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Articles 121 - 150 of 221
Full-Text Articles in Astrophysics and Astronomy
Kelt-16b: A Highly Irradiated, Ultra-Short Period Hot Jupiter Nearing Tidal Disruption, T. E. Oberst, J. E. Rodriguez, K. D. Colón, D. Angerhausen, A. Bieryla, H. Ngo, D. J. Stevens, K. G. Stassun, B. S. Gaudi, J. Pepper, K. Penev, D. Mawet, D. W. Latham, T. M. Heintz, B. W. Osei, K. A. Collins, J. F. Kielkopf, T. Visgaitis, P. A. Reed, A. Escamilla, S. Yazdi, K. K. Mcleod, L. T. Lunsford, M. Spencer, M. D. Joner, J. Gregorio, C. Gaillard, K. Matt, M. T. Dumont, D. C. Stephens, David H. Cohen, Eric L.N. Jensen, S. C. Novati, V. Bozza, J. Labadie-Bartz, R. J. Siverd, M. B. Lund, T. G. Beatty, J. D. Eastman, M. T. Penny, M. Manner, R. Zambelli, B. J. Fulton, C. Stockdale, D. L. Depoy, J. L. Marshall, R. W. Pogge, A. Gould, M. Trueblood, P. Trueblood
Kelt-16b: A Highly Irradiated, Ultra-Short Period Hot Jupiter Nearing Tidal Disruption, T. E. Oberst, J. E. Rodriguez, K. D. Colón, D. Angerhausen, A. Bieryla, H. Ngo, D. J. Stevens, K. G. Stassun, B. S. Gaudi, J. Pepper, K. Penev, D. Mawet, D. W. Latham, T. M. Heintz, B. W. Osei, K. A. Collins, J. F. Kielkopf, T. Visgaitis, P. A. Reed, A. Escamilla, S. Yazdi, K. K. Mcleod, L. T. Lunsford, M. Spencer, M. D. Joner, J. Gregorio, C. Gaillard, K. Matt, M. T. Dumont, D. C. Stephens, David H. Cohen, Eric L.N. Jensen, S. C. Novati, V. Bozza, J. Labadie-Bartz, R. J. Siverd, M. B. Lund, T. G. Beatty, J. D. Eastman, M. T. Penny, M. Manner, R. Zambelli, B. J. Fulton, C. Stockdale, D. L. Depoy, J. L. Marshall, R. W. Pogge, A. Gould, M. Trueblood, P. Trueblood
Physics & Astronomy Faculty Works
We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright (V = 11.7) star TYC 2688-1839-1/KELT-16. A global analysis of the system shows KELT-16 to be an F7V star with ${T}_{\mathrm{eff}}=6236\pm 54$ K, $\mathrm{log}{g}_{\star }={4.253}_{-0.036}^{+0.031}$, $[\mathrm{Fe}/{\rm{H}}]=-{0.002}_{-0.085}^{+0.086}$, ${M}_{\star }={1.211}_{-0.046}^{+0.043}\,{M}_{\odot }$, and ${R}_{\star }\,={1.360}_{-0.053}^{+0.064}{R}_{\odot }$. The planet is a relatively high-mass inflated gas giant with ${M}_{{\rm{P}}}={2.75}_{-0.15}^{+0.16}{M}_{{\rm{J}}}$, ${R}_{{\rm{P}}}={1.415}_{-0.067}^{+0.084}{R}_{{\rm{J}}}$, density ${\rho }_{{\rm{P}}}=1.20\pm 0.18$ g cm−3, surface gravity $\mathrm{log}\,{g}_{{\rm{P}}}={3.530}_{-0.049}^{+0.042}$, and ${T}_{\mathrm{eq}}={2453}_{-47}^{+55}$ K. The best-fitting linear ephemeris is ${T}_{{\rm{C}}}=2457247.24791\pm 0.00019$ ${\mathrm{BJD}}_{\mathrm{TDB}}\ $and $P=0.9689951\pm 0.0000024$ day. KELT-16b joins WASP-18b, −19b, −43b, −103b, and HATS-18b as the only giant transiting planets …
A Jvla Survey Of The High-Frequency Radio Emission Of The Massive Magnetic B- And O-Type Stars, S. Kurapati, P. Chandra, G. Wade, David H. Cohen, A. David-Uraz, M. Gagne, J. Grunhut, M. E. Oksala, V. Petit, M. Shultz, J. Sundqvist, R. H. D. Townsend, A. Ud-Doula
A Jvla Survey Of The High-Frequency Radio Emission Of The Massive Magnetic B- And O-Type Stars, S. Kurapati, P. Chandra, G. Wade, David H. Cohen, A. David-Uraz, M. Gagne, J. Grunhut, M. E. Oksala, V. Petit, M. Shultz, J. Sundqvist, R. H. D. Townsend, A. Ud-Doula
Physics & Astronomy Faculty Works
