* Astronomy

Title: HAT-P-30b: A transiting hot Jupiter on a highly oblique orbit
Authors: John Asher Johnson, J. N. Winn, J. D. Hartman, G. A. Bakos, T. D. Morton, G. Torres, Géza Kovács, D. W. Latham, R. W. Noyes, B. Sato, G. A. Esquerdo, D. A. Fischer, G. W. Marcy, A. W. Howard, S. N. Quinn, B. Beky, D. D. Sasselov, R. P. Stefanik, J. Lazar, I. Papp, P. Sari, L. A. Buchhave, G. Furesz

We report the discovery of HAT-P-30b, a transiting exoplanet orbiting the V=10.419 dwarf star GSC 0208-00722. The planet has a period P=2.810595±0.000005 d, transit epoch Tc = 2455456.46561±0.00037 (BJD), and transit duration 0.0887±0.0015 d. The host star has a mass of 1.24±0.04 Msun, radius of 1.21±0.05 Rsun, effective temperature 6304±88 K, and metallicity [Fe/H] = +0.13±0.08. The planetary companion has a mass of 0.711±0.028 Mjup, and radius of 1.340±0.065 Rjup yielding a mean density of 0.37±0.05 g cm^-3. We also present radial velocity measurements that were obtained throughout a transit that exhibit the Rossiter-McLaughlin effect. By modelling this effect we measure an angle of \lambda = 73.5±9.0 deg between the sky projections of the planet's orbit normal and the star's spin axis. HAT-P-30b represents another example of a close-in planet on a highly tilted orbit, and conforms to the previously noted pattern that tilted orbits are more common around stars with Teff > 6250 K.

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