Document Type
Article
Publication Date
2-10-2016
Abstract
We present 13 high-precision and four additional light curves of four bright southernhemisphere 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 0.63MJup 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.
Publication Source (Journal or Book title)
Monthly Notices of the Royal Astronomical Society
First Page
4205
Last Page
4217
Recommended Citation
Southworth, J., Tregloan-Reed, J., Andersen, M., Calchi Novati, S., Ciceri, S., Colque, J., D'Ago, G., Dominik, M., Evans, D., Gu, S., Herrera-Cordova, A., Hinse, T., Jørgensen, U., Juncher, D., Kuffmeier, M., Mancini, L., Peixinho, N., Popovas, A., Rabus, M., Skottfelt, J., Tronsgaard, R., Unda-Sanzana, E., Wang, X., Wertz, O., Alsubai, K., Andersen, J., Bozza, V., Bramich, D., Burgdorf, M., Damerdji, Y., Diehl, C., Elyiv, A., & Figuera Jaimes, R. (2016). High-precision photometry by telescope defocussing - VIII.WASP-22, WASP-41,WASP-42 andWASP-55. Monthly Notices of the Royal Astronomical Society, 457 (4), 4205-4217. https://doi.org/10.1093/mnras/stw279