Examinando por Autor "Fossati, L."

Mostrando 1 - 6 de 6

Acceso Abierto
CHEOPS observations of the HD 108236 planetary system: a fifth planet, improved ephemerides, and planetary radii
(EDP Sciences, 2021-02-19) Bonfanti, A.; Delrez, L.; Hooton, M. J.; Wilson, T. G.; Fossati, L.; Alibert, Y.; Hoyer, S.; Mustill, A. J.; Osborn, H. P.; Adibekyan, V.; Gandolfi, D.; Van Eylen, V.; Viotto, V.; Walter, I.; Walton, N. A.; Wildi, F.; Wolter, D.; Salmon, S.; Sousa, S. G.; Tuson, A.; Van Grootel, V.; Cabrera, J.; Nascimbeni, V.; Maxted, P. F. L.; Barros, S. C. C.; Billot, N.; Bonfils, X.; Borsato, L.; Broeg, C.; Davies, M. B.; Deleuil, M.; Demangeon, O. D. S.; Fridlund, M.; Lacedelli, G.; Lendl, M.; Persson, C.; Santos, N. C.; Scandariato, G.; Szabó, Gy. M.; Collier Cameron, A.; Udry, S.; Benz, W.; Beck, M.; Ehrenreich, D.; Fortier, A.; Isaak, K. G.; Queloz, D.; Alonso, R.; Asquier, J.; Bandy, T.; Bárczy, T.; Barrado, D.; Barragán, O.; Baumjohann, W.; Beck, T.; Bekkelien, A.; Bergomi, M.; Brandeker, A.; Busch, M. D.; Cessa, V.; Charnoz, S.; Chazelas, B.; Van Damme, C. C.; Demory, B. O.; Erikson, A.; Farinato, J.; Futyan, D.; García Muñoz, Antonio; Gillon, M.; Guedel, M.; Guterman, P.; Hasiba, J.; Heng, K.; Hernández, E.; Kiss, L.; Kuntzer, T.; Laskar, J.; Lecavelier des Etangs, A.; Lovis, C.; Magrin, D.; Malvasio, L.; Marafatto, L.; Michaelis, H.; Munari, M.; Olofsson, G.; Ottacher, H.; Ottensamer, R.; Pagano, I.; Pallé, E.; Peter, G.; Piazza, D.; Piotto, G.; Pollacco, D.; Ragazzoni, R.; Rando, N.; Ratti, F.; Rauer, H.; Ribas, I.; Rieder, M.; Rohlfs, R.; Safa, F.; Salatti, M.; Ségransan, D.; Simon, A. E.; Smith, A. M. S.; Sordet, Michael; Steller, M.; Thomas, N.; Tschentscher, M.; Swiss Space Office (SSO); La Silla Observatory; Austrian Research Promotion Agency (FFG); European Research Council (ERC); Swiss National Science Foundation (SNSF); Agencia Estatal de Investigación (AEI); Generalitat de Catalunya; European Space Agency (ESA); Fundacao para a Ciencia e a Tecnologia (FCT); Belgian Federal Science Policy Office (BELSPO); Hungarian National Research, Development and Innovation Office (NKFIH); Istituto Nazionale di Astrofisica (INAF); Swedish National Infrastructure for Computing (SNIC); Bonfanti, A. [0000-0002-1916-5935]; Cameron, A. [0000-0002-8863-7828]; Santos, N. [0000-0003-4422-2919]; Mustill, A. J. [0000-0002-2086-3642]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The detection of a super-Earth and three mini-Neptunes transiting the bright (V = 9.2 mag) star HD 108236 (also known as TOI-1233) was recently reported on the basis of TESS and ground-based light curves. Aims. We perform a first characterisation of the HD 108236 planetary system through high-precision CHEOPS photometry and improve the transit ephemerides and system parameters. Methods. We characterise the host star through spectroscopic analysis and derive the radius with the infrared flux method. We constrain the stellar mass and age by combining the results obtained from two sets of stellar evolutionary tracks. We analyse the available TESS light curves and one CHEOPS transit light curve for each known planet in the system. Results. We find that HD 108236 is a Sun-like star with R⋆ = 0.877 ± 0.008 R⊙, M⋆ = 0.869−0.048+0.050 M⊙, and an age of 6.7−5.1+4.0 Gyr. We report the serendipitous detection of an additional planet, HD 108236 f, in one of the CHEOPS light curves. For this planet, the combined analysis of the TESS and CHEOPS light curves leads to a tentative orbital period of about 29.5 days. From the light curve analysis, we obtain radii of 1.615 ± 0.051, 2.071 ± 0.052, 2.539−0.065+0.062, 3.083 ± 0.052, and 2.017−0.057+0.052 R⊕ for planets HD 108236 b to HD 108236 f, respectively. These values are in agreement with previous TESS-based estimates, but with an improved precision of about a factor of two. We perform a stability analysis of the system, concluding that the planetary orbits most likely have eccentricities smaller than 0.1. We also employ a planetary atmospheric evolution framework to constrain the masses of the five planets, concluding that HD 108236 b and HD 108236 c should have an Earth-like density, while the outer planets should host a low mean molecular weight envelope. Conclusions. The detection of the fifth planet makes HD 108236 the third system brighter than V = 10 mag to host more than four transiting planets. The longer time span enables us to significantly improve the orbital ephemerides such that the uncertainty on the transit times will be of the order of minutes for the years to come. A comparison of the results obtained from the TESS and CHEOPS light curves indicates that for a V ~ 9 mag solar-like star and a transit signal of ~500 ppm, one CHEOPS transit light curve ensures the same level of photometric precision as eight TESS transits combined, although this conclusion depends on the length and position of the gaps in the light curve.
