Gail H. Schaefer, Chris D. Farrington, Christian A. Hummel, Robert T. Zavala

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The dwarf stars in the 26 year period binary α Com were predicted to eclipse each other in early 2015. That prediction was based on an orbit model made with over 600 astrometric observations using micrometers, speckle interferometry, and long baseline optical interferometry. Unfortunately, it has been realized recently that the position angle measurements for three of the observations from ∼100 years ago were in error by 180°, which warped the orbital fit. The eclipse was likely 2 months earlier than predicted (MJD 56979, 2014 November 18 UT, 7 days before the first photometric observations of this system for the …

Sun-Like Magnetic Cycles In The Rapidly Rotating Young Solar Analog Hd 30495, Ricky Egeland, Travis S. Metcalfe, Jeffrey C. Hall, Gregory W. Henry

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A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial (∼2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has …

Detecting The Companions And Ellipsoidal Variations Of Rs Cvn Primaries. Ii. O Draconis, A Candidate For Recent Low-Mass Companion Ingestion, Rachael M. Roettenbacher, John D. Monnier, Francis C. Fekel, Gregory W. Henry, Heidi Korhonen, David W. Latham, Matthew W. Muterspaugh, Michael H. Williamson, Fabien Baron, Theo A. Ten Brummelaar, Xiao Che, Robert O. Harmon, Gail H. Schaefer, Nicholas J. Scott, Judit Sturmann, Laszlo Sturmann, Nils H. Turner

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To measure the stellar and orbital properties of the metal-poor RS CVn binary o Draconis (o Dra), we directly detect the companion using interferometric observations obtained with the Michigan InfraRed Combiner at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array. The H-band flux ratio between the primary and secondary stars is the highest confirmed flux ratio (370 ± 40) observed with long-baseline optical interferometry. These detections are combined with radial velocity data of both the primary and secondary stars, including new data obtained with the Tillinghast Reflector Echelle Spectrograph on the Tillinghast Reflector at the Fred Lawrence …

Infrared Spectroscopy Of Symbiotic Stars. X. Orbits For Three S-Type Systems: V1044 Centauri, Hen 3-1213, And Ss 73-96, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood

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Employing new infrared radial velocities, we have computed orbits of the cool giants in three southern S-type symbiotic systems. The orbit for V1044 Cen, an M5.5 giant, has a period of 985 days and a modest eccentricity of 0.16. Hen 3-1213 is a K4 giant, yellow symbiotic with an orbital period of 533 days and a similar eccentricity of 0.18. For the M2 giant SS 73-96 the orbital period is 828 days, and this system has a somewhat larger eccentricity of 0.26. Measurement of the H i Paschen δ emission lines, which may at least partially reflect the motion of …

Multiperiodicity, Modulations, And Flip-Flops In Variable Star Light Curves. Iii. Carrier Fit Analysis Of Lq Hydrae Photometry For 1982–2014, Nigul Olspert, Maarit J. Käpylä, Jaan Pelt, Elizabeth M. Cole, Thomas Hackman, Jyri J. Lehtinen, Gregory W. Henry

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Aims. We study LQ Hya photometry for 1982–2014 with the carrier fit (CF) method and compare our results to earlier photometric analysis and recent Doppler imaging maps.

Methods. As the rotation period of the object is not known a priori, we utilize different types of statistical methods first (least-squares fit of harmonics, phase dispersion statistics) to estimate various candidates for the carrier period for the CF method. Secondly, a global fit to the whole data set and local fits to shorter segments are computed with the period that is found to be optimal.

Results. The harmonic least-squares analysis of all …

Periodicity In Some Light Curves Of The Solar Analogue V352 Canis Majoris, Perttu Kajatkari, Lauri Jetsu, Elizabeth M. Cole, Thomas Hackman, Gregory W. Henry, Sirkka-Liisa Joutsiniemi, Jyri J. Lehtinen, V. Mäkelä, Sebastian Porceddu, Kyösti Ryynänen, V. Solea

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Aims. We applied the Continuous Period Search (CPS) method to 14 yr of V-band photometry of the active G6.5 solar analog V352 CMa. Our aim was to show that CPS can successfully model the presence or absence of periodicity in low-amplitude light curves.

