Physical Sciences and Mathematics | Open Access Articles

Kelt-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-Mass Companion Transiting A Mid-F Star, R. J. Siverd, T. G. Beatty, J. Pepper, J. D. Eastman, K. Collins, A. Bieryla, D. W. Latham, L. A. Buchhave, Eric L.N. Jensen, J. R. Crepp, R. Street, K. G. Stassun, B. S. Gaudi, P. Berlind, M. L. Calkins, D. L. Depoy, G. A. Esquerdo, B. J. Fulton, G. Fürész, J. C. Geary, A. Gould, L. Hebb, J. F. Kielkopf, J. L. Marshall, R. Pogge, K. Z. Stanek, R. P. Stefanik, A. H. Szentgyorgyi, M. Trueblood, P. Trueblood, A. M. Stutz, J. L. Van Saders

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We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) transit survey. A joint analysis of the spectroscopic, radial velocity, and photometric data indicates that the V = 10.7 primary is a mildly evolved mid-F star with T-eff = 6516 +/- 49 K, log g = 4.228(-0.021)(+0.014), and [Fe/H] = 0.052 +/- 0.079, with an inferred mass M* = 1.335 +/- 0.063M(circle dot) and radius R* = 1.471(-0.035)(+0.045) R-circle dot. The companion is a low-mass brown dwarf or a super-massive planet with mass M-P = 27.38 +/- 0.93 M-Jup and radius …

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The X-Ray View Of Ob Star Wind Structure And Dynamics, David H. Cohen

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High-resolution X-ray grating spectroscopy enables us to measure the kinematics and spatial distribution of the shock-heated wind plasma in O and early B stars, testing the predictions of the embedded wind shock scenario of massive star X-ray production. By fitting models to the resolved, Doppler broadened X-ray emission line profiles measured by the Chandra X-ray Observatory's grating spectrometer, we find an onset radius of X-ray production of roughly Ro = 1.5 R★ for the O supergiants, ζ Pup and HD 93129A. From the profile fitting we also find that the terminal velocity of the X-ray emitting plasma is consistent with …

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Kelt-2ab: A Hot Jupiter Transiting The Bright (V=8.77) Primary Star Of A Binary System, T. G. Beatty, J. Pepper, R. J. Siverd, J. D. Eastman, A. Bieryla, D. W. Latham, L. A. Buchhave, Eric L.N. Jensen, M. Manner, K. G. Stassun, B. S. Gaudi, P. Berlind, M. L. Calkins, K. Collins, D. L. Depoy, G. A. Esquerdo, B. J. Fulton, G. Fürész, J. C. Geary, A. Gould, L. Hebb, J. F. Kielkopf, J. L. Marshall, R. Pogge, K. Z. Stanek, R. P. Stefanik, R. Street, A. H. Szentgyorgyi, M. Trueblood, P. Trueblood, A. M. Stutz

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We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V = 8.77) primary star of the HD 42176 binary system. The host is a slightly evolved late F-star likely in the very short-lived "blue-hook" stage of evolution, with T-eff = 6148 +/- 48 K, log g = 4.030(-0.026)(+0.015) and [Fe/H] = 0.034 +/- 0.78. The inferred stellar mass is M-* = 1.314(-0.060)(+0.063) M-circle dot and the star has a relatively large radius of R-* = 1.836(-0.046)(+0.066) R-circle dot. The planet is a typical hot Jupiter with period 4.1137913 +/- 0.00001 days and a mass of M-P = …

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The Hd 192263 System: Planetary Orbital Period And Stellar Variability Disentangled, D. Dragomir, S. R. Kane, G. W. Henry, D. R. Ciardi, D. A. Fischer, A. W. Howard, Eric L.N. Jensen, G. Laughlin, S. Mahadevan, J. M. Matthews, G. Pilyavsky, K. Von Braun, S. X. Wang, J. T. Wright

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As part of the Transit Ephemeris Refinement and Monitoring Survey, we present new radial velocities and photometry of the HD 192263 system. Our analysis of the already available Keck-HIRES and CORALIE radial velocity measurements together with the five new Keck measurements we report in this paper results in improved orbital parameters for the system. We derive constraints on the size and phase location of the transit window for HD 192263b, a Jupiter-mass planet with a period of 24.3587 +/- 0.0022 days. We use 10 years of Automated Photoelectric Telescope photometry to analyze the stellar variability and search for planetary transits. …

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A Possible Detection Of Occultation By A Proto-Planetary Clump In Gm Cephei, W. P. Chen, S. C.-L. Hu, R. Errmann, C. Adam, S. Baar, A. Berndt, L. Bukowiecki, D. P. Dimitrov, T. Eisenbeiss, S. Fiedler, C. Ginski, C. Gräfe, J. K. Guo, M. M. Hohle, H. Y. Hsiao, R. Janulis, M. Kitze, H. C. Lin, C. S. Lin, G. Maciejewski, C. Marka, L. Marschall, M. Moualla, M. Mugrauer, R. Neuhäuser, T. Pribulla, S. Raetz, T. Röll, E. Schmidt, J. Schmidt, T. O.B. Schmidt, M. Seeliger, L. Trepl, C. Briceño, R. Chini, Eric L.N. Jensen, E. H. Nikogossian, A. K. Pandey, J. Sperauskas, H. Takahashi, F. M. Walter, Z. Y. Wu, X. Zhou

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GM Cephei (GM Cep), in the young (similar to 4 Myr) open cluster Trumpler 37, has been known to be an abrupt variable and to have a circumstellar disk with a very active accretion. Our monitoring observations in 2009-2011 revealed that the star showed sporadic flare events, each with a brightening of less than or similar to 0.5 mag lasting for days. These brightening events, associated with a color change toward blue, should originate from increased accretion activity. Moreover, the star also underwent a brightness drop of similar to 1 mag lasting for about a month, during which time the …

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A Generalized Porosity Formalism For Isotropic And Anisotropic Effective Opacity And Its Effects On X-Ray Line Attenuation In Clumped O Star Winds, J. O. Sundqvist, S. P. Owocki, David H. Cohen, M. A. Leutenegger, R. H.D. Townsend

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We present a generalized formalism for treating the porosity-associated reduction in continuum opacity that occurs when individual clumps in a stochastic medium become optically thick. As in previous work, we concentrate on developing bridging laws between the limits of optically thin and thick clumps. We consider geometries resulting in either isotropic or anisotropic effective opacity, and, in addition to an idealized model in which all clumps have the same local overdensity and scale, we also treat an ensemble of clumps with optical depths set by Markovian statistics. This formalism is then applied to the specific case of boundfree absorption of …

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Physics & Astronomy Faculty Works

The X-Ray View Of Ob Star Wind Structure And Dynamics, David H. Cohen

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

The Hd 192263 System: Planetary Orbital Period And Stellar Variability Disentangled, D. Dragomir, S. R. Kane, G. W. Henry, D. R. Ciardi, D. A. Fischer, A. W. Howard, Eric L.N. Jensen, G. Laughlin, S. Mahadevan, J. M. Matthews, G. Pilyavsky, K. Von Braun, S. X. Wang, J. T. Wright

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

A Generalized Porosity Formalism For Isotropic And Anisotropic Effective Opacity And Its Effects On X-Ray Line Attenuation In Clumped O Star Winds, J. O. Sundqvist, S. P. Owocki, David H. Cohen, M. A. Leutenegger, R. H.D. Townsend

Physics & Astronomy Faculty Works