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.

Consideration of both low- and high-resolution transmission spectroscopy is key for obtaining a comprehensive picture of exoplanet atmospheres. In studies of transmission spectra, the continuum information is well established with low-resolution spectra, while the shapes of individual lines are best constrained with high-resolution observations. In this work, we aim to merge high- with low-resolution transmission spectroscopy to place tighter constraints on physical parameters of the atmospheres. We present the analysis of three primary transits of WASP-69 b in the visible (VIS) channel of the CARMENES instrument and perform a combined low- and high-resolution analysis using additional data from HARPS-N, OSIRIS/GTC, and WFC3/HST already available in the literature. We investigate the Na I D1 and D2 doublet, Hα, the Ca II infra-red triplet (IRT), and K I λ7699 Å lines, and we monitor the stellar photometric variability by performing long-term photometric observations with the STELLA telescope. During the first CARMENES observing night, we detected the planet Na I D2 and D1 lines at ∼7 and ∼3σ significance levels, respectively. We measured a D2/D1 intensity ratio of 2.5 ± 0.7, which is in agreement with previous HARPS-N observations. Our modelling of WFC3 and OSIRIS data suggests strong Rayleigh scattering, solar to super-solar water abundance, and a highly muted Na feature in the atmosphere of this planet, in agreement with previous investigations of this target. We use the continuum information retrieved from the low-resolution spectroscopy as a prior to break the degeneracy between the Na abundance, reference pressure, and thermosphere temperature for the high-resolution spectroscopic analysis. We fit the Na I D1 and D2 lines individually and find that the posterior distributions of the model parameters agree with each other within 1σ. Our results suggest that local thermodynamic equilibrium processes can explain the observed D2 /D1 ratio because the presence of haze opacity mutes the absorption features. © 2021 ESO. ; CARMENES is an instrument at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto (Almería, Spain), operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSIC). CARMENES was funded by the Max-Planck-Gesellschaft (MPG), the Consejo Superior de Investigaciones Científicas (CSIC), the Ministerio de Economía y Competitividad (MINECO) and the European Regional Development Fund (ERDF) through projects FICTS-2011-02, ICTS-2017-07-CAHA-4, and CAHA16-CE-3978, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, Landessternwarte Königstuhl, Institut de Ciències de l'Espai, Institut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Cen tro de Astrobiología and Centro Astronómico Hispano-Alemán), with additional contributions by the MINECO, the Deutsche Forschungsgemeinschaft (DFG) through the Major Research Instrumentation Programme and Research Unit FOR2544 "Blue Planets around Red Stars", the Klaus Tschira Stiftung, the states of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía. We acknowledge financial support from the DFG through priority program SPP 1992 "Exploring the Diversity of Extrasolar Planets" (KH 472/3-1) and through grant CA 1795/3, NASA through ROSES-2016/Exoplanets Research Program (NNX17AC03G), the Klaus Tschira Stiftung, the European Research Council under the European Union's Horizon 2020 research and innovation program (694513), the Agencia Estatal de Investigación of the Ministerio de Ciencia, Innovación y Universidades and the ERDF through projects PID2019-109522GB-C5[1:4] and the Centre of Excellence "Severo Ochoa" and "María de Maeztu" awards to the Instituto de Astrofísica de Canarias (SEV-2015-0548), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astrobiología (MDM-2017-0737), and the Generalitat de Catalunya/CERCA programme. ; Peer reviewed

