KELT-8b: A highly inflated transiting hot Jupiter and a new technique for extracting high-precision radial velocities from noisy spectra

We announce the discovery of a highly inflated transiting hot Jupiter discovered 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 $T_{\rm eff} = 5754_{-55}^{+54}$ K, $\log{g} = 4.078_{-0.054}^{+0.049}$, $[Fe/H] = 0.272\pm0.038$, an inferred mass $M_{*}=1.211_{-0.066}^{+0.078}$ M$_{\odot}$, and radius $R_{*}=1.67_{-0.12}^{+0.14}$ R$_{\odot}$. The planetary companion has mass $M_P = 0.867_{-0.061}^{+0.065}$ $M_{J}$, radius $R_P = 1.86_{-0.16}^{+0.18}$ $R_{J}$, surface gravity $\log{g_{P}} = 2.793_{-0.075}^{+0.072}$, and density $\rho_P = 0.167_{-0.038}^{+0.047}$ g cm$^{-3}$. The planet is on a roughly circular orbit with semimajor axis $a = 0.04571_{-0.00084}^{+0.00096}$ AU and eccentricity $e = 0.035_{-0.025}^{+0.050}$. The best-fit linear ephemeris is $T_0 = 2456883.4803 \pm 0.0007$ BJD$_{\rm TDB}$ and $P = 3.24406 \pm 0.00016$ days. This planet is one of the most inflated of all known transiting exoplanets, making it one of the few members of a class of extremely low density, highly-irradiated gas giants. The low stellar $\log{g}$ and large implied radius are supported by stellar density constraints from follow-up light curves, plus an evolutionary and space motion analysis. We also develop a new technique to extract high precision radial velocities from noisy spectra that reduces the observing time needed to confirm transiting planet candidates. This planet boasts deep transits of a bright star, a large inferred atmospheric scale height, and a high equilibrium temperature of $T_{eq}=1675^{+61}_{-55}$ K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.Comment: Submitted to ApJ, feedback is welcom

MINIMA OF ECLIPSING BINARIES AND NEW EPHEMERIDES FOR GSC 03881-00579 AND EZ LACERTAE

The list below contains 163 times of minimum for 79 eclipsing binary stars (including the cataclysmic AM Her) calculated from CCD observations made by participants in the SSV-UAI Eclipsing Binaries Program. All the observatories are located in Italy; one is managed by the Physics Department of the University of Siena, while the others are privately operated. Some light curves were remotely obtained (via Internet) using the Italian and Australian telescopes of the Skylive-UAI Project, that are publicly available on the web site http://www.skylive.it. The observations were reduced following standard procedures (see next section) and the light curves were analyzed using the Kwee−van Woerden algorithm (Kwee & van Woerden,1956) to determine the times of minimum. All the times of minimum listed in this paper are heliocentric ones. It is worth noting that most of the observed stars are neglected objects.New ephemeris are given for GSC 03881-00579 and EZ La

Minima of eclipsing binary stars

We present several CCD minima observations of eclipsing binaries

KELT-20b: A Giant Planet with a Period of P ∼ 3.5 days Transiting the V ∼ 7.6 Early A Star HD 185603

We report the discovery of KELT-20b, a hot Jupiter transiting a V ∼7.6 early A star, HD 185603, with an orbital period of P ≃3.47 days. Archival and follow-up photometry, Gaia parallax, radial velocities, Doppler tomography, and AO imaging were used to confirm the planetary nature of KELT-20b and characterize the system. From global modeling we infer that KELT-20 is a rapidly rotating (v sin I∗ ≃ 120 km s-1 ) A2V star with an effective temperature of Teff=8730 -260 +250 K, mass of M∗+1.76-0.20 +0.14MO, radius of R∗= 1.561-0.064+0.058RO,surface gravity of log g ∗=4.292-0.020+0.017, and age of ≳600 Myr. The planetary companion has a radius of Rp=1.735 -0.075 +0.070Rj, a semimajor axis of a =0.0542-0.0021+0.0014 au, and a linear ephemeris of BJDTDB=2457503.120049 ± 0.000190+E(3.4741070± 0.0000019). We place a 3s upper limit of ∼ 3.5 MJ on the mass of the planet. Doppler tomographic measurements indicate that the planetary orbit normal is well aligned with the projected spin axis of the star (l = 3 °.4± 2 °.1). The inclination of the star is constrained to 24°.4 > I ∗ > 155 °.6, implying a three-dimensional spin-orbit alignment of 1°.3 > ψ > 69°.8. KELT-20b receives an insolation flux of∼8× 109 erg s-1cm-2, implying an equilibrium temperature of of ∼ 2250 K, assuming zero albedo and complete heat redistribution. Due to the high stellar Teff, KELT-20b also receives an ultraviolet (wavelength d ≤ 91.2 nm) insolation flux of ∼9.1×104erg s-1 cm-2, possibly indicating significant atmospheric ablation. Together with WASP-33, Kepler-13 A, HAT-P-57, KELT-17, and KELT-9, KELT-20 is the sixth A star host of a transiting giant planet, and the third brightest host (in V) of a transiting planet