| 其他摘要 | To date, more than 4900 exoplanets have been discovered, including more than 3500 transiting exoplanets. The transit events provide unique opportunities to characterize the physical properties of exoplanetary systems, they can help us to obtain accurate planetary system parameters, so as to explore the internal structure of the planets; the transmission spectra during the transit events can be used to characterize the atmospheric properties of exoplanets; the Rossiter-McLaughlin effect can provide the hints of dynamical history of the planetary systems; the transit timing variations (TTVs) provide the chances to detect the low mass planets in the same planetary systems. Therefore, transiting exoplanets have been playing a fundamental role in revolutionizing the planetary science.To the first order, a transiting exoplanet will exhibit perfectly periodic transit times and a constant orbital period if it has no companion(s). In some cases the gravitational interaction between planets will trigger relative short-term TTVs. The patterns of these TTVs (e.g., amplitude, frequency, and overall shape) strongly rely on the orbital parameters and masses of the planets involved, so that they can be used to discover additional planet(s). Moreover, when the exoplanets are subject to the long-term effects of tidal forces, the orbital decay induced by tidal dissipation tends to occur in massive planets with shorter orbital periods, and such kind of TTV signals could be used to constrain the planetary tidal quality factor, which can be used to study the dynamical evolution of planetary systems. When an exoplanet is in front of its host star, the light from the host star passes through the planetary atmosphere, and the atmospheric signatures get imprinted on the transmission spectrum. By analyzing the transmission spectrum, the atmospheric chemical composition and physical properties of the transiting exoplanet can be acquired.By utilizing the 2.4m and 1m telescopes of Yunnan Observatories, we have obtained high-quality photometric light curves for transit events of WASP-12, WASP-35 and HAT-P-30/WASP-51 exoplanetary systems. Analyzing the transit light curves using the Markov chain Monte Carlo technique, we have derived the transmission spectrum of WASP-12b, and more accurate physical parameters of the WASP-12, WASP-35 as well as HAT-P-30/WASP-51 systems. Compared the transmission spectrum of WASP-12b with a set of theoretical spectra, we find no evidence for existence of the absorption of TiO and VO in its atmosphere, the obvious Rayleigh scattering and the weak Na signal can also be seen. WASP-12b has a significant change in the planetary orbit, which indicates the orbit is decaying based on the TTV analysis. Furthermore, the current observations can not rule out the possibility of planetary interaction-induced TTV conclusively. We also find that HAT-P-30b/WASP-51b's transits show timing variation, the apsidal precession and an additional perturbing planet could reproduce this signal through our comprehensive dynamical simulations. We have made some predictions for atmospheric properties of WASP-35b and HAT-P-30b/WASP-51b based on newly derived system parameters. |
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