We conducted a survey of seven magnetic O-type stars and eleven B-type stars with masses above 8 M⊙ using the Very Large Array in the 1, 3 and 13 cm bands. The survey resulted in a detection of two O- and two B-type stars. While the detected O-type stars – HD 37742 and HD 47129 – are in binary systems, the detected B-type stars, HD 156424 and ALS 9522, are not known to be in binaries. All four stars were detected at 3 cm, whereas three were detected at 1 cm and only one star was detected at 13 cm. …
An ‘Analytic Dynamical Magnetosphere’ Formalism For X-Ray And Optical Emission From Slowly Rotating Magnetic Massive Stars, S. P. Owocki, A. Ud-Doula, J. O. Sundqvist, V. Petit, David H. Cohen, R. H. D. Townsend
An ‘Analytic Dynamical Magnetosphere’ Formalism For X-Ray And Optical Emission From Slowly Rotating Magnetic Massive Stars, S. P. Owocki, A. Ud-Doula, J. O. Sundqvist, V. Petit, David H. Cohen, R. H. D. Townsend
Physics & Astronomy Faculty Works
Slowly rotating magnetic massive stars develop ‘dynamical magnetospheres’ (DMs), characterized by trapping of stellar wind outflow in closed magnetic loops, shock heating from collision of the upflow from opposite loop footpoints, and subsequent gravitational infall of radiatively cooled material. In 2D and 3D magnetohydrodynamic (MHD) simulations, the interplay among these three components is spatially complex and temporally variable, making it difficult to derive observational signatures and discern their overall scaling trends. Within a simplified, steady-state analysis based on overall conservation principles, we present here an ‘analytic dynamical magnetosphere’ (ADM) model that provides explicit formulae for density, temperature, and flow speed …
Kelt-17b: A Hot-Jupiter Transiting An A-Star In A Misaligned Orbit Detected With Doppler Tomography, G. Zhou, J. E. Rodriguez, K. A. Collins, T. Beatty, T. Oberst, T. M. Heintz, K. G. Stassun, D. W. Latham, R. B. Kuhn, A. Bieryla, M. B. Lund, J. Labadie-Bartz, R. J. Siverd, D. J. Stevens, B. S. Gaudi, J. Pepper, L. A. Buchhave, J. Eastman, K. Colón, P. Cargile, D. James, J. Gregorio, P. A. Reed, Eric L.N. Jensen, David H. Cohen, K. K. Mcleod, T. G. Tan, R. Zambelli, D. Bayliss, J. Bento, G. A. Esquerdo, P. Berlind, M. L. Calkins, K. Blancato, M. Manner, C. Samulski, C. Stockdale, P. Nelson, D. Stephens, I. Curtis, J. Kielkopf, B. J. Fulton, D. L. Depoy, J. L. Marshall, R. Pogge, A. Gould, M. Trueblood, P. Trueblood
Kelt-17b: A Hot-Jupiter Transiting An A-Star In A Misaligned Orbit Detected With Doppler Tomography, G. Zhou, J. E. Rodriguez, K. A. Collins, T. Beatty, T. Oberst, T. M. Heintz, K. G. Stassun, D. W. Latham, R. B. Kuhn, A. Bieryla, M. B. Lund, J. Labadie-Bartz, R. J. Siverd, D. J. Stevens, B. S. Gaudi, J. Pepper, L. A. Buchhave, J. Eastman, K. Colón, P. Cargile, D. James, J. Gregorio, P. A. Reed, Eric L.N. Jensen, David H. Cohen, K. K. Mcleod, T. G. Tan, R. Zambelli, D. Bayliss, J. Bento, G. A. Esquerdo, P. Berlind, M. L. Calkins, K. Blancato, M. Manner, C. Samulski, C. Stockdale, P. Nelson, D. Stephens, I. Curtis, J. Kielkopf, B. J. Fulton, D. L. Depoy, J. L. Marshall, R. Pogge, A. Gould, M. Trueblood, P. Trueblood
Physics & Astronomy Faculty Works
We present the discovery of a hot Jupiter transiting the V = 9.23 mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a ${1.31}_{-0.29}^{+0.28}\,{M}_{{\rm{J}}}$, ${1.525}_{-0.060}^{+0.065}\,{R}_{{\rm{J}}}$ hot-Jupiter in a 3.08-day period orbit misaligned at −115fdg9 ± 4fdg1 to the rotation axis of the star. The planet is confirmed via both the detection of the radial velocity orbit, and the Doppler tomographic detection of the shadow of the planet during two transits. The nature of the spin–orbit misaligned transit geometry allows us to place a constraint on the level of differential rotation in the host star; we find that KELT-17 is consistent with …