Acceso Abierto
Erratum: The first planet detected in the WTS: an inflated hot-Jupiter in a 3.35 day orbit around a late F-star
(Oxford Academics: Blackwell Publishing, 2020-07-28) Cappetta, M.; Saglia, R. P.; Birkby, J. L.; Koppenhoefer, J.; Pinfield, D. J.; Hodgkin, S. T.; Cruz, P.; Kovács, G.; Sipocz, B.; Barrado, D.; Nefs, B.; Pavlenko, Y. V.; Fossati, L.; del Burgo, C.; Martín, E. L.; Snellen, J.; Barnes, J.; Campbell, D.; Catalan, S.; Gálvez Ortiz, M. C.; Goulding, N.; Haswell, C. A.; Ivanyuk, O.; Jones, H.; Kuznetsov, M.; Lodieu, N.; Marocco, F.; Mislis, D.; Murgas Alcaino, F.; Napiwotzki, R.; Pallé, E.; Pollacco, D.; Sarro Baro, L.; Steele, P.; Stoev, H.; Tata, R.; Zendejas, J.; Solano, Enrique; 0000-0003-0987-1593
Debido a su tipología(Corrección), carece de Abstract. Due to its typology, it has no Abstract. This is a correction to: Monthly Notices of the Royal Astronomical Society, Volume 427, Issue 3, December 2012, Pages 1877–1890, https://doi.org/10.1111/j.1365-2966.2012.21937.x
Acceso Abierto
Six transiting planets and a chain of Laplace resonances in TOI-178
(EDP Sciences, 2021-05-06) Leleu, A.; Alibert, Y.; Hara, N. C.; Hooton, M. J.; Wilson, T. G.; Robutel, P.; Delisle, J. B.; Laskar, J.; Hoyer, S.; Lovis, C.; Bryant, E. M.; Ducrot, E.; Gillen, E.; Alonso, R.; Pepe, F. A.; Correia, A. C. M.; Alves, D.; Cooke, B. F.; Cristiani, S.; Damasso, M.; Simon, A. E.; Angerhausen, D.; Günther, M. N.; Beck, M.; Queloz, D.; Dumusque, X.; Beck, T.; Di Marcoantonio, P.; Ehrenreich, D.; Erikson, A.; Olofsson, G.; Bourrier, V.; Reimers, C.; Futyan, D.; Boué, G.; Fridlund, M.; Gandolfi, D.; García Muñoz, Antonio; Peter, G.; Burleigh, M. R.; Bárczy, T.; Guillon, M.; Goad, M. R.; Cabrera, J.; Chamberlain, S.; Moyaro, M.; Davies, M. B.; Thomas, N.; Isaak, K.; Deleuil, M.; Heng, K.; Jehin, E.; Jenkins, J. S.; Anglada Escudé, G.; Pedersen, P. P.; Figueira, P.; Verrecchia, F.; Lecavelier des Etangs, A.; Fortier, A.; Lam, K.; Lendl, M.; Lillo Box, J.; Sousa, S. G.; García, L. J.; Osborn, Hugh P.; Gill, S.; Maxted, P. F. L.; McCormac, J.; Mehner, A.; Tilbrook, R. H.; Guedel, M.; Nunes, N. J.; Oshagh, M.; Ottensamer, R.; Charnoz, S.; Haldemann, J.; Sebastian, D.; Jordán, A.; Bekkelien, A.; Piotto, G.; Kiss, L.; Persson, C. M.; Polenta, G.; Pollacco, D.; Acton, J. S.; Lo Curto, G.; Brandeker, A.; Rando, N.; Magrin, D.; Ragazzoni, R.; Ratti, F.; Rauer, H.; Barrado, D.; Micela, G.; Molaro, P.; Ribas, I.; Santos, N. C.; Scandariato, G.; Billot, N.; Murray, C. A.; Zapatero Osorio, M. R.; Pagano, I.; Demory, B. O.; Sozzetti, A.; Pallé, E.; Smith, A. M. S.; Steller, M.; Suárez Mascareño, A.; Henderson, B.; Anderson, D. R.; Poretti, E.; Fossati, L.; Triaud, A.; Pozuelos, F. J.; Thompson, S.; Turner, O.; Udry, S.; Corral Van Damme, C.; Raynard, L.; Adibekyan, V.; Rebolo, R.; Vines, J. I.; Walton, N. A.; West, R. G.; Di Persio, G.; Schneider, J.; Delrez, L.; Allart, R.; Allende Prieto, C.; Nascimbeni, V.; Sestovic, M.; Cameron, A. C.; Szabó, G. M.; Kristiansen, M. H.; Barros, S. C. C.; Ségransan, D.; Asquier, J.; Baumjohann, W.; Bayliss, D.; Demangeon, O. D. S.; Van Grootel, V.; Martins, C. J. A. P.; Bonfanti, A.; Venus, H.; Benz, W.; Bonfils, X.; Bouchy, F.; Hogan, A. E.; Wheatley, P. J.; Wolter, D.; Broeg, C.; Buder, M.; Burdanov, A.; Lavie, B.; González Hernández, Carmen; Alvarez, M. [0000-0002-6786-2620]; Carrasco Martínez, J. M. [0000-0002-3029-5853]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. In this context, TOI-178 has been the subject of particular attention since the first TESS observations hinted at the possible presence of a near 2:3:3 