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; the shallowest found by transit searches that is due to a confirmed planet. 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 (17M ⊕ , 3.8R ⊕ ) both in mass M p = 0.081 ± 0.009 M J (25.8 ± 2.9 M ⊕ ) and radius R p = 0.422 ± 0.014 R J (4.73 ± 0.16 R ⊕ ). HAT-P-11b orbits in an eccentric orbit with e = 0.198 ± 0.046 and ω = 355.2 ± 17.3 • , causing a reflex motion of its parent star with amplitude 11.6 ± 1.2 m s −1 , a challenging detection due to the high level of chromospheric activity of the parent star. Our ephemeris for the transit events is T c = 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 M ⊙ , R ⋆ = 0.752 ± 0.021 R ⊙ and T eff⋆ = 4780 ± 50 K. Importantly, HAT-P-11 will lie on one of the detectors of the forthcoming Kepler mission; this should make possible fruitful investigations of the detailed physical characteristic of both the planet and its parent star at unprecedented precision. We discuss an interesting constraint on the eccentricity of the system by the transit light curve and stellar parameters. This will be particularly useful for eccentric TEPs with low amplitude RV variations in Kepler's field. 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.

We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains the largest number of homogeneously observed and reduced nearby SNe Ia (z 0.08) published to date. It more than doubles the nearby sample, bringing SN Ia cosmology to the point where systematic uncertainties dominate. Our natural system photometry has a precision of 0.02 mag in BV RI r i and 0.04 mag in U for points brighter than 17.5 mag. We also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system BV RI r i photometry and 0.07 mag for U. Comparisons of our standard system photometry with published SN Ia light curves and comparison stars, where available for the same SN, reveal agreement at the level of a few hundredths mag in most cases. We find that 1991bg-like SNe Ia are sufficiently distinct from other SNe Ia in their color and light-curve-shape/ luminosity relation that they should be treated separately in light-curve/distance fitter training samples. The CfA3 sample will contribute to the development of better light-curve/distance fitters, particularly in the few dozen cases where near-infrared photometry has been obtained and, together, can help disentangle host-galaxy reddening from intrinsic supernova color, reducing the systematic uncertainty in SN Ia distances due to dust.

We report the discovery of a massive ( M p ¼ 9:04 AE 0:50 M J ) planet transiting the bright (V ¼ 8:7) F8 star HD 147506, with an orbital period of 5:63341 AE 0:00013 days and an eccentricity of e ¼ 0:520 AE 0:010. From the transit light curve we determine that the radius of the planet is R p ¼ 0:982 þ0:038 À0:105 R J . HD 147506b (also coined HAT-P-2b) has a mass about 9 times the average mass of previously known transiting exoplanets and a density of p % 12 g cm À3 , greater than that of rocky planets like the Earth. Its mass and radius are marginally consistent with theories of structure of massive giant planets composed of pure H and He, and accounting for them may require a large (k100 M È ) core. The high eccentricity causes a ninefold variation of insolation of the planet between peri-and apastron. Using follow-up photometry, we find that the center of transit is T mid ¼ 2;454;212:8559 AE 0:0007 ( HJD) and the transit duration is 0:177 AE 0:002 days.

We report new spectroscopic and photometric observations of the parent stars of the recently discovered transiting planets TrES-3 and TrES-4. A detailed abundance analysis based on high-resolution spectra yields [Fe/H] = −0.19 ± 0.08, T eff = 5650 ± 75 K, and log g = 4.4 ± 0.1 for TrES-3, and [Fe/H] = +0.14 ± 0.09, T eff = 6200 ± 75 K, and log g = 4.0±0.1 for TrES-4. The accuracy of the effective temperatures is supported by a number of independent consistency checks. The spectroscopic orbital solution for TrES-3 is improved with our new radial-velocity measurements of that system, as are the light-curve parameters for both systems based on newly acquired photometry for TrES-3 and a reanalysis of existing photometry for TrES-4. We have redetermined the stellar parameters taking advantage of the strong constraint provided by the light curves in the form of the normalized separation a/R ⋆ (related to the stellar density) in conjunction -2with our new temperatures and metallicities. The masses and radii we derive are M ⋆ = 0.928 +0.028 −0.048 M ⊙ , R ⋆ = 0.829 +0.015 −0.022 R ⊙ , and M ⋆ = 1.404 +0.066 −0.134 M ⊙ , R ⋆ = 1.846 +0.096 −0.087 R ⊙ for TrES-3 and TrES-4, respectively. With these revised stellar parameters we obtain improved values for the planetary masses and radii. We find M p = 1.910 +0.075 −0.080 M Jup , R p = 1.336 +0.031 −0.036 R Jup for TrES-3, and M p = 0.925 ± 0.082 M Jup , R p = 1.783 +0.093 −0.086 R Jup for TrES-4. We confirm TrES-4 as the planet with the largest radius among the currently known transiting hot Jupiters.

We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V=11.289 late-F-early-G dwarf star GSC 3281-00800, with a period P = 2.150008 ± 0.000001 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 (∼ 80 m s −1 ). Assuming a circular orbit, the star has a mass of 1.16 ± 0.04 M ⊙ , and radius of 1.22 ± 0.02 R ⊙ , while the planet has a mass of 0.860 ± 0.164 M J , and a radius of 1.789 ± 0.025 R J . When the eccentricity is allowed to vary, the best-fit model has e = 0.177 ± 0.079 and results in a planet which is close to filling its Roche Lobe. We determine an analytic approximation for the transit-inferred radius of an eccentric planet which fills 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, M p = 0.94 ± 0.17 M J , R p = 2.04 ± 0.10 R J , M ⋆ = 1.18 +0.04 −0.07 M ⊙ and R ⋆ = 1.39 ± 0.07 R ⊙ . The second planet, HAT-P-33b, orbits the bright V=11.188 late-F dwarf star GSC 2461-00988, with a period P = 3.474474 ± 0.000001 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 (∼ 50 m s −1 ). In this case spectral line bisector spans are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ∼ 35 m s −1 . We find the star has a mass of either 1.38 ± 0.04 M ⊙ or 1.40 ± 0.10 M ⊙ , and a radius of either 1.64 ± 0.03 R ⊙ or 1.78 ± 0.28 R ⊙ , while the planet has a mass of either 0.762 ± 0.101 M J or 0.763 ± 0.117 M J , and a radius of either 1.686 ± 0.045 R J or 1.827 ± 0.290 R J , 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 modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date.