Kepler-1647b: The Largest And Longest-Period Kepler Transiting Circumbinary Planet, V. B. Kostov, J. A. Orosz, W. F. Welsh, L. R. Doyle, D. C. Fabrycky, N. Haghighipour, B. Quarles, D. R. Short, W. D. Cochran, M. End, E. B. Ford, J. Gregorio, T. C. Hinse, H. Isaacson, J. M. Jenkins, Eric L.N. Jensen, S. Kane, I. Kull, D. W. Latham, J. J. Lissauer, G. W. Marcy, T. Mazeh, T. W. A. Müller, J. Pepper, S. N. Quinn, D. Ragozzine, A. Shporer, J. H. Steffen, G. Torres, G. Windmiller, W. J. Borucki
Kepler-1647b: The Largest And Longest-Period Kepler Transiting Circumbinary Planet, V. B. Kostov, J. A. Orosz, W. F. Welsh, L. R. Doyle, D. C. Fabrycky, N. Haghighipour, B. Quarles, D. R. Short, W. D. Cochran, M. End, E. B. Ford, J. Gregorio, T. C. Hinse, H. Isaacson, J. M. Jenkins, Eric L.N. Jensen, S. Kane, I. Kull, D. W. Latham, J. J. Lissauer, G. W. Marcy, T. Mazeh, T. W. A. Müller, J. Pepper, S. N. Quinn, D. Ragozzine, A. Shporer, J. H. Steffen, G. Torres, G. Windmiller, W. J. Borucki
Physics & Astronomy Faculty Works
We report the discovery of a new Kepler transiting circumbinary planet (CBP). This latest addition to the still-small family of CBPs defies the current trend of known short-period planets orbiting near the stability limit of binary stars. Unlike the previous discoveries, the planet revolving around the eclipsing binary system Kepler-1647 has a very long orbital period (~1100 days) and was at conjunction only twice during the Kepler mission lifetime. Due to the singular configuration of the system, Kepler-1647b is not only the longest-period transiting CBP at the time of writing, but also one of the longest-period transiting planets. With a …
Planet Formation Imager (Pfi): Science Vision And Key Requirements, S. Kraus, J. D. Monnier, M. J. Ireland, G. Duchêne, C. Espaillat, S. Hönig, A. Juhasz, C. Mordasini, J. Olofsson, C. Paladini, K. Stassun, N. Turner, G. Vasisht, T. J. Harries, M. R. Bate, J.-F. Gonzalez, A. Matter, Z. Zhu, O. Panic, Z. Regaly, A. Morbidelli, F. Meru, S. Wolf, J. Ilee, J.-P. Berger, M. Zhao, Q. Kral, A. Morlok, A. Bonsor, D. Ciardi, S. R. Kane, K. Kratter, G. Laughlin, J. Pepper, S. Raymond, L. Labadie, R. P. Nelson, G. Weigelt, T. Ten Brummelaar, A. Pierens, R. Oudmaijer, W. Kley, B. Pope, Eric L.N. Jensen, A. Bayo, M. Smith, T. Boyajian, L. H. Quiroga-Nuñez, R. Millan-Gabet, A. Chiavassa, A. Gallenne, M. Reynolds, W.-J. De Wit, M. Wittkowski, F. Millour, P. Gandhi, C. Ramos Almeida, A. Alonso Herrero, C. Packham, M. Kishimoto, K. R. W. Tristram, J.-U. Pott, J. Surdej, D. Buscher, C. Haniff, S. Lacour, R. Petrov, S. Ridgway, P. Tuthill, G. Van Belle, P. Armitage, C. Baruteau, M. Benisty, B. Bitsch, S.-J. Paardekooper, C. Pinte, F. Masset, G. Rosotti
Planet Formation Imager (Pfi): Science Vision And Key Requirements, S. Kraus, J. D. Monnier, M. J. Ireland, G. Duchêne, C. Espaillat, S. Hönig, A. Juhasz, C. Mordasini, J. Olofsson, C. Paladini, K. Stassun, N. Turner, G. Vasisht, T. J. Harries, M. R. Bate, J.-F. Gonzalez, A. Matter, Z. Zhu, O. Panic, Z. Regaly, A. Morbidelli, F. Meru, S. Wolf, J. Ilee, J.-P. Berger, M. Zhao, Q. Kral, A. Morlok, A. Bonsor, D. Ciardi, S. R. Kane, K. Kratter, G. Laughlin, J. Pepper, S. Raymond, L. Labadie, R. P. Nelson, G. Weigelt, T. Ten Brummelaar, A. Pierens, R. Oudmaijer, W. Kley, B. Pope, Eric L.N. Jensen, A. Bayo, M. Smith, T. Boyajian, L. H. Quiroga-Nuñez, R. Millan-Gabet, A. Chiavassa, A. Gallenne, M. Reynolds, W.-J. De Wit, M. Wittkowski, F. Millour, P. Gandhi, C. Ramos Almeida, A. Alonso Herrero, C. Packham, M. Kishimoto, K. R. W. Tristram, J.-U. Pott, J. Surdej, D. Buscher, C. Haniff, S. Lacour, R. Petrov, S. Ridgway, P. Tuthill, G. Van Belle, P. Armitage, C. Baruteau, M. Benisty, B. Bitsch, S.-J. Paardekooper, C. Pinte, F. Masset, G. Rosotti
