Physical Sciences and Mathematics | Open Access Articles

On The Stellar Companion To The Exoplanet Hosting Star 30 Arietis B, S. R. Kane, T. Barclay, M. Hartmann, A. P. Hatzes, Eric L. N. Jensen, D. R. Ciardi, D. Huber, J. T. Wright, E. V. Quintana

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A crucial aspect of understanding planet formation is determining the binarity of the host stars. Results from radial velocity (RV) surveys and the follow-up of Kepler exoplanet candidates have demonstrated that stellar binarity certainly does not exclude the presence of planets in stable orbits and the configuration may in fact be relatively common. Here we present new results for the 30 Arietis system which confirms that the B component hosts both planetary and stellar companions. Keck AO imaging provides direct detection of the stellar companion and additional RV data are consistent with an orbiting star. We present a revised orbit …

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Using Protoplanetary Disks To Weigh The Youngest Stars And Constrain The Earliest Stages Of Stellar Evolution, I. Czekala, S. Andrews, Eric L. N. Jensen, K. Stassun, D. W. Latham, D. Wilner, G. Torres

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Mass is the fundamental property that determines the fate of a star. In particular, the masses of young stars are of great relevance to many astrophysical problems, including star and planet formation. We have developed a novel approach that combines spatially resolved sub-millimeter spectral line imaging and optical/near-infrared high resolution spectroscopy to derive the fundamental properties of a young star: mass, temperature, and radius. By applying our technique to a sample of pre-main sequence stars, we are mapping out a dynamically-calibrated Hertzsprung-Russell diagram for the express purpose of evaluating pre-main sequence evolutionary models. Looking forward, ALMA is poised to deliver …

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X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, David H. Cohen, G. A. Wade, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, M. Gagné

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We observed NGC 1624-2, the O-type star with the largest known magnetic field (Bp ∼ 20 kG), in X-rays with the Advanced CCD Imaging Spectrometer (ACIS-S) camera on-board the Chandra X-ray Observatory. Our two observations were obtained at the minimum and maximum of the periodic Hα emission cycle, corresponding to the rotational phases where the magnetic field is the closest to equator-on and pole-on, respectively. With these observations, we aim to characterize the star's magnetosphere via the X-ray emission produced by magnetically confined wind shocks. Our main findings are as follows. (i) The observed spectrum of NGC 1624-2 is hard, …

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Detection Of 610-Mhz Radio Emission From Hot Magnetic Stars, P. Chandra, G. A. Wade, J. O. Sundqvist, D. Oberoi, J. H. Grunhut, A. Ud-Doula, V. Petit, David H. Cohen, M. E. Oksala, A. David-Uraz

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We have carried out a study of radio emission from a small sample of magnetic O- and B-type stars using the Giant Metrewave Radio Telescope, with the goal of investigating their magnetospheres at low frequencies. These are the lowest frequency radio measurements ever obtained of hot magnetic stars. The observations were taken at random rotational phases in the 1390 and the 610 MHz bands. Out of the eight stars, we detect five B-type stars in both the 1390 and the 610 MHz bands. The three O-type stars were observed only in the 1390 MHz band, and no detections were obtained. …

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Kelt-8b: A Highly Inflated Transiting Hot Jupiter And A New Technique For Extracting High-Precision Radial Velocities From Noisy Spectra, B. J. Fulton, K. A. Collins, B. S. Gaudi, K. G. Stassun, J. Pepper, T. G. Beatty, R. J. Siverd, K. Penev, A. W. Howard, C. Baranec, G. Corfini, J. D. Eastman, J. Gregorio, N. M. Law, M. B. Lund, T. E. Oberst, M. T. Penny, R. Riddle, J. E. Rodriguez, D. J. Stevens, R. Zambelli, C. Ziegler, A. Bieryla, G. D'Ago, D. L. Depoy, Eric L.N. Jensen, J. F. Kielkopf, D. W. Latham, M. Manner, J. Marshall, K. K. Mcleod, P. A. Reed

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We announce the discovery of a highly inflated transiting hot Jupiter by the KELT-North survey. A global analysis including constraints from isochrones indicates that the V = 10.8 host star (HD 343246) is a mildly evolved, G dwarf with {T}_{eff}={5754}_-55⁺⁵⁴ K, {log} g={4.078}_-0.054^+0.049, [{Fe}/{{H}}]=0.272+/- 0.038, an inferred mass {M}_*={1.211}_-0.066^+0.078 {M}_☉, and radius {R}_*={1.67}_-0.12^+0.14 {R}_☉. The planetary companion has a mass {M}_{{P}}={0.867}_-0.061^+0.065 M_J, radius {R}_{{P}}={1.86}_-0.16^+0.18 R_J, surface gravity {log} {g} …

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Ground-Based Transit Observations Of The Hat-P-18, Hat-P-19, Hat-P-27/Wasp40 And Wasp-21 Systems, M. Seeliger, M. Kitze, R. Errmann, S. Richter, J. M. Ohlert, W. P. Chen, J. K. Guo, E. Göğüş, T. Güver, B. Aydın, S. Mottola, S. Hellmich, M. Fernandez, F. J. Aceituno, D. Dimitrov, D. Kjurkchieva, Eric L.N. Jensen, David H. Cohen, E. Kundra, T. Pribulla, M. Vaňko, J. Budaj, M. Mallonn, Z.-Y. Wu, X. Zhou, St. Raetz, C. Adam, T. O. B. Schmidt, A. Ide, M. Mugrauer, L. Marschall, M. Hackstein, R. Chini, M. Haas, T. Ak, E. Güzel, A. Özdönmez, C. Ginski, C. Marka, J. G. Schmidt, B. Dincel, K. Werner, A. Dathe, J. Greif, V. Wolf, S. Buder, A. Pannicke, D. Puchalski, R. Neuhäuser

