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TOPIC: HAT-P-32b

Blobrana

L

Posts: 131433

Date: Apr 28 09:52 2014

HAT-P-32	Permalink

Title: Transit Timing Analysis in the HAT-P-32 system Author: 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, E. Gogus, T. Güver, S. Bilir, T. Ak, M. M. Hohle, T. O. B. Schmidt, R. Errmann, E. Jensen, D. Cohen, L. Marschall, G. Saral, I. Bernt, E. Derman, C. Galan, R. Neuhäuser 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 network. In 25 cases, complete transit light curves with a timing precision better than 1.4min 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. (2011) suggest the existence of a second planet in the system, thus we tried to find an additional body using the transit timing variation (TTV) technique. Taking also literature data points into account, we can explain all mid-transit times by refining the linear ephemeris by 21ms. Thus we can exclude TTV amplitudes of more than ~1.5min. Read more (844kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 8 01:15 2011

HAT-P-32b	Permalink

Title: HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-Jitter Stars Authors: J. D. Hartman, G. Á. Bakos, G. Torres, D. W. Latham, G. Kovács, B. Béky, S. N. Quinn, T. Mazeh, A. Shporer, G. W. Marcy, A. W. Howard, D. A. Fischer, J. A. Johnson, G. A. Esquerdo, R. W. Noyes, D. D. Sasselov, R. P. Stefanik, J. M. Fernandez, T. Szklenár, J. Lázár, I. Papp, P. Sári We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V=11.289 star GSC 3281-00800, with a period P = 2.150008 d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high velocity jitter (~80m/s). Assuming a circular orbit, the star has a mass of 1.16±0.04 M_sun, and radius of 1.22±0.02 R_sun, while the planet has a mass of 0.860±0.164 MJ, and a radius of 1.789±0.025 RJ. When the eccentricity is allowed to vary, the best-fit model results in a planet which is close to filling its Roche Lobe. Including the constraint that the planet cannot exceed its Roche Lobe results in the following best-fit parameters: e = 0.163±0.061, Mp = 0.94±0.17 MJ, Rp = 2.04±0.10 RJ, Ms = 1.18+0.04-0.07 M_sun and Rs = 1.39±0.07 R_sun. The second planet, HAT-P-33b, orbits the bright V=11.188 star GSC 2461-00988, with a period P = 3.474474 d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter (~50m/s). In this case spectral line bisector spans are significantly anti-correlated with the radial velocity residuals, and we use this correlation to reduce the residual rms to ~35m/s. We find the star has a mass of either 1.38±0.04 M_sun or 1.40±0.10 M_sun, and a radius of either 1.64±0.03 R_sun or 1.78±0.28 R_sun, while the planet has a mass of either 0.762±0.101 MJ or 0.763±0.117 MJ, and a radius of either 1.686±0.045 RJ or 1.827±0.290 RJ, for an assumed circular orbit or for the best-fit eccentric orbit respectively. Due to the large bisector span variations exhibited by both stars we rely on detailed modelling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date. Read more (711kb, PDF) __________________

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