resonant chain. Here we report the results of observations from CHEOPS, ESPRESSO, NGTS, and SPECULOOS with the aim of deciphering the peculiar orbital architecture of the system. We show that TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, with radii ranging from 1.152−0.070+0.073 to 2.87−0.13+0.14 Earth radii and periods of 1.91, 3.24, 6.56, 9.96, 15.23, and 20.71 days. All planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet, jumping from 1.02−0.23+0.28 to 0.177−0.061+0.055 times the Earth’s density between planets c and d. Using Bayesian interior structure retrieval models, we show that the amount of gas in the planets does not vary in a monotonous way, contrary to what one would expect from simple formation and evolution models and unlike other known systems in a chain of Laplace resonances. The brightness of TOI-178 (H = 8.76 mag, J = 9.37 mag, V = 11.95 mag) allows for a precise characterisation of its orbital architecture as well as of the physical nature of the six presently known transiting planets it harbours. The peculiar orbital configuration and the diversity in average density among the planets in the system will enable the study of interior planetary structures and atmospheric evolution, providing important clues on the formation of super-Earths and mini-Neptunes.
Acceso Abierto
The GAPS programme at TNG XXII. The GIARPS view of the extended helium atmosphere of HD 189733 b accounting for stellar activity
(EDP Sciences, 2020-07-07) Guilluy, G.; Andretta, V.; Borsa, F.; Giacobbe, P.; Sozzetti, A.; Covino, E.; Bourrier, V.; Fossati, L.; Bonomo, A. S.; Esposito, M.; Giampapa, M. S.; Harutyunyan, A.; Rainer, M.; Brogi, M.; Bruno, G.; Claudi, R.; Frustagli, G.; Lanza, A. F.; Mancini, L.; Pino, L.; Poretti, E.; Scandariato, G.; Affer, L.; Baffa, C.; Baruffolo, A.; Benatti, S.; Biazzo, K.; Bignamini, A.; Boschin, W.; Carleo, I.; Cecconi, M.; Cosentino, R.; Damasso, M.; Desidera, S.; Falcini, G.; Martínez Fiorenzano, A. F.; Ghedina, A.; González Álvarez, E.; Guerra, J.; Hernández, N.; Leto, G.; Maggio, A.; Malavolta, L.; Maldonado, J.; Micela, G.; Molinari, E.; Nascimbeni, V.; Pagano, I.; Pedani, M.; Piotto, G.; Reiners, A.; Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF); Swiss National Science Foundation (SNSF); European Research Council (ERC); Deutsche Forschungsgemeinschaft (DFG); Claudi, R. [orcid.org/0000-0001-7707-5105]; Leto, G. [orcid.org/0000-0002-0040-5011]; Ghedina, A. [orcid.org/0000-0003-4702-5152]; Pino, L. [orcid.org/0000-0002-1321-8856]; Damaso, M. [orcid.org/0000-0001-9984-4278]; Cosentino, R. [orcid.org/0000-0003-1784-1431]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Exoplanets orbiting very close to their parent star are strongly irradiated. This can lead the upper atmospheric layers to expand and evaporate into space. The metastable helium (He I) triplet at 1083.3 nm has recently been shown to be a powerful diagnostic to probe extended and escaping exoplanetary atmospheres. Aims. We perform high-resolution transmission spectroscopy of the transiting hot Jupiter HD 189733 b with the GIARPS (GIANO-B + HARPS-N) observing mode of the Telescopio Nazionale Galileo, taking advantage of the simultaneous optical+near infrared spectral coverage to detect He I in the planet’s extended atmosphere and to gauge the impact of stellar magnetic activity on the planetary absorption signal. Methods. Observations were performed during five transit events of HD 189733 b. By comparison of the in-transit and out-of-transit GIANO-B observations, we computed high-resolution transmission spectra. We then used