Examinando por Autor "Deleuil, M."

Mostrando 1 - 7 de 7

Acceso Abierto
A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113
(Oxford Academics: Oxford University Press, 2021-01-25) Osborn, Hugh P.; Armstrong, D. J.; Adibekyan, V.; Collins, K. A.; Delgado Mena, E.; Howell, Steve B.; Hellier, C.; King, G. W.; Lillo Box, J.; Nielsen, L. D.; Otegi, J. F.; Santos, N. C.; Ziegler, C.; Anderson, D. R.; Briceño, C.; Burke, C. J.; Bayliss, D.; Barrado, D.; Bryant, E. M.; Brown, D. J. A.; Barros, S. C. C.; Bouchy, F.; Caldwell, D. A.; Conti, D.; Díaz, R. F.; Dragomir, D.; Deleuil, M.; Demanegon, O. D. S.; Dorn, C.; Daylan, T.; Figueira, P.; Helled, R.; Hoyer, S.; Jenkins, J. S.; Jensen, E. L. N.; Latham, D. W.; Law, N.; Louie, D.; Mann, A. W.; Osborn, A.; Pollacco, D.; Rodríguez, D. R.; Rackham, B. V.; Ricker, G.; Scott, N. J.; Sousa, S. G.; Seager, S.; Stassun, K. G.; Smith, J. C.; Strom, P.; Udry, S.; Villaseñor, J. N.; Vanderspek, R.; West, R.; Wheatley, P. J.; Winn, J. N.; Fundacao para a Ciencia e a Tecnologia (FCT); Science and Technology Facilities Council (STFC); Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); UK Space Agency; Dorn, C. [0000-0001-6110-4610]; Anderson, D. [0000-0001-7416-7522]; Barros, S. [0000-0003-2434-3625]; Adibekyan, V. [0000-0002-0601-6199]; Armstrong, D. [0000-0002-5080-4117]; Santos, N. [0000-0003-4422-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We report the discovery of HD 110113 b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD 110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities gathered by the NCORES program, we find that HD 110113 b has a radius of 2.05 ± 0.12 R⊕ and a mass of 4.55 ± 0.62 M⊕. The resulting density of 2.90+0.75−0.59 g cm−3 is significantly lower than would be expected from a pure-rock world; therefore HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. The high incident flux places it within the so-called radius valley; however, HD 110113 b was able to hold on to a substantial (0.1–1 per cent) H–He atmosphere over its ∼4 Gyr lifetime. Through a novel simultaneous Gaussian process fit to multiple activity indicators, we were also able to fit for the strong stellar rotation signal with period 20.8 ± 1.2 d from the RVs and confirm an additional non-transiting planet, HD 110113 c, which has a mass of 10.5 ± 1.2 M⊕ and a period of 6.744+0.008−0.009 d.
Restringido
A remnant planetary core in the hot-Neptune desert
(Springer Nature Research Journals, 2020-07-01) Armstrong, D. J.; López, T. A.; Adibekyan, V.; Booth, R. A.; Bryant, E. M.; Collins, K. A.; Deleuil, M.; Emsenhuber, A.; Huang, C. X.; King, G. W.; Lillo Box, J.; Lissauer, J. J.; Matthews, E.; Mousis, O.; Nielsen, L. D.; Osborn, Hugh P.; Otegi, J.; Santos, N. C.; Sousa, S. G.; Stassun, K. G.; Veras, D.; Ziegler, C.; Acton, J. S.; Almenara, J. M.; Anderson, D. R.; Barrado, D.; Barros, S. C. C.; Bayliss, D.; Belardi, C.; Bouchy, F.; Briceño, C.; Brogi, M.; Brown, D. J. A.; Burleigh, M. R.; Casewell, S. L.; Chausev, A.; Ciardi, D. R.; Collins, K. I.; Colón, K. D.; Cooke, B. F.; Crossfield, J. M.; Díaz, R. F.; Delgado Mena, E.; Gandhi, O. D. S.; Gill, Samuel; Gonzales, E. J.; Goad, M. R.; Günther, M. N.; Helled, R.; Hojjatpanah, S.; Howell, Steve B.; Jackman, J.; Jenkins, J. S.; Jenkins, J. M.; Jensen, E. L. N.; Kennedy, G. M.; Latham, D. W.; Law, N.; Osborn, M.; Pollacco, D.; Queloz, D.; Raynard, L.; Ricker, G. R.; Rowden, P.; Santerne, A.; Schlieder, J. E.; Seager, S.; Sha, L.; Tan, T. G.; Tilbrook, R. H.; Ting, E.; Udry, S.; Vanderspek, R.; Watson, C. A.; West, R. G.; Wilson, P. A.; Winn, J. N.; Wheatley, P.; Villaseñor, J. N.; Vines, J. I.; Zhan, Z.; National Aeronautics and Space Administration (NASA); Fundação para a Ciência e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Science and Technology Facilities Council (STFC); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Collins, K. A. [0000-0002-4317-142X]; Lillo Box, J. [0000-0003-3742-1987]; Matthews, E. [0000-0003-0593-1560]; Sousa, S. [0000-0002-3631-6440]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert'(1,2)(a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b(3), which is thought to have an unusually massive core, and recent discoveries such as LTT9779b(4)and NGTS-4b(5), on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of39.1-2.6+2.7Earth masses and a density of5.2-0.8+0.7grams per cubic centimetre, similar to Earth's. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than3.9-0.9+0.8 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation(6). Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.
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
Masses for the seven planets in K2-32 and K2-233 Four diverse planets in resonant chain and the first young rocky worlds
(EDP Sciences, 2020-08-11) Lillo Box, J.; López, T. A.; Santerne, A.; Nielsen, L. D.; Barros, S. C. C.; Deleuil, M.; Acuña, L.; Mousis, O.; Sousa, S. G.; Adibekyan, V.; Armstrong, D. J.; Barrado, D.; Bayliss, D.; Brown, D. J. A.; Demangeon, O. D. S.; Dumusque, X.; Figueira, P.; Hojjatpanah, S.; Osborn, Hugh P.; Santos, N. C.; Udry, S.; Science and Technology Facilities Council (STFC); Agencia Estatal de Investigación (AEI); Fundacao para a Ciencia e a Tecnologia (FCT); Lillo Box, J. [0000-0003-3742-1987]; López, T. [0000-0001-6622-1250]; Santerne, A. [0000-0002-3586-1316]; Barros, S. [0000-0003-2434-3625]; Deleuil, M. [0000-0001-6036-0225]; Sousa, S. G. [0000-0001-9047-2965]; Adibekyan, V. [0000-0002-0601-6199]; Armstrong, D. J. [0000-0002-5080-4117]; Barrado, D. [0000-0002-5971-9242]; Bayliss, D. [0000-0001-6023-1335]; Brown, D. J. A. [0000-0003-1098-2442]; Demangeon, O. D. S. [0000-0001-7918-0355]; Dumusque, X. [0000-0002-9332-2011]; Figueira, P. [0000-0001-8504-283X]; Hojjatpanah, S. [0000-0002-0417-1902]; Osborn, H. [0000-0002-4047-4724]; Santos, N. C. [0000-0003-4422-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. High-precision planetary densities are key pieces of information necessary to derive robust atmospheric properties for extrasolar planets. Measuring precise masses is the most challenging part of this task, especially in multi-planetary systems. The ESO-K2 collaboration focuses on the follow-up of a selection of multi-planetary systems detected by the K2 mission using the HARPS instrument with this goal in mind. Aims. In this work, we measure the masses and densities of two multi-planetary systems: a four-planet near resonant chain system (K2-32) and a young (~400 Myr old) planetary system consisting of three close-in small planets (K2-233). Methods. We obtained 199 new HARPS observations for K2-32 and 124 for K2-233 covering a long baseline of more than three years. We performed a joint analysis of the radial velocities and K2 photometry with PASTIS to precisely measure and constrained the properties of these planets, focusing on their masses and orbital properties. Results. We find that K2-32 is a compact scaled-down version of the Solar System’s architecture, with a small rocky inner planet (Me = 2.1−1.1+1.3 M⊕, Pe ~ 4.35 days) followed by an inflated Neptune-mass planet (Mb = 15.0−1.7+1.8 M⊕, Pb ~ 8.99 days) and two external sub-Neptunes (Mc = 8.1 ± 2.4 M⊕, Pc ~ 20.66 days; Md = 6.7 ± 2.5 M⊕, Pd ~ 31.72 days). K2-32 becomes one of the few multi-planetary systems with four or more planets known where all have measured masses and radii. Additionally, we