Physics & Astronomy Faculty Works
The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to ~100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the …
Kelt-10b: The First Transiting Exoplanet From The Kelt-South Survey - A Hot Sub-Jupiter Transiting A V=10.7 Early G-Star, R. B. Kuhn, J. E. Rodriguez, K. A. Collins, M. B. Lund, R. J. Siverd, K. D. Colón, J. Pepper, K. G. Stassun, P. A. Cargile, D. J. James, K. Penev, G. Zhou, D. Bayliss, T. G. Tan, I. A. Curtis, S. Udry, D. Segransan, D. Mawet, S. Dhital, J. Soutter, R. Hart, B. Carter, B. S. Gaudi, G. Myers, T. G. Beatty, J. D. Eastman, D. E. Reichart, J. B. Haislip, J. F. Kielkopf, A. Bieryla, D. W. Latham, Eric L.N. Jensen, T. E. Oberst, D. J. Stevens
Kelt-10b: The First Transiting Exoplanet From The Kelt-South Survey - A Hot Sub-Jupiter Transiting A V=10.7 Early G-Star, R. B. Kuhn, J. E. Rodriguez, K. A. Collins, M. B. Lund, R. J. Siverd, K. D. Colón, J. Pepper, K. G. Stassun, P. A. Cargile, D. J. James, K. Penev, G. Zhou, D. Bayliss, T. G. Tan, I. A. Curtis, S. Udry, D. Segransan, D. Mawet, S. Dhital, J. Soutter, R. Hart, B. Carter, B. S. Gaudi, G. Myers, T. G. Beatty, J. D. Eastman, D. E. Reichart, J. B. Haislip, J. F. Kielkopf, A. Bieryla, D. W. Latham, Eric L.N. Jensen, T. E. Oberst, D. J. Stevens
Physics & Astronomy Faculty Works
We report the discovery of KELT-10b, the first transiting exoplanet discovered using the KELT-South telescope. KELT-10b is a highly inflated sub-Jupiter mass planet transiting a relatively bright V = 10.7 star (TYC 8378-64-1), with Teff = 5948 ± 74 K, log g = 4.319_{-0.030}^{+0.020} and [Fe/H] = 0.09_{-0.10}^{+0.11}, an inferred mass M★ = 1.112_{-0.061}^{+0.055} M☉ and radius R★ = 1.209_{-0.035}^{+0.047} R☉. The planet has a radius Rp = 1.399_{-0.049}^{+0.069} RJ and mass Mp = 0.679_{-0.038}^{+0.039} MJ. The planet has an eccentricity consistent with zero and a semi-major axis a …
Kelt-14b And Kelt-15b: An Independent Discovery Of Wasp-122b And A New Hot Jupiter, J. E. Rodriguez, K. D. Colón, K. G. Stassun, D. Wright, P. A. Cargile, D. Bayliss, J. Pepper, K. A. Collins, R. B. Kuhn, M. B. Lund, R. J. Siverd, G. Zhou, B. S. Gaudi, C. G. Tinney, K. Penev, T. G. Tan, C. Stockdale, I. A. Curtis, D. James, S. Udry, D. Segransan, A. Bieryla, D. W. Latham, T. G. Beatty, J. D. Eastman, G. Myers, J. Bartz, J. Bento, Eric L.N. Jensen, T. E. Oberst, D. J. Stevens
Kelt-14b And Kelt-15b: An Independent Discovery Of Wasp-122b And A New Hot Jupiter, J. E. Rodriguez, K. D. Colón, K. G. Stassun, D. Wright, P. A. Cargile, D. Bayliss, J. Pepper, K. A. Collins, R. B. Kuhn, M. B. Lund, R. J. Siverd, G. Zhou, B. S. Gaudi, C. G. Tinney, K. Penev, T. G. Tan, C. Stockdale, I. A. Curtis, D. James, S. Udry, D. Segransan, A. Bieryla, D. W. Latham, T. G. Beatty, J. D. Eastman, G. Myers, J. Bartz, J. Bento, Eric L.N. Jensen, T. E. Oberst, D. J. Stevens
Physics & Astronomy Faculty Works