them to perform equivalent width measurements and carry out light-curves analyses in order to consistently gauge the excess in-transit absorption in correspondence with the He I triplet. Results. We spectrally resolve the He I triplet and detect an absorption signal during all five transits. The mean in-transit absorption depth amounts to 0.75 ± 0.03% (25σ) in the core of the strongest helium triplet component. We detect night-to-night variations in the He I absorption signal likely due to the transit events occurring in the presence of stellar surface inhomogeneities. We evaluate the impact of stellar-activity pseudo-signals on the true planetary absorption using a comparative analysis of the He I 1083.3 nm (in the near-infrared) and the Hα (in the visible) lines. Using a 3D atmospheric code, we interpret the time series of the He I absorption lines in the three nights not affected by stellar contamination, which exhibit a mean in-transit absorption depth of 0.77 ± 0.04% (19σ) in full agreement with the one derived from the full dataset. In agreement with previous results, our simulations suggest that the helium layers only fill part of the Roche lobe. Observations can be explained with a thermosphere heated to ~12 000 K, expanding up to ~1.2 planetary radii, and losing ~1 g s−1 of metastable helium. Conclusions. Our results reinforce the importance of simultaneous optical plus near infrared monitoring when performing high-resolution transmission spectroscopy of the extended and escaping atmospheres of hot planets in the presence of stellar activity.
Acceso Abierto
The hot dayside and asymmetric transit of WASP-189 b seen by CHEOPS
(EDP Sciences, 2020-11-09) Lendl, M.; Csizmadia, Sz.; Deline, A.; Fossati, L.; Kitzmann, D.; Heng, K.; Hoyer, S.; Salmon, S.; Benz, W.; Broeg, C.; Ehrenreich, D.; Malvasio, L.; Marafatto, L.; Michaelis, H.; Munari, M.; Nascimbeni, V.; Olofsson, G.; Ottacher, H.; Ottensamer, R.; Pagano, I.; Pallé, E.; Peter, G.; Pizza, D.; Piotto, G.; Pollacco, D.; Ratti, F.; Rauer, H.; Ragazzoni, R.; Rando, N.; Ribas, I.; Rieder, M.; Rohlfs, R.; Safa, F.; Santos, N. C.; Scandariato, G.; Ségransan, D.; Simón, A. E.; Singh, V.; Smith, A. M. S.; Sordet, Michael; Sousa, S. G.; Steller, M.; Szabó, Gy. M.; Thomas, N.; Tschentscher, M.; Udry, S.; Viotto, V.; Walter, I.; Walton, N. A.; Wildi, F.; Wolter, D.; Fortier, A.; Queloz, D.; Bonfanti, A.; Brandeker, A.; Collier Cameron, A.; Delrez, L.; García Muñoz, Antonio; Hooton, M. J.; Maxted, P. F. L.; Morris, B. M.; Van Grootel, V.; Wilson, T. G.; Alibert, Y.; Alonso, R.; Asquier, J.; Bandy, T.; Bárczy, T.; Barrado, D.; Barros, S. C. C.; Baumjohann, W.; Beck, M.; Beck, T.; Bekkelien, A.; Bergomi, M.; Billot, N.; Biondi, F.; Bonfils, X.; Bourrier, V.; Busch, M. D.; Cabrera, J.; Cessa, V.; Charnoz, S.; Chazelas, B.; Corral Van Damme, C.; Davies, M. B.; Deleuil, M.; Demangeon, O. D. S.; Demory, B. O.; Erikson, A.; Farinato, J.; Fridlund, M.; Futyan, D.; Gandolfi, D.; Gillon, M.; Guterman, P.; Hasiba, J.; Hernández, E.; Isaak, K. G.; Kiss, L.; Kuntzer, T.; Lecavelier des Etangs, A.; Lüftinger, T.; Laskar, J.; Lovis, C.; Magrin, D.; Austrian Research Promotion Agency (FFG); Deutsche Forschungsgemeinschaft (DFG); European Research Council (ERC); Swiss National Science Foundation (SNSF); Agencia Estatal de Investigación (AEI); Fundação para a Ciência e a Tecnologia (FCT); National Research Development and Innovation Office, Hungarian (NKFIH); Agenzia Spaziale Italiana (ASI); Generalitat de Catalunya; European Space Agency (ESA); Fundacao para a Ciencia e a Tecnologia (FCT); Belgian Federal