Pulsation analysis and its impact on primary transit modeling in WASP-33

Abstract

To date, WASP-33 is the only delta Scuti star known to be orbited by a hot Jupiter. The pronounced stellar pulsations, showing periods comparable to the primary transit duration, interfere with the transit modeling. Therefore our main goal is to study the pulsation spectrum of the host star to redetermine the orbital parameters of the system by means of pulsation-cleaned primary transit light curves. Between August 2010 and October 2012 we obtained 457 hours of photometry of WASP-33 using small and middle-class telescopes located mostly in Spain and in Germany. Our observations comprise the wavelength range between the blue and the red, and provide full phase coverage of the planetary orbit. After a careful detrend, we focus our pulsation studies in the high frequency regime, where the pulsations that mostly deform the primary transit exist. The data allow us to identify, for the first time in the system, eight significant pulsation frequencies. The pulsations are likely associated with low-order p-modes. Furthermore, we find that pulsation phases evolve in time. We use our knowledge of the pulsations to clean the primary transit light curves and carry out an improved transit modeling. Surprisingly, taking into account the pulsations in the modeling has little influence on the derived orbital parameters. However, the uncertainties in the best-fit parameters decrease. Additionally, we find indications for a possible dependence between wavelength and transit depth, but only with marginal significance. A clear pulsation solution, in combination with an accurate orbital period, allows us to extend our studies and search for star-planet interactions (SPI). Although we find no conclusive evidence of SPI, we believe that the pulsation nature of the host star and the proximity between members make WASP-33 a promising system for further SPI studies.

19 pages, 11 figures, paper accepted

References in corpus (6)

• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• The effect of red noise on planetary transit detection
• KIC 4544587: an Eccentric, Short Period Binary System with delta Sct Pulsations and Tidally Excited Modes
• Improved parameters for the transiting hot Jupiters WASP-4b and WASP-5b
• Comprehensive time series analysis of the transiting extrasolar planet WASP-33b
• The GROUSE project III: Ks-band observations of the thermal emission from WASP-33b

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