We report the discovery of KELT-14b and KELT-15b, two hot Jupiters from the KELT-South survey. KELT-14b, an independent discovery of the recently announced WASP-122b, is an inflated Jupiter mass planet that orbits a $\sim {5.0}_{-0.7}^{+0.3}$ Gyr, V = 11.0, G2 star that is near the main sequence turnoff. The host star, KELT-14 (TYC 7638-981-1), has an inferred mass ${M}_{*}$ = ${1.18}_{-0.07}^{+0.05}$ M⊙ and radius ${R}_{*}$ = $1.37\pm -0.08$ R⊙, and has ${T}_{{\rm{eff}}}$ = ${5802}_{-92}^{+95}$ K, $\mathrm{log}{g}_{*}$ = ${4.23}_{-0.04}^{+0.05}$ and $[{\rm{Fe}}/{\rm{H}}]$ = 0.33 ± −0.09. The planet orbits with a period of 1.7100588 ± 0.0000025 days (T0 = 2457091.02863 ± 0.00047) …
Stellar Activity And Exclusion Of The Outer Planet In The Hd 99492 System, S. R. Kane, B. Thirumalachari, G. W. Henry, N. R. Hinkel, Eric L. N. Jensen, T. S. Boyajian, D. A. Fischer, A. W. Howard, H. T. Isaacson, J. T. Wright
Stellar Activity And Exclusion Of The Outer Planet In The Hd 99492 System, S. R. Kane, B. Thirumalachari, G. W. Henry, N. R. Hinkel, Eric L. N. Jensen, T. S. Boyajian, D. A. Fischer, A. W. Howard, H. T. Isaacson, J. T. Wright
Physics & Astronomy Faculty Works
A historical problem for indirect exoplanet detection has been contending with the intrinsic variability of the host star. If the variability is periodic, it can easily mimic various exoplanet signatures, such as radial velocity (RV) variations that originate with the stellar surface rather than the presence of a planet. Here we present an update for the HD 99492 planetary system, using new RV and photometric measurements from the Transit Ephemeris Refinement and Monitoring Survey. Our extended time series and subsequent analyses of the Ca ii H&K emission lines show that the host star has an activity cycle of ~13 years. …
X-Ray, Uv And Optical Analysis Of Supergiants: Ε Ori, R. E. Puebla, D. J. Hillier, J. Zsargó, David H. Cohen, M. A. Leutenegger
X-Ray, Uv And Optical Analysis Of Supergiants: Ε Ori, R. E. Puebla, D. J. Hillier, J. Zsargó, David H. Cohen, M. A. Leutenegger
Physics & Astronomy Faculty Works
We present a multi-wavelength (X-ray to optical) analysis, based on non-local thermodynamic equilibrium photospheric+wind models, of the B0 Ia-supergiant: ϵ Ori. The aim is to test the consistency of physical parameters, such as the mass-loss rate and CNO abundances, derived from different spectral bands. The derived mass-loss rate is M˙/f∞−−−√∼ 1.6 × 10−6 M⊙ yr−1 where f∞ is the volume filling factor. However, the S iv λλ1062,1073 profiles are too strong in the models; to fit the observed profiles it is necessary to use f∞ < 0.01. This value is a factor of 5 to 10 lower than inferred from other diagnostics, and implies M˙≲1×10−7 M⊙ yr−1. The discrepancy could be related to porosity–vorosity effects or a problem with the ionization of sulphur in the wind. To fit the UV profiles of N v and O vi it was necessary to include emission from an interclump medium with a density contrast (ρcl/ρICM) of ∼100. X-ray emission in H/He like and Fe L lines was modelled using four plasma components located within the wind. We derive plasma temperatures from 1 × 106 to 7 × 106 K, with lower temperatures starting in the outer regions (R0 ∼ 3–6 R*), and a hot component starting closer to the star (R0 ≲ 2.9 R*). From X-ray line profiles we infer M˙< 4.9 × 10−7 M⊙ yr−1. The X-ray spectrum (≥0.1 kev) yields an X-ray luminosity LX ∼ 2.0 × 10−7Lbol, consistent with the superion line profiles. X-ray abundances are in agreement with those derived from the UV and optical analysis: ϵ Ori is slightly enhanced in nitrogen and depleted in carbon and oxygen, evidence for CNO processed material.
