Orbital alignment and star-spot properties in the WASP-52 planetary system
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We report 13 high-precision light curves of eight transits of the exoplanet WASP-52b, obtained by using four medium-class telescopes,through different filters, and adopting the defocussing technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments,including a multi-band camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the jktebop code,and those with the anomalies with the prism+gemc codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 days. In the hypothesis that we are dealing with the same stars-pot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52b to be λ = 3.°8 ± 8.°4. We also determined the true orbital obliquity, ψ = 20° ± 50°, which is, although very uncertain, the first measurement of ψ purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties.
Mancini , L , Southworth , J , Raia , G , Tregloan-Reed , J , Mollière , P , Bozza , V , Bretton , M , Bruni , I , Ciceri , S , D'Ago , G , Dominik , M , Hinse , T C , Hundertmark , M , Jørgensen , U G , Korhonen , H , Rabus , M , Rahvar , S , Starkey , D , Calchi Novati , S , Figuera Jaimes , R , Henning , T , Juncher , D , Haugbølle , T , Kains , N , Popovas , A , Schmidt , R W , Skottfelt , J , Snodgrass , C , Surdej , J & Wertz , O 2017 , ' Orbital alignment and star-spot properties in the WASP-52 planetary system ' Monthly Notices of the Royal Astronomical Society , vol 465 , no. 1 , pp. 843-857 . DOI: 10.1093/mnras/stw1987
Monthly Notices of the Royal Astronomical Society
© 2017, the Author(s). This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at academic.oup.com/mnras / https://doi.org/10.1093/mnras/stw1987
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