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2 results on '"C, Barros S"'

1. Exploiting timing capabilities of the CHEOPS mission with warm-Jupiter planets

Author

L, Borsato, G, Piotto, D, Gandolfi, V, Nascimbeni, G, Lacedelli, F, Marzari, N, Billot, P, Maxted, G, Sousa S, C, Cameron A, A, Bonfanti, T, Wilson, L, Serrano, Z, Garai, Y, Alibert, R, Alonso, J, Asquier, T, Bárczy, T, Bandy, D, Barrado, C, Barros S, W, Baumjohann, M, Beck, T, Beck, W, Benz, X, Bonfils, A, Brandeker, C, Broeg, J, Cabrera, S, Charnoz, S, Csizmadia, M, Davies, M, Deleuil, L, Delrez, D, Demangeon O, B, Demory, A, Lecavelier des Etangs, D, Ehrenreich, A, Erikson, G, Escudé, A, Fortier, L, Fossati, M, Fridlund, M, Gillon, M, Guedel, J, Hasiba, K, Heng, S, Hoyer, G, Isaak K, L, Kiss L, E, Kopp, J, Laskar, M, Lendl, C, Lovis, D, Magrin, M, Munari, R, Ottensamer, G, Peter, R, Ragazzoni, N, Rando, E, Simon A, M, Steller, G, Olofsson, I, Pagano, E, Palle, D, Pollacco, D, Queloz, H, Rauer, I, Ribas, D, Segransan, M, Santos N, G, Scandariato, A, Smith, M, Szabo G, N, Thomas, S, Udry, Grootel V, Van, and A, Walton N

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

We present 17 transit light curves of seven known warm-Jupiters observed with the CHaracterising ExOPlanet Satellite (CHEOPS). The light curves have been collected as part of the CHEOPS Guaranteed Time Observation (GTO) program that searches for transit-timing variation (TTV) of warm-Jupiters induced by a possible external perturber to shed light on the evolution path of such planetary systems. We describe the CHEOPS observation process, from the planning to the data analysis. In this work we focused on the timing performance of CHEOPS, the impact of the sampling of the transit phases, and the improvement we can obtain combining multiple transits together. We reached the highest precision on the transit time of about 13-16 s for the brightest target (WASP-38, G = 9.2) in our sample. From the combined analysis of multiple transits of fainter targets with G >= 11 we obtained a timing precision of about 2 min. Additional observations with CHEOPS, covering a longer temporal baseline, will further improve the precision on the transit times and will allow us to detect possible TTV signals induced by an external perturber., Comment: 23 pages, 19 figures, 8 tables. Accepted for publication in MNRAS

Published
2021

2. SOPHIE velocimetry of Kepler transit candidates XVIII. Radial velocity confirmation, absolute masses and radii, and origin of the Kepler-419 multiplanetary system.

Author

Almenara, J. M., R. F. Díaz, Hébrard, G., Mardling, R., Damiani, C., Santerne, A., Bouchy, F., C. Barros, S. C., Boisse, I., Bonfils, X., Bonomo, A. S., Courcol, B., Demangeon, O., Deleuil, M., Rey, J., Udry, S., and Wilson, P. A.

Subjects
PLANETARY systems, VELOCIMETRY, SPECTROGRAPHS, ASTRONOMICAL photometry, PLANETARY orbits
Abstract

Kepler-419 is a planetary system discovered by the Kepler photometry which is known to harbour two massive giant planets: an inner 3 MJ transiting planet with a 69.8-day period, highly eccentric orbit, and an outer 7.5 MJ non-transiting planet predicted from the transit-timing variations (TTVs) of the inner planet b to have a 675-day period, moderately eccentric orbit. Here we present new radial velocity (RV) measurements secured over more than two years with the SOPHIE spectrograph, where both planets are clearly detected. The RV data is modelled together with the Kepler photometry using a photodynamical model. The inclusion of velocity information breaks the MR−3 degeneracy inherent in timing data alone, allowing us to measure the absolute stellar and planetary radii and masses. With uncertainties of 12 and 13% for the stellar and inner planet radii, and 35, 24, and 35% for the masses of the star, planet b, and planet c, respectively, these measurements are the most precise to date for a single host star system using this technique. The transiting planet mass is determined at better precision than the star mass. This shows that modelling the radial velocities and the light curve together in systems of dynamically interacting planets provides a way of characterising both the star and the planets without being limited by knowledge of the star. On the other hand, the period ratio and eccentricities place the Kepler-419 system in a sweet spot; had around twice as many transits been observed, the mass of the transiting planet could have been measured using its own TTVs. Finally, the origin of the Kepler-419 system is discussed. We show that the system is near a coplanar high-eccentricity secular fixed point, related to the alignment of the orbits, which has prevented the inner orbit from circularising. For most other relative apsidal orientations, planet b’s orbit would be circular with a semi-major axis of 0.03 au. This suggests a mechanism for forming hot Jupiters in multiplanetary systems without the need of high mutual inclinations. [ABSTRACT FROM AUTHOR]

Published
2018
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