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Register a new userHAT-P-7b: An Extremely Hot Massive Planet Transiting a Bright Star in the Kepler Field
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We report on the latest discovery of the HATNet project; a very hot giant planet orbiting a bright (V = 10.5) star with a small semi-major axis of a = 0.0377 +/- 0.0005 AU. Ephemeris for the system is P = 2.2047299 +/- 0.0000040 days, mid-transit time E = 2,453,790.2593 +/- 0.0010 (BJD). Based on the available spectroscopic data on the host star and photometry of the system, the planet has a mass of Mp = 1.78+/-^{0.08}_{0.05} MJup and radius of Rp = 1.36+/-^{0.20}_{0.09} RJup. The parent star is a slightly evolved F6 star with M = 1.47+/-^{0.08}_{-0.05} Msun,R = 1.84+/-^{0.23}_{0.11} Rsun, Teff = 6350 +/- 80 K, and metallicity [Fe/H] = +0.26 +/- 0.08. The relatively hot and large host star, combined with the close orbit of the planet, yield a very high planetary irradiance of (4.71+/-^{1.44}_{0.05}) 10^9 erg cm^{-2}s^{-1}, which places the planet near the top of the pM class of irradiated planets as defined by Fortney et al. (2007). If as predicted by Fortney et al. (2007) the planet re-radiates its absorbed energy before distributing it to the night side, the day-side temperature should be about (2730+/-^{150}_{100}) K. Because the host star is quite bright, measurement of the secondary eclipse should be feasible for ground-based telescopes, providing a good opportunity to compare the predictions of current hot Jupiter atmospheric models with the observations. Moreover, the host star falls in the field of the upcoming Kepler mission; hence extensive space-borne follow-up, including not only primary transit and secondary eclipse observations but also asteroseismology, will be possible.
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We report on the discovery of HAT-P-11b, the smallest radius transiting extrasolar planet (TEP) discovered from the ground, and the first hot Neptune discovered to date by transit searches. HAT-P-11b orbits the bright (V=9.587) and metal rich ([Fe=H] = +0.31 +/- 0.05) K4 dwarf star GSC 03561-02092 with P = 4.8878162 +/- 0.0000071 days and produces a transit signal with depth of 4.2 mmag. We present a global analysis of the available photometric and radial-velocity data that result in stellar and planetary parameters, with simultaneous treatment of systematic variations. The planet, like its near-twin GJ 436b, is somewhat larger than Neptune (17Mearth, 3.8Rearth) both in mass Mp = 0.081 +/- 0.009 MJ (25.8 +/- 2.9 Mearth) and radius Rp = 0.422 +/- 0.014 RJ (4.73 +/- 0.16 Rearth). HAT-P-11b orbits in an eccentric orbit with e = 0.198 +/- 0.046 and omega = 355.2 +/- 17.3, causing a reflex motion of its parent star with amplitude 11.6 +/- 1.2 m/s, a challenging detection due to the high level of chromospheric activity of the parent star. Our ephemeris for the transit events is Tc = 2454605.89132 +/- 0.00032 (BJD), with duration 0.0957 +/- 0.0012 d, and secondary eclipse epoch of 2454608.96 +/- 0.15 d (BJD). The basic stellar parameters of the host star are M* = 0.809+0.020-0.027 Msun, R* = 0.752 +/- 0.021 Rsun and Teff = 4780 +/- 50 K. Importantly, HAT-P-11 will lie on one of the detectors of the forthcoming Kepler mission. We discuss an interesting constraint on the eccentricity of the system by the transit light curve and stellar parameters. We also present a blend analysis, that for the first time treats the case of a blended transiting hot Jupiter mimicing a transiting hot Neptune, and proves that HAT-P-11b is not such a blend.
In the ongoing HATNet survey we have detected a giant planet, with radius 1.33 +/- 0.06 RJup and mass 1.06 +/- 0.12 MJup, transiting the bright (V = 10.5) star GSC 03239-00992. The planet is in a circular orbit with period 3.852985 +/- 0.000005 days and mid-transit epoch 2,454,035.67575 +/- 0.00028 (HJD). The parent star is a late F star with mass 1.29 +/- 0.06 Msun, radius 1.46 +/- 0.06 Rsun, Teff ~ 6570 +/- 80 K, [Fe=H] = -0.13 +/- 0.08 and age ~ 2.3+/-^{0.5}_{0.7}Gy. With this radius and mass, HAT-P-6b has somewhat larger radius than theoretically expected. We describe the observations and their analysis to determine physical properties of the HAT-P-6 system, and briefly discuss some implications of this finding.
We report the discovery of a planet transiting a moderately bright (V = 12.00) G star, with an orbital period of 2.788491 +/-0.000025 days. From the transit light curve we determine that the radius of the planet is Rp = 1.257 +/- 0.053 RJup. HAT-P-5b has a mass of Mp = 1.06 +/- 0.11 MJup, similar to the average mass of previously-known transiting exoplanets, and a density of rho = 0.66 +/- 0.11 g cm^-3 . We find that the center of transit is Tc = 2,454,241.77663 +/- 0.00022 (HJD), and the total transit duration is 0.1217 +/- 0.0012 days.
We report the discovery of HAT-P-16b, a transiting extrasolar planet orbiting the V = 10.8 mag F8 dwarf GSC 2792-01700, with a period P = 2.775960 +- 0.000003 d, transit epoch Tc = 2455027.59293 +- 0.00031 (BJD), and transit duration 0.1276 +- 0.0013 d. The host star has a mass of 1.22 +- 0.04 Msun, radius of 1.24 +- 0.05 Rsun, effective temperature 6158 +-80 K, and metallicity [Fe/H] = +0.17 +- 0.08. The planetary companion has a mass of 4.193 +- 0.094 MJ, and radius of 1.289 +- 0.066 RJ yielding a mean density of 2.42 +- 0.35 g/cm3. Comparing these observed characteristics with recent theoretical models, we find that HAT-P-16b is consistent with a 1 Gyr H/He-dominated gas giant planet. HAT-P-16b resides in a sparsely populated region of the mass{radius diagram and has a non-zero eccentricity of e = 0.036 with a significance of 10 sigma.
We report the discovery of the transiting extrasolar planet HAT-P-49b. The planet transits the bright (V = 10.3) slightly evolved F-star HD 340099 with a mass of 1.54M_S and a radius of 1.83 R_S. HAT-P-49b is orbiting one of the 25 brightest stars to host a transiting planet which makes this a favorable candidate for detailed follow-up. This system is an especially strong target for Rossiter- McLaughlin follow-up due to the fast rotation of the host star, 16 km/s. The planetary companion has a period of 2.6915 d, mass of 1.73 M_J and radius of 1.41 R_J. The planetary characteristics are consistent with that of a classical hot Jupiter but we note that this is the fourth most massive star to host a transiting planet with both M_p and R_p well determined.
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