The Mimes Survey Of Magnetism In Massive Stars: Introduction And Overview, G. A. Wade, C. Neiner, E. Alecian, J. H. Grunhut, V. Petit, B. De Batz, D. A. Bohlender, David H. Cohen, H. F. Heinrichs, O. Kochukhov, J. D. Landstreet, N. Manset, F. Martins, S. Mathis, M. E. Oksala, S. P. Owocki, T. Rivinius, M. E. Shultz, J. O. Sundqvist, R. H. D. Townsend, A. Ud-Doula, J.-C. Bouret, J. Braithwaite, M. Briquet, A. C. Carciofi, A. David-Uraz, C. P. Folsom, A. W. Fullerton, B. Leroy, W. L. F. Marcolino, A. F. J. Moffat, Y. Nazé, N. St Louis, M. Aurière, S. Bagnulo, J. D. Bailey, R. H. Barbá, A. Blazère, T. Böhm, C. Catala, J.-F. Donati, L. Ferrario, D. Harrington, I. D. Howarth, R. Ignace, L. Kaper, T. Lüftinger, R. Prinja, J. S. Vink, W. W. Weiss, I. Yakunin
The Mimes Survey Of Magnetism In Massive Stars: Introduction And Overview, G. A. Wade, C. Neiner, E. Alecian, J. H. Grunhut, V. Petit, B. De Batz, D. A. Bohlender, David H. Cohen, H. F. Heinrichs, O. Kochukhov, J. D. Landstreet, N. Manset, F. Martins, S. Mathis, M. E. Oksala, S. P. Owocki, T. Rivinius, M. E. Shultz, J. O. Sundqvist, R. H. D. Townsend, A. Ud-Doula, J.-C. Bouret, J. Braithwaite, M. Briquet, A. C. Carciofi, A. David-Uraz, C. P. Folsom, A. W. Fullerton, B. Leroy, W. L. F. Marcolino, A. F. J. Moffat, Y. Nazé, N. St Louis, M. Aurière, S. Bagnulo, J. D. Bailey, R. H. Barbá, A. Blazère, T. Böhm, C. Catala, J.-F. Donati, L. Ferrario, D. Harrington, I. D. Howarth, R. Ignace, L. Kaper, T. Lüftinger, R. Prinja, J. S. Vink, W. W. Weiss, I. Yakunin
Physics & Astronomy Faculty Works
The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O- and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada–France–Hawaii Telescope, Narval at the Télescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla 3.6 m …
Kelt-4ab: An Inflated Hot Jupiter Transiting The Bright (V~10) Component Of A Hierarchical Triple, J. D. Eastman, T. G. Beatty, R. J. Siverd, J. M. O. Antognini, M. T. Penny, E. J. Gonzales, J. R. Crepp, A. W. Howard, R. L. Avril, A. Bieryla, K. Collins, B. J. Fulton, J. Ge, J. Gregorio, B. Ma, S. N. Mellon, T. E. Oberst, J. Wang, B. S. Gaudi, J. Pepper, K. G. Stassun, L. A. Buchhave, Eric L. N. Jensen, D. W. Latham, P. Berlind, M. L. Calkins, P. A. Cargile, K. D. Colón, S. Dhital, G. A. Esquerdo, J. A. Johnson, J. F. Kielkopf, M. Manner, Q. Mao, K. K. Mcleod, K. Penev, R. P. Stefanik, R. Street, R. Zambelli, D. L. Depoy, A. Gould, J. L. Marshall, R. W. Pogge, M. Trueblood, P. Trueblood
Kelt-4ab: An Inflated Hot Jupiter Transiting The Bright (V~10) Component Of A Hierarchical Triple, J. D. Eastman, T. G. Beatty, R. J. Siverd, J. M. O. Antognini, M. T. Penny, E. J. Gonzales, J. R. Crepp, A. W. Howard, R. L. Avril, A. Bieryla, K. Collins, B. J. Fulton, J. Ge, J. Gregorio, B. Ma, S. N. Mellon, T. E. Oberst, J. Wang, B. S. Gaudi, J. Pepper, K. G. Stassun, L. A. Buchhave, Eric L. N. Jensen, D. W. Latham, P. Berlind, M. L. Calkins, P. A. Cargile, K. D. Colón, S. Dhital, G. A. Esquerdo, J. A. Johnson, J. F. Kielkopf, M. Manner, Q. Mao, K. K. Mcleod, K. Penev, R. P. Stefanik, R. Street, R. Zambelli, D. L. Depoy, A. Gould, J. L. Marshall, R. W. Pogge, M. Trueblood, P. Trueblood
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We report the discovery of KELT-4Ab, an inflated, transiting Hot Jupiter orbiting the brightest component of a hierarchical triple stellar system. The host star is an F star with ${T}_{{\rm{eff}}}$ = $6206\pm 75$ K, $\mathrm{log}g$ = $4.108\pm 0.014$, $[{\rm{Fe}}/{\rm{H}}]$ = $-{0.116}_{-0.069}^{+0.065}$, ${M}_{*}$ = ${1.201}_{-0.061}^{+0.067}$ $\;{M}_{\odot }$, and ${R}_{*}$ = ${1.603}_{-0.038}^{+0.039}$ $\;{R}_{\odot }$. The best-fit linear ephemeris is ${\mathrm{BJD}}_{\mathrm{TDB}}$ $\;=\;2456193.29157\pm 0.00021$ $\quad +\quad E(2.9895936\pm 0.0000048)$. With a magnitude of V ~ 10, a planetary radius of ${1.699}_{-0.045}^{+0.046}$ $\;{R}_{{\rm{J}}}$, and a mass of ${0.902}_{-0.059}^{+0.060}$ $\;{M}_{{\rm{J}}}$, it is the brightest host among the population of inflated Hot Jupiters (RP > 1.5RJ), making it a …
A Disk-Based Dynamical Constraint On The Mass Of The Young Binary Dq Tau, I. Czekala, S. M. Andrews, G. Torres, Eric L.N. Jensen, K. G. Stassun, D. J. Wilner, D. W. Latham
A Disk-Based Dynamical Constraint On The Mass Of The Young Binary Dq Tau, I. Czekala, S. M. Andrews, G. Torres, Eric L.N. Jensen, K. G. Stassun, D. J. Wilner, D. W. Latham
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We present new Atacama Large Millimeter/Submillimeter Array (ALMA) observations of CO J = 2-1 line emission from the DQ Tau circumbinary disk. These data are used to tomographically reconstruct the Keplerian disk velocity field in a forward-modeling inference framework, and thereby provide a dynamical constraint on the mass of the DQ Tau binary of {M}*={1.27}-0.27+0.46 {M}☉ . Those results are compared with an updated and improved orbital solution for this double-lined system based on long-term monitoring of its stellar radial velocities. Both of these independent dynamical constraints on the binary mass are in excellent agreement: …
