Orbital alignment and star-spot properties in the WASP-52 planetary system
Abstract
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.
Citation
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 . https://doi.org/10.1093/mnras/stw1987
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
ISSN
0035-8711Type
Journal article
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