http://arxiv.org/abs/1901.02048
Several `Hot Jupiter’ host stars appear to exhibit enhanced chromospheric activity, coronal flaring, and starspot development synchronized to their planetary orbits. These effects have been attributed to tidal and/or magnetic interactions between the star and exoplanet. The best studied among such systems is HD 189733, which has previously been observed from radio to X-ray wavelengths. Here, I present ~4.75 GHz Arecibo radio telescope observations of HD 189733 during a fraction of the exoplanet orbital phase range previously associated with enhanced coronal X-ray flaring. No radio flares from the lower corona were detected. I also leverage MOST, APT, and Wise photometry to measure the occurences of minima associated with enhanced starspot activity. The phasing of these minima with the exoplanet orbit do not reveal any synchronized active region behavior. Moreover, for the first time, I combine X-ray, ultraviolet, photometric, Ca II H&K, H-alpha, and radio observations of HD 189733 to conduct an extensive, holistic re-examination of stellar activity in this system. Through the presentation of new data, and by merging physical and statistical analytic approaches, I demonstrate that the previously asserted enhancements in activity, allegedly synchronized to certain exoplanet orbital phases, are likely the result of inadequately-sampled intrinsic stellar activity from an active star, rather than star-planet interactions.
M. Route
Wed, 9 Jan 19
4/46
Comments: Accepted to ApJ; 29 pages, 2 figures, 5 tables