Suchergebnisse

Theoretical calculations and some indirect observations show that massive exoplanets on tight orbits must decay due to tidal dissipation within their host stars. This orbital evolution could be observationally accessible through precise transit timing over a course of decades. The rate of planetary in-spiraling may not only help us to understand some aspects of evolution of planetary systems, but also can be used as a probe of the stellar internal structure. In this paper we present results of transit timing campaigns organized for a carefully selected sample of the Northern hemisphere hot Jupiter-like planets which were found to be the best candidates for detecting planet-star tidal interactions. Among them, there is the WASP-12 system which is the best candidate for possessing an in-falling giant exoplanet. Our new observations support the scenario of orbital decay of WASP-12 b and allow us to refine its rate. The derived tidal quality parameter of the host star Q¿ ¿ = (1.82 ± 0.32) × 105 is in agreement with theoretical predictions for subgiant stars. For the remaining systems - HAT-P-23, KELT-1, KELT-16, WASP-33, and WASP-103 - our transit timing data reveal no deviations from the constant-period models, hence constraints on the individual rates of orbital decay were placed. The tidal quality parameters of host stars in at least four systems - HAT-P-23, KELT-1, WASP-33, and WASP-103 - were found to be greater than the value reported for WASP-12. This is in line with the finding that those hosts are main sequence stars, for which efficiency of tidal dissipation is predicted to be relatively weak. © 2018 Copernicus Foundation for Polish Astronomy. All rights reserved.© 2018 Copernicus Foundation for Polish Astronomy. All rights reserved. ; We thank the referee for valuable comments which improved the paper. We also thank Dr. Laetitia Delrez and Dr. Pedro Sada for sharing the WASP-103 and HAT-P-23 light curves with us. GM and MS acknowledge the financial support from the National Science Centre, Poland through grant no. 2016/23/B/ST9/00579. MF acknowledges financial support from grants AYA2014-54348-C3-1-R and AYA2016-79425-C3-3-P of the Spanish Ministry of Economy and Competitiveness (MINECO), co-funded with EU FEDER funds. DD acknowledges the financial support of projects DN 08-1/2016, and DN 08-20/2016 of National Science Foundation of Bulgarian Ministry of education and science as well as by project RD 08-142 of Shumen University. CvE acknowledges funding for the Stellar Astrophysics Centre, which is provided by The Danish National Research Foundation (Grant agreement no.: DNRF106). DM acknowledges support from the National Science Centre (NCN) grant no. 2016/21/B/ST9/01126. A part of this paper is the result of the exchange and joint research project >Spectral and photometric studies of variable stars> between the Polish and Bulgarian Academies of Sciences. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 730890. This material reflects only the authors views and the Commission is not liable for any use that may be made of the information contained therein. This research is based on (1) data obtained at the 1.5m telescope of the Sierra Nevada Observatory (Spain), which is operated by the Consejo Superior de Investigaciones Cientificas (CSIC) through the Instituto de Astrofisica de Andalucia, (2) data collected with telescopes at the Rozhen National Astronomical Observatory, (3) observations made with the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council, (4) observationsmade with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma, and (5) observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.