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
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 …
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
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
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 …
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
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, …
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
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
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. …
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
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
Physics & Astronomy Faculty Works
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 MJ, radius {R}{{P}}={1.86}-0.16+0.18 RJ, surface gravity {log} {g} …
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
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
Physics & Astronomy Faculty Works
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 …
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
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
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 …
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
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
Physics & Astronomy Faculty Works
We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of 1.28+/- 0.18 MJ, radius of {1.533}-0.047+0.046 RJ, 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, Teff = 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 …
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
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 …
Measuring The Shock-Heating Rate In The Winds Of O Stars Using X-Ray Line Spectra, David H. Cohen, Zequn Li , '16, K. G. Gayley, S. P. Owocki, J. O. Sundqvist, V. Petit, M. A. Leutenegger
Measuring The Shock-Heating Rate In The Winds Of O Stars Using X-Ray Line Spectra, David H. Cohen, Zequn Li , '16, K. G. Gayley, S. P. Owocki, J. O. Sundqvist, V. Petit, M. A. Leutenegger
Physics & Astronomy Faculty Works
We present a new method for using measured X-ray emission line fluxes from O stars to determine the shock-heating rate due to instabilities in their radiation-driven winds. The high densities of these winds means that their embedded shocks quickly cool by local radiative emission, while cooling by expansion should be negligible. Ignoring for simplicity any non-radiative mixing or conductive cooling, the method presented here exploits the idea that the cooling post-shock plasma systematically passes through the temperature characteristic of distinct emission lines in the X-ray spectrum. In this way, the observed flux distribution among these X-ray lines can be used …
X-Ray Emission From Magnetic Massive Stars, Y. Nazé, V. Petit, M. Rinbrand, David H. Cohen, S. Owocki, A. Ud-Doula, G. A. Wade
X-Ray Emission From Magnetic Massive Stars, Y. Nazé, V. Petit, M. Rinbrand, David H. Cohen, S. Owocki, A. Ud-Doula, G. A. Wade
Physics & Astronomy Faculty Works
Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ~60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower-${\dot{M}}$ B stars and flattens for the …
X-Rays From Magnetically Confined Wind Shocks: Effect Of Cooling-Regulated Shock Retreat, A. Ud-Doula, S. Owocki, R. Townsend, V. Petit, David H. Cohen
X-Rays From Magnetically Confined Wind Shocks: Effect Of Cooling-Regulated Shock Retreat, A. Ud-Doula, S. Owocki, R. Townsend, V. Petit, David H. Cohen
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We use 2D magnetohydrodynamic (MHD) simulations to examine the effects of radiative cooling and inverse Compton (IC) cooling on X-ray emission from magnetically confined wind shocks (MCWS) in magnetic massive stars with radiatively driven stellar winds. For the standard dependence of mass-loss rate on luminosity Ṁ∼ L1.7, the scaling of IC cooling with L and radiative cooling with Ṁ means that IC cooling become formally more important for lower luminosity stars. However, because the sense of the trends is similar, we find the overall effect of including IC cooling is quite modest. More significantly, for stars with high enough mass-loss …
Misaligned Protoplanetary Disks In A Young Binary Star System, Eric L.N. Jensen, R. L. Akeson
Misaligned Protoplanetary Disks In A Young Binary Star System, Eric L.N. Jensen, R. L. Akeson
