Barros, S. C. C.; Faedi, F.; Collier Cameron, A.; Lister, T. A.; McCormac, J.; Pollacco, D.; Simpson, E. K.; Smalley, B.; Street, R. A.; Todd, I.; Triaud, A. H. M. J.; Boisse, I.; Bouchy, F.; Hébrard, G.; Moutou, C.; Pepe, F.; Queloz, D.; Santerne, A.; Segransan, D.; Udry, S.; Bento, J.; Butters, O. W.; Enoch, B.; Haswell, C. A.; Hellier, C.; Keenan, F. P.; Miller, G. R. M.; Moulds, V.; Norton, A. J.; Parley, N.; Skillen, I.; Watson, C. A.; West, R. G. and Wheatley, P. J.
WASP-38b: a transiting exoplanet in an eccentric, 6.87d period orbit.
Astronomy and Astrophysics, 525
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Aims: We report the discovery of WASP-38b, a long period transiting planet in an eccentric 6.871815 day orbit. The transit epoch is 2 455 335.92050 ± 0.00074 (HJD) and the transit duration is 4.663 h.
Methods: WASP-38b's discovery was enabled due to an upgrade to the SuperWASP-North cameras. We performed a spectral analysis of the host star HD 146389/BD+10 2980 that yielded Teff = 6150 ± 80 K, log g = 4.3 ± 0.1, v sin i = 8.6 ± 0.4 km s-1, M* = 1.16 ± 0.04 Mʘand R* = 1.33 ± 0.03 Rʘ, consistent with a dwarf of spectral type F8. Assuming a main-sequence mass-radius relation for the star, we fitted simultaneously the radial velocity variations and the transit light curves to estimate the orbital and planetary parameters.
Results: The planet has a mass of 2.69 ± 0.06 MJup and a radius of 1.09 ± 0.03 RJup giving a density, ρp = 2.1 ± 0.1 ρJ. The high precision of the eccentricity e = 0.0314 ± 0.0044 is due to the relative transit timing from the light curves and the RV shape. The planet equilibrium temperature is estimated at 1292 ± 33 K. WASP-38b is the longest period planet found by SuperWASP-North and with a bright host star (V = 9.4 mag), is a good candidate for followup atmospheric studies.
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