High-precision photometry by telescope defocussing - VIII. WASP-22, WASP-41, WASP-42 and WASP-55

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Southworth, John ; Tregloan-Reed, J. ; Andersen, M. I. ; Calchi Novati, S. ; Ciceri, S. ; Colque, J. P. ; D'Ago, G. ; Dominik, M. ; Evans, D. F. ; Gu, S.-H. ; Herrera-Cordova, A. ; Hinse, T. C. ; Jørgensen, Uffe Gråe ; Juncher, D. ; Kuffmeier, M. ; Mancini, L. ; Peixinho, N. ; Popovas, A. ; Rabus, M. ; Skottfelt, J. ; Rasmussen, René Tronsgaard ; Unda-Sanzana, E. ; Wang, X.-B. ; Wertz, O. ; Alsubai, K. A. ; Andersen, J. M. ; Bozza, V. ; Bramich, D. M. ; Burgdorf, M. ; Damerdji, Y. ... view all 50 authors (2016)
  • Publisher: Oxford University Press
  • Related identifiers: doi: 10.1093/mnras/stw279
  • Subject: Astrophysics - Solar and Stellar Astrophysics | QC Physics | individual: WASP-22 [stars] | WASP-41 | QB | QC | Astrophysics - Earth and Planetary Astrophysics | planetary systems | WASP-55 | WASP-42 | QB Astronomy | NDAS | fundamental parameters [stars]

J So acknowledges financial support from the Leverhulme Trust in the form of a Philip Leverhulme Prize. JTR acknowledges financial support from ORAU (Oak Ridge Associated Universities) and NASA in the form of a NASA Post-Doctoral Programme (NPP) Fellowship. DFE is funded by the UK's Science and Technology Facilities Council. EU-S acknowledges the support of CONICYT QUIMAL 130004 project. Funding for the Stellar Astrophysics Centre in Aarhus is provided by The Danish National Research Foundation (grant agreement no. DNRF106). The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement no. 267864). TCH acknowledges KASI research grants #2012-1-410-02, #2013-9-400-00, #2014-1-400-06 and #2015-1-850-04. NP acknowledges funding by the Gemini-Conicyt Fund, allocated to project no. 32120036. GD acknowledges Regione Campania for support from POR-FSE Campania 2014–2020. YD, AE, OW and J Su acknowledge support from the Communauté française de Belgique - Actions de recherche concertées - Académie Wallonie-Europe. We present 13 high-precision and four additional light curves of four bright southern-hemisphere transiting planetary systems: WASP-22, WASP-41, WASP-42 and WASP-55. In the cases of WASP-42 and WASP-55, these are the first follow-up observations since their discovery papers. We present refined measurements of the physical properties and orbital ephemerides of all four systems. No indications of transit timing variations were seen. All four planets have radii inflated above those expected from theoretical models of gas-giant planets; WASP-55 b is the most discrepant with a mass of 0.63 MJup and a radius of 1.34 RJup. WASP-41 shows brightness anomalies during transit due to the planet occulting spots on the stellar surface. Two anomalies observed 3.1 d apart are very likely due to the same spot. We measure its change in position and determine a rotation period for the host star of 18.6 ± 1.5 d, in good agreement with a published measurement from spot-induced brightness modulation, and a sky-projected orbital obliquity of λ = 6 ± 11°. We conclude with a compilation of obliquity measurements from spot-tracking analyses and a discussion of this technique in the study of the orbital configurations of hot Jupiters. Publisher PDF Peer reviewed
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