The TROY project
European Southern Observatory (ESO), Alonso de Cordova 3107,
Vitacura Casilla 19001,
2 Physics Institute, Space Research and Planetary Sciences, Center for Space and Habitability – NCCR PlanetS, University of Bern, Bern, Switzerland
3 Instituto de Astrofísica de Canarias (IAC), 38200 La Laguna, Tenerife, Spain
4 Departmento Astrofísica, Universidad de La Laguna (ULL), 38206 La Laguna, Tenerife, Spain
5 Sub-department of Astrophysics, Department of Physics, University of Oxford, Oxford OX1 3RH, UK
6 Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
7 Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
8 IMCCE, Observatoire de Paris – PSL Research University, UPMC University Paris 06, University Lille 1, CNRS, 77 Avenue Denfert-Rochereau, 75014 Paris, France
9 Department of Physics, University of Coimbra, 3004-516 Coimbra, Portugal
10 CIDMA, Departamento de Física, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
11 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
12 Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
13 ESO, Karl Schwarzschild Strasse 2, 85748 Garching, Germany
14 Departmento de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESAC Campus 28692 Villanueva de la Cañada, Madrid, Spain
Accepted: 27 June 2018
Context. Co-orbital bodies are the byproduct of planet formation and evolution, as we know from the solar system. Although planet-size co-orbitals do not exists in our planetary system, dynamical studies show that they can remain stable for long periods of time in the gravitational well of massive planets. Should they exist, their detection is feasible with the current instrumentation.
Aims. In this paper, we present new ground-based observations searching for these bodies co-orbiting with nine close-in (P < 5 days) planets, using various observing techniques. The combination of all of these techniques allows us to restrict the parameter space of any possible trojan in the system.
Methods. We used multi-technique observations, comprised of radial velocity, precision photometry, and transit timing variations, both newly acquired in the context of the TROY project and publicly available, to constrain the presence of planet-size trojans in the Lagrangian points of nine known exoplanets.
Results. We find no clear evidence of trojans in these nine systems through any of the techniques used down to the precision of the observations. However, this allows us to constrain the presence of any potential trojan in the system, especially in the trojan mass or radius vs. libration amplitude plane. In particular, we can set upper mass limits in the super-Earth mass regime for six of the studied systems.
Key words: planets and satellites: gaseous planets / planets and satellites: fundamental parameters / minor planets, asteroids: general / techniques: radial velocities / techniques: photometric
Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).
Partly based on data obtained with the STELLA robotic telescopes in Tenerife, an AIP facility jointly operated by AIP and IAC.
© ESO 2018