Science Policy Office (BELSPO); Istituto Nazionale di Astrofisica (INAF); Wilson, T. G. [0000-0001-8749-1962]; Cameron, A. [0000-0002-8863-7828]; Fridlund, M. [0000-0002-0855-8426]; Cabrera, J. [0000-0001-6653-5487]; Barros, S. [0000-0003-2434-3625]; Santos, N. [0000-0003-4422-2919]; Piotto, G. [0000-0002-9937-6387]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The CHEOPS space mission dedicated to exoplanet follow-up was launched in December 2019, equipped with the capacity to perform photometric measurements at the 20 ppm level. As CHEOPS carries out its observations in a broad optical passband, it can provide insights into the reflected light from exoplanets and constrain the short-wavelength thermal emission for the hottest of planets by observing occultations and phase curves. Here, we report the first CHEOPS observation of an occultation, namely, that of the hot Jupiter WASP-189 b, a MP ≈ 2MJ planet orbiting an A-type star. We detected the occultation of WASP-189 b at high significance in individual measurements and derived an occultation depth of dF = 87.9 ± 4.3 ppm based on four occultations. We compared these measurements to model predictions and we find that they are consistent with an unreflective atmosphere heated to a temperature of 3435 ± 27 K, when assuming inefficient heat redistribution. Furthermore, we present two transits of WASP-189 b observed by CHEOPS. These transits have an asymmetric shape that we attribute to gravity darkening of the host star caused by its high rotation rate. We used these measurements to refine the planetary parameters, finding a ~25% deeper transit compared to the discovery paper and updating the radius of WASP-189 b to 1.619 ± 0.021RJ. We further measured the projected orbital obliquity to be λ = 86.4−4.4+2.9°, a value that is in good agreement with a previous measurement from spectroscopic observations, and derived a true obliquity of Ψ = 85.4 ± 4.3°. Finally, we provide reference values for the photometric precision attained by the CHEOPS satellite: for the V = 6.6 mag star, and using a 1-h binning, we obtain a residual RMS between 10 and 17 ppm on the individual light curves, and 5.7 ppm when combining the four visits.
Acceso Abierto
The VLT-FLAMES Tarantula Survey
(Astronomical Science, 2020-09-01) Evans, C. J.; Lennon, D.; Langer, N.; Almeida, L.; Bartlett, E.; Bastian, N.; Bestenlehner, J. M.; Britavskiy, N.; Castro, N.; Clark, S.; Crowther, P. A.; De Koter, A.; De Mink, S.; Dufton, P. L.; Fossati, L.; García, M.; Gieles, M.; Gräfener, G.; Grin, N.; Hénault Brunet, V.; Herrero, A.; Howarth, I.; Izzard, R.; Kalari, V.; Maíz Apellániz, J.; Markova, N.; Najarro, F.; Patrick, Lee R.; Puls, J.; Ramírez Agudelo, O.; Renzo, M.; Sabín Sanjulián, C.; Sana, H.; Schneider, F.; Schootemeijer, A.; Simón Díaz, S.; Smartt, S.; Taylor, W.; Tramper, F.; Van Loon, J.; Villaseñor, J.; Vink, J. S.; Walborn, N.
The VLT-FLAMES Tarantula Survey (VFTS) was an ESO Large Programme that has provided a rich, legacy dataset for studies of both resolved and integrated populations of massive stars. Initiated in 2008 (ESO Period 82), we used the Fibre Large Array Multi Element Spectrograph (FLAMES) to observe more than 800 massive stars in the dramatic 30 Doradus star-forming region in the Large Magellanic Cloud. At the start of the survey the importance of multiplicity among high-mass stars was becoming evident, so a key feature was multi-epoch spectroscopy to detect radial-velocity shifts arising from binary motion. Here we summarise some of the highlights from the survey and look ahead to the future of the field.