During its four years of photometric observations, the Kepler space telescope detected thousands of exoplanets and exoplanet candidates. One of Kepler's greatest heritages has been the confirmation and characterization of hundreds of multi-planet systems via transit timing variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long timescales that the existing Kepler observations are of insufficient length to confirm and characterize them by means of this technique. To continue with Kepler's unique work, we have organized the "Kepler Object of Interest Network" (KOINet), a multi-site network formed of several telescopes located throughout America, Europe, and Asia. The goals of KOINet are to complete the TTV curves of systems where Kepler did not cover the interaction timescales well, to dynamically prove that some candidates are true planets (or not), to dynamically measure the masses and bulk densities of some planets, to find evidence for non-transiting planets in some of the systems, to extend Kepler's baseline adding new data with the main purpose of improving current models of TTVs, and to build a platform that can observe almost anywhere on the northern hemisphere, at almost any time. KOINet has been operational since March 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01, in addition to the Kepler data acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints on timing precision (at least 1 min) and photometric precision (as good as one part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turnover of its TTVs. We carried out an in-depth study of the system, which is identified in the NASA Data Validation Report as a false positive. Among others, we investigated a gravitationally bound hierarchical triple star system and a planet-star system. While the simultaneous transit fitting of ground- andspace-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system. © ESO 2018. ; Russian Science Foundation, RSF: 14-50-00043 ; LAT-08/2016, 2014-0707 ; Russian Foundation for Basic Research, RFBR: 17-02-00542 ; Lietuvos Mokslo Taryba ; Deutsche Forschungsgemeinschaft, DFG ; Norges ForskningsrÃ¥d: 188910 ; National Science Foundation, NSF: AST-1615315 ; Deutsche Forschungsgemeinschaft, DFG: DR 281/30-1 ; Science and Technology Facilities Council, STFC ; European Regional Development Fund, FEDER: ESP2016-80435-C2-1-R ; European Commission, EC ; NNH05ZDA001C ; Danmarks Grundforskningsfond, DNRF: DNRF106 ; Education, Audiovisual and Culture Executive Agency, EACEA ; Ministério da Educação e Ciência, MEC ; National Aeronautics and Space Administration, NASA: NNX13A124G, NNX13AF62G ; Science and Technology Facilities Council, STFC: ST/P000312/1, ESP2015-65712-C5-4-R ; Ministerio de Economía y Competitividad, MINECO ; Acknowledgements. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant DNRF106). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. E.A. acknowledges support from NASA Grants NNX13A124G, NNX13AF62G; from National Science Foundation (NSF) grant AST-1615315; and from the NASA Astrobiology Institutes Virtual Planetary Laboratory, supported by NASA under cooperative agreement NNH05ZDA001C. S.W. acknowledges support from the Research Council of Norway grant 188910 to finance service observing at the NOT, and support for International Team 265 (Magnetic Activity of M-type Dwarf Stars and the Influence on Habitable Extra-solar Planets) funded by the International Space Science Institute (ISSI) in Bern, Switzerland. J.F. acknowledges funding from the German Research Foundation (DFG) through grant DR 281/30-1. Based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofísica de Canarias. The data presented here were obtained in part with ALFOSC, which is provided by the Instituto de Astrofísica de Andalucía (IAA) under a joint agreement with the University of Copenhagen and NOTSA. Based on observations obtained with the Apache Point Observatory 3.5-m telescope, which is owned and operated by the Astrophysical Research Consortium. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC). This work was supported in part by the Ministry of Education and Science (the basic part of the State assignment, RK no. AAAA-A17-117030310283-7) and by Act no. 211 of the Government of the Russian Federation, agreement no. 02.A03.21.0006. E.H. and I.R. acknowledge support by the Spanish Ministry of Economy and Competitiveness (MINECO) and the Fondo Europeo de Desarrollo Regional (FEDER) through grant ESP2016-80435-C2-1-R, as well as the support of the Generalitat de Catalunya/CERCA programme. E.P., G.T., and Š.M. acknowledge support from the Research Council of Lithuania (LMT) through grant LAT-08/2016. C.D.C. is supported by the Erasmus Mundus Joint Doctorate Program by grant number 2014-0707 from the EACEA of the European Commission. S.E. acknowledges support by the Russian Science Foundation grant No. 14-50-00043 for conducting photometric observations of exoplanets of Kepler's mission. S.I. acknowledges Russian Foundation for Basic Research (project No. 17-02-00542) for support in the processing of the observations. K.P. acknowledges support from the UK Science and Technology Facilities Council through STFC grant ST/P000312/1. H.J.D. acknowledges support by grant ESP2015-65712-C5-4-R of the Spanish Secretary of State for R&D&i (MINECO). KOINet thanks the telescope operators for their invaluable help during some of the observing campaigns at the IAC80 telescope. The IAC80 telescope is operated on the island of Tenerife by the Instituto de Astrofísica de Canarias in the Spanish Observatorio del Teide. C.v.E. is grateful for the invaluable help and contribution of all the telescope operators involved in this work. Eric Agol acknowledges support from a Guggenheim Fellowship.

Context. The existence of hot Jupiters is still not well understood. Two main channels are thought to be responsible for their current location: a smooth planet migration through the protoplanetary disk or the circularization of an initial highly eccentric orbit by tidal dissipation leading to a strong decrease in the semimajor axis. Different formation scenarios result in different observable effects, such as orbital parameters (obliquity and eccentricity) or frequency of planets at different stellar ages. Aims. In the context of the GAPS Young Objects project, we are carrying out a radial velocity survey with the aim of searching and characterizing young hot-Jupiter planets. Our purpose is to put constraints on evolutionary models and establish statistical properties, such as the frequency of these planets from a homogeneous sample. Methods. Since young stars are in general magnetically very active, we performed multi-band (visible and near-infrared) spectroscopy with simultaneous GIANO-B + HARPS-N (GIARPS) observing mode at TNG. This helps in dealing with stellar activity and distinguishing the nature of radial velocity variations: stellar activity will introduce a wavelength-dependent radial velocity amplitude, whereas a Keplerian signal is achromatic. As a pilot study, we present here the cases of two known hot Jupiters orbiting young stars: HD 285507 b and AD Leo b. Results. Our analysis of simultaneous high-precision GIARPS spectroscopic data confirms the Keplerian nature of the variation in the HD 285507 radial velocities and refines the orbital parameters of the hot Jupiter, obtaining an eccentricity consistent with a circular orbit. Instead, our analysis does not confirm the signal previously attributed to a planet orbiting AD Leo. This demonstrates the power of the multi-band spectroscopic technique when observing active stars. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)