WASP-38b: A Transiting Exoplanet in an Eccentric, 6.87d Period Orbit

S. C. C. Barros; F. Faedi; A. Collier Cameron; T. A. Lister; J. McCormac; D. Pollacco; E. K. Simpson; B. Smalley; R. A. Street; I. Todd; A. H. M. J. Triaud; I. Boisse; F. Bouchy; G. Hebrard; C. Moutou; F. Pepe; D. Queloz; A. Santerne; D. Segransan; S. Udry; J. Bento; O. W. Butters; B. Enoch; C. A. Haswell; C. Hellier; F. P. Keenan; G. R. M. Miller; V. Moulds; A. J. Norton; N. Parley; I. Skillen; C. A. Watson; R. G. West; P. J. Wheatley

doi:10.1051/0004-6361/201015800

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arXiv · 1010.0849

WASP-38b: A Transiting Exoplanet in an Eccentric, 6.87d Period Orbit

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Abstract

We report the discovery of WASP-38b, a long period transiting planet in an eccentric 6.871815 day orbit. The transit epoch is 2455335.92050 +/- 0.00074 (HJD) and the transit duration is 4.663 hours. 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 +/- 80K, logg =4.3 +/- 0.1, vsini=8.6 +/- 0.4 km/s, M*=1.16 +/- 0.04 Msun and R* =1.33 +/- 0.03 Rsun, 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. The planet has a mass of 2.69 +/- 0.06 Mjup and a radius of 1.09 +/-0.03 Rjup giving a density, rho_p = 2.1 +/-0.1 rho_jup. 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 +/- 33K. 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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S. C. C. Barros, F. Faedi, A. Collier Cameron, T. A. Lister, J. McCormac, D. Pollacco, E. K. Simpson, B. Smalley, R. A. Street, I. Todd, A. H. M. J. Triaud, I. Boisse, F. Bouchy, G. Hebrard, C. Moutou, F. Pepe, D. Queloz, A. Santerne, D. Segransan, S. Udry, J. Bento, O. W. Butters, B. Enoch, C. A. Haswell, C. Hellier, F. P. Keenan, G. R. M. Miller, V. Moulds, A. J. Norton, N. Parley, I. Skillen, C. A. Watson, R. G. West, P. J. Wheatley. 2010-10-05. WASP-38b: A Transiting Exoplanet in an Eccentric, 6.87d Period Orbit. https://doi.org/10.1051/0004-6361/201015800

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