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Many extrasolar planets follow orbits that differ from the nearly coplanar and circular orbits found in our Solar System; their orbits may be eccentric or inclined with respect to the host star's equator, and the population of giant planets orbiting close to their host stars suggests appreciable orbital migration. There is at present no consensus on what produces such orbits. Theoretical explanations often invoke interactions with a binary companion star in an orbit that is inclined relative to the planet's orbital plane. Such mechanisms require significant mutual inclinations between the planetary and binary star orbital planes. The protoplanetary disks in …
Transit Timing Analysis In The Hat-P-32 System, M. Seeliger, D. Dimitrov, D. Kjurkchieva, M. Mallonn, M. Fernandez, M. Kitze, V. Casanova, G. Maciejewski, J. M. Ohlert, J. G. Schmidt, A. Pannicke, D. Puchalski, W. Göğüş, T. Güver, S. Bilir, T. Ak, M. M. Hohle, T. O. B. Schmidt, R. Errmann, Eric L.N. Jensen, David H. Cohen, L. Marschall, G. Saral, I. Bernt, E. Derman, C. Gałan, R. Neuhäuser
Transit Timing Analysis In The Hat-P-32 System, M. Seeliger, D. Dimitrov, D. Kjurkchieva, M. Mallonn, M. Fernandez, M. Kitze, V. Casanova, G. Maciejewski, J. M. Ohlert, J. G. Schmidt, A. Pannicke, D. Puchalski, W. Göğüş, T. Güver, S. Bilir, T. Ak, M. M. Hohle, T. O. B. Schmidt, R. Errmann, Eric L.N. Jensen, David H. Cohen, L. Marschall, G. Saral, I. Bernt, E. Derman, C. Gałan, R. Neuhäuser
Physics & Astronomy Faculty Works
We present the results of 45 transit observations obtained for the transiting exoplanet HAT-P-32b. The transits have been observed using several telescopes mainly throughout the YETI (Young Exoplanet Transit Initiative) network. In 25 cases, complete transit light curves with a timing precision better than 1.4 min have been obtained. These light curves have been used to refine the system properties, namely inclination i, planet-to-star radius ratio Rp/Rs, and the ratio between the semimajor axis and the stellar radius a/Rs. First analyses by Hartman et al. suggests the existence of a second planet in the system, thus we tried to find …
Measuring Mass-Loss Rates And Constraining Shock Physics Using X-Ray Line Profiles Of O Stars From The Chandra Archive, David H. Cohen, Emma E. Wollman , '09, M. A. Leutenegger, J. O. Sundqvist, A. W. Fullerton, J. Zsargó, S. P. Owocki
Measuring Mass-Loss Rates And Constraining Shock Physics Using X-Ray Line Profiles Of O Stars From The Chandra Archive, David H. Cohen, Emma E. Wollman , '09, M. A. Leutenegger, J. O. Sundqvist, A. W. Fullerton, J. Zsargó, S. P. Owocki
Physics & Astronomy Faculty Works
We quantitatively investigate the extent of wind absorption signatures in the X-ray grating spectra of all non-magnetic, effectively single O stars in the Chandra archive via line profile fitting. Under the usual assumption of a spherically symmetric wind with embedded shocks, we confirm previous claims that some objects show little or no wind absorption. However, many other objects do show asymmetric and blueshifted line profiles, indicative of wind absorption. For these stars, we are able to derive wind mass-loss rates from the ensemble of line profiles, and find values lower by an average factor of 3 than those predicted by …
Circumstellar Disks Around Binary Stars In Taurus, R. L. Akeson, Eric L.N. Jensen
Circumstellar Disks Around Binary Stars In Taurus, R. L. Akeson, Eric L.N. Jensen
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We have conducted a survey of 17 wide (〉100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10-4 M ☉. We compare the properties of our sample to the population of known disks …
Kelt-6b: A P ~ 7.9 Day Hot Saturn Transiting A Metal-Poor Star With A Long-Period Companion, K. A. Collins, J. D. Eastman, T. G. Beatty, R. J. Siverd, B. S. Gaudi, J. Pepper, J. F. Kielkopf, J. A. Johnson, A. W. Howard, D. A. Fischer, M. Manner, A. Bieryla, D. W. Latham, B. J. Fulton, J. Gregorio, L. A. Buchhave, Eric L.N. Jensen, K. G. Stassun, K. Penev, J. R. Crepp, S. Hinkley, R. A. Street, P. Cargile, C. E. Mack, T. E. Oberst, R. L. Avril, S. N. Mellon, K. K. Mcleod, M. T. Penny, R. P. Stefanik, P. Berlind, M. L. Calkins, Q. Mao, A. J.W. Richert, D. L. Depoy, G. A. Esquerdo, A. Gould, J. L. Marshall, R. J. Oelkers, R. W. Pogge, M. Trueblood, P. Trueblood
Kelt-6b: A P ~ 7.9 Day Hot Saturn Transiting A Metal-Poor Star With A Long-Period Companion, K. A. Collins, J. D. Eastman, T. G. Beatty, R. J. Siverd, B. S. Gaudi, J. Pepper, J. F. Kielkopf, J. A. Johnson, A. W. Howard, D. A. Fischer, M. Manner, A. Bieryla, D. W. Latham, B. J. Fulton, J. Gregorio, L. A. Buchhave, Eric L.N. Jensen, K. G. Stassun, K. Penev, J. R. Crepp, S. Hinkley, R. A. Street, P. Cargile, C. E. Mack, T. E. Oberst, R. L. Avril, S. N. Mellon, K. K. Mcleod, M. T. Penny, R. P. Stefanik, P. Berlind, M. L. Calkins, Q. Mao, A. J.W. Richert, D. L. Depoy, G. A. Esquerdo, A. Gould, J. L. Marshall, R. J. Oelkers, R. W. Pogge, M. Trueblood, P. Trueblood
Physics & Astronomy Faculty Works
We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T eff = 6102 ± 43 K, log g_\star =4.07_{-0.07}^{+0.04}, and [Fe/H] = -0.28 ± 0.04, with an inferred mass M sstarf = …