Exoplanet Studies. Photometric Analysis of the Transmission Spectra of Selected Exoplanets

摘要

We present the results of ground based observations and model analysis of transits of exoplanets WASP-33b, WASP-43b, WASP-104b, and HD 219134b. Broadband transmission spectra (dependence of the observed radii on wavelength) have been plotted for all exoplanets, ranging from the near-UV to the IR region. We show that the transmission spectrum of WASP-33b is, within errors, flat in the range of 3800 to 12 000 . The derived broadband spectrum of WASP-43b is also flat in the first approximation, although other authors have reported the presence of absorption lines of various chemical elements in the narrow bands. Model spectra of WASP-43b taken from the literature and based on IR data allowed us to obtain a direct estimate of its nighttime temperature. We present and analyze the results of ground based observations which confirm the discovery of a transiting super-Earth in the HD 219134 star system. Signs of this planet's existence were discovered earlier during the radial velocity analysis of the star, as well as transit observations with the Spitzer space telescope in the IR.At the estimated time, we registered a transit in the near-UV range several times. The transit depth measured in the U-band of the Johnson photometric system amounts to 0.13% +/- 0.027%, which is deeper than the one based on Spitzer measurements. We discuss the possible causes of this difference.