Methods. CPS computes values for the mean brightness, photometric period, amplitude and minimum of selected datasets. We also applied the Power Spectrum Method (PSM) to these datasets and compared the performance of this frequently applied method to that of CPS.

Results. We found an apparent 11.7 ± 0.5 yr cycle in the mean brightness. The mean of …

Stellar Activity And Its Implications For Exoplanet Detection On Gj 176, Paul Robertson, Michael Endl, Gregory W. Henry, William D. Cochran, Phillip J. Macqueen, Michael H. Williamson

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We present an in-depth analysis of stellar activity and its effects on radial velocity (RV) for the M2 dwarf GJ 176 based on spectra taken over 10 yr from the High Resolution Spectrograph on the Hobby–Eberly Telescope. These data are supplemented with spectra from previous observations with the HIRES and HARPS spectrographs, and V- and R-band photometry taken over six years at the Dyer and Fairborn observatories. Previous studies of GJ 176 revealed a super-Earth exoplanet in an 8.8-day orbit. However, the velocities of this star are also known to be contaminated by activity, particularly at the 39-day stellar rotation …

Hd 207651: A Composite Spectrum Triple System, Francis C. Fekel

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From numerous radial velocities obtained at KPNO and Fairborn Observatory, we have determined the orbital elements of the composite spectrum triple system HD 207651. This system consists of a broad-lined A8 V star and an unseen M dwarf companion in a 1.470739 days orbit. Variations of the center-of-mass velocity of this short-period system and velocity variations of a narrow-lined F7: V star have an orbital period of 724.1 days or 1.98 yr and an eccentricity of 0.39. The revised Hipparcos parallax, corresponding to a distance of 255 pc, appears to be too small to yield consistent properties. Instead, we adopt …

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. Ix. Hd 54371, Hr 2692, And 16 Ursa Majoris, Francis C. Fekel, Michael H. Williamson, Matthew W. Muterspaugh, Dimitri Pourbaix, Daryl W. Willmarth, Jocelyn Tomkin

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With extensive sets of new radial velocities we have determined orbital elements for three previously known spectroscopic binaries, HD 54371, HR 2692, and 16 UMa. All three systems have had the lines of their secondaries detected for the first time. The orbital periods range from 16.24 to 113.23 days, and the three binaries have modestly or moderately eccentric orbits. The secondary to primary mass ratios range from 0.50 to 0.64. The orbital dimensions (a1 sin i and a2 sin i) and minimum masses (m1 sin3 i and m2 sin3 i) of the binary components all have accuracies of $\leqslant $1%. …

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

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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. …

Hst Hot-Jupiter Transmission Spectral Survey: Haze In The Atmosphere Of Wasp-6b, Nikolay Nikolov, David K. Sing, Adam S. Burrows, Jonathan J. Fortney, Gregory W. Henry, Frederic Pont, Gilda E. Ballester, Suzanne Aigrain, Paul A. Wilson, Catherine M. Huitson, Neale P. Gibson, Jean-Michel Désert, Alain Lecavelier Des Etangs, Adam P. Showman, Alfred Vidal-Madjar, Hannah R. Wakeford, Kevin J. Zahnle

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We report Hubble Space Telescope optical to near-infrared transmission spectroscopy of the hot-Jupiter WASP-6b, measured with the Space Telescope Imaging Spectrograph and Spitzer's InfraRed Array Camera. The resulting spectrum covers the range 0.29–4.5 μm. We find evidence for modest stellar activity of WASP-6 and take it into account in the transmission spectrum. The overall main characteristic of the spectrum is an increasing radius as a function of decreasing wavelength corresponding to a change of Δ (Rp / R*) = 0.0071 from 0.33 to 4.5 μm. The spectrum suggests an effective extinction cross-section with a power law of index consistent with …

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 …

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

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No abstract provided.