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As part of our ongoing effort to investigate transit timing variations (TTVs) of known exoplanets, we monitored transits of the four exoplanets HAT-P-18b, HAT-P-19b, HAT-P-27b/WASP-40b and WASP-21b. All of them are suspected to show TTVs due to the known properties of their host systems based on the respective discovery papers. During the past three years 46 transit observations were carried out, mostly using telescopes of the Young Exoplanet Transit Initiative. The analyses are used to refine the systems’ orbital parameters. In all cases we found no hints for significant TTVs, or changes in the system parameters inclination, fractional stellar radius …

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Confirming Hd 23478 As A New Magnetic B Star Hosting An Hα-Bright Centrifugal Magnetosphere, J. Sikora, G. A. Wade, D. A. Bohlender, C. Neiner, M. E. Oksala, M. Shultz, David H. Cohen, A. Ud-Doula, J. Grunhut, D. Monin, S. Owocki, V. Petit, T. Rivinus, R. H. D. Townsend

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In this paper, we report 23 magnetic field measurements of the B3IV star HD 23478: 12 obtained from high-resolution Stokes V spectra using the ESPaDOnS (Canada–France–Hawaii Telescope) and Narval (Télescope Bernard Lyot) spectropolarimeters, and 11 from medium-resolution Stokes V spectra obtained with the DimaPol spectropolarimeter (Dominion Astronomical Observatory). HD 23478 was one of two rapidly rotating stars identified as potential ‘centrifugal magnetosphere’ hosts based on IR observations from the Apache Point Observatory Galactic Evolution Experiment survey. We derive basic physical properties of this star including its mass (M=6.1+0.8−0.7M⊙), effective temperature (Teff = 20 ± 2 kK), radius (R=2.7+1.6−0.9R⊙), and age …

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Kelt-7b: A Hot Jupiter Transiting A Bright V = 8.54 Rapidly Rotating F-Star, A. Bieryla, K. Collins, T. G. Beatty, J. Eastman, R. J. Siverd, J. Pepper, B. S. Gaudi, K. G. Stassun, C. Cañas, D. W. Latham, L. A. Buchhave, R. Sanchis-Ojeda, J. N. Winn, Eric L.N. Jensen, J. F. Kielkopf, K. K. Mcleod, J. Gregorio, K. D. Colón, R. Street, R. Ross, M. Penny, S. N. Mellon, T. E. Oberst, B. J. Fulton, J. Wang, P. Berlind, M. L. Calkins, G. A. Esquerdo, D. L. Depoy, A. Gould, J. Marshall, R. Pogge, M. Trueblood, P. Trueblood

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We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of 1.28+/- 0.18 M_J, radius of {1.533}_-0.047^+0.046 R_J, and an orbital period of 2.7347749+/- 0.0000039 days. The bright host star (HD 33643; KELT-7) is an F-star with V = 8.54, T_eff = 6789{}_-49⁺⁵⁰ K, [Fe/H] = {0.139}_-0.081^+0.075, and {log}\{\text{}}g\=4.149+/- 0.019. It has a mass of {1.535}_-0.054^+0.066 M_☉, a radius of {1.732}_-0.045^+0.043 R_☉, and is the fifth most massive, fifth hottest, and the ninth brightest star known to …

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A Disk-Based Dynamical Mass Estimate For The Young Binary Ak Sco, I. Czekala, S. M. Andrews, Eric L.N. Jensen, K. G. Stassun, G. Torres, D. J. Wilner

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We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust in the disk orbiting the pre-main sequence (pre-MS) binary AK Sco. By forward-modeling the disk velocity field traced by CO J = 2-1 line emission, we infer the mass of the central binary, {M}_*=2.49+/- 0.10 {M}_☉, a new dynamical measurement that is independent of stellar evolutionary models. Assuming the disk and binary are co-planar within ̃2°, this disk-based binary mass measurement is in excellent agreement with constraints from radial velocity monitoring of the combined stellar spectra. These ALMA results are …

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Full-Text Articles in Physical Sciences and Mathematics

On The Stellar Companion To The Exoplanet Hosting Star 30 Arietis B, S. R. Kane, T. Barclay, M. Hartmann, A. P. Hatzes, Eric L. N. Jensen, D. R. Ciardi, D. Huber, J. T. Wright, E. V. Quintana

Physics & Astronomy Faculty Works

Using Protoplanetary Disks To Weigh The Youngest Stars And Constrain The Earliest Stages Of Stellar Evolution, I. Czekala, S. Andrews, Eric L. N. Jensen, K. Stassun, D. W. Latham, D. Wilner, G. Torres

Physics & Astronomy Faculty Works

X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, David H. Cohen, G. A. Wade, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, M. Gagné

Physics & Astronomy Faculty Works

Detection Of 610-Mhz Radio Emission From Hot Magnetic Stars, P. Chandra, G. A. Wade, J. O. Sundqvist, D. Oberoi, J. H. Grunhut, A. Ud-Doula, V. Petit, David H. Cohen, M. E. Oksala, A. David-Uraz

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

Confirming Hd 23478 As A New Magnetic B Star Hosting An Hα-Bright Centrifugal Magnetosphere, J. Sikora, G. A. Wade, D. A. Bohlender, C. Neiner, M. E. Oksala, M. Shultz, David H. Cohen, A. Ud-Doula, J. Grunhut, D. Monin, S. Owocki, V. Petit, T. Rivinus, R. H. D. Townsend

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

A Disk-Based Dynamical Mass Estimate For The Young Binary Ak Sco, I. Czekala, S. M. Andrews, Eric L.N. Jensen, K. G. Stassun, G. Torres, D. J. Wilner

Physics & Astronomy Faculty Works