constrain the masses of the three planets in the K2-233 system through marginal detection of their induced radial velocity variations. For the two inner Earth-size planets we constrain their masses at a 95% confidence level to be smaller than Mb < 11.3 M⊕ (Pb ~ 2.47 days), Mc < 12.8 M⊕ (Pc ~ 7.06 days). The outer planet is a sub-Neptune size planet with an inferred mass of Md = 8.3−4.7+5.2 M⊕ (Md < 21.1 M⊕, Pd ~ 24.36 days). Conclusions. Our observations of these two planetary systems confirm for the first time the rocky nature of two planets orbiting a young star, with relatively short orbital periods (<7 days). They provide key information for planet formation and evolution models of telluric planets. Additionally, the Neptune-like derived masses of the three planets, K2-32 b, c, d, puts them in a relatively unexplored regime of incident flux and planet mass, which is key for transmission spectroscopy studies in the near future.
Acceso Abierto
Planetary system LHS 1140 revisited with ESPRESSO and TESS
(EDP Sciences, 2020-10-15) Lillo Box, J.; Figueira, P.; Leleu, A.; Acuña, L.; Faria, J. P.; Harada, N.; Santos, N. C.; Correia, A. C. M.; Robutel, P.; Deleuil, M.; Barrado, D.; Sousa, S. G.; Bonfils, X.; Mousis, O.; Almenara, J. M.; Astudillo Defru, N.; Marcq, E.; Udry, S.; Lovis, C.; Pepe, F.; Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); European Commission (EC); Faria, J. [0000-0002-6728-244X]; Correia, A. C. M. [0000-0002-8946-8579]; Leleu, A. [0000-0003-2051-7974]; Lillo Box, J. [0000-0003-3742-1987]; Santos, N. [0000-0003-4422-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. LHS 1140 is an M dwarf known to host two transiting planets at orbital periods of 3.77 and 24.7 days. They were detected with HARPS and Spitzer. The external planet (LHS 1140 b) is a rocky super-Earth that is located in the middle of the habitable zone of this low-mass star. All these properties place this system at the forefront of the habitable exoplanet exploration, and it therefore constitutes a relevant case for further astrobiological studies, including atmospheric observations. Aims. We further characterize this system by improving the physical and orbital properties of the known planets, search for additional planetary-mass components in the system, and explore the possibility of co-orbitals. Methods. We collected 113 new high-precision radial velocity observations with ESPRESSO over a 1.5-yr time span with an average photon-noise precision of 1.07 m s−1. We performed an extensive analysis of the HARPS and ESPRESSO datasets and also analyzed them together with the new TESS photometry. We analyzed the Bayesian evidence of several models with different numbers of planets and orbital configurations. Results. We significantly improve our knowledge of the properties of the known planets LHS 1140 b (Pb ~ 24.7 days) and LHS 1140 c (Pc ~ 3.77 days). We determine new masses with a precision of 6% for LHS 1140 b (6.48 ± 0.46 M⊕) and 9% for LHS 1140 c (mc = 1.78 ± 0.17 M⊕). This reduces the uncertainties relative to previously published values by half. Although both planets have Earth-like bulk compositions, the internal structure analysis suggests that LHS 1140 b might be iron-enriched and LHS 1140 c might be a true Earth twin. In both cases, the water content is compatible to a maximum fraction of 10–12% in mass, which is equivalent to a deep ocean layer of 779 ± 650 km for the habitable-zone planet LHS 1140 b. Our results also provide evidence for a new planet candidate in the system (md = 4.8 ± 1.1M⊕) on a 78.9-day orbital period, which is detected through three independent methods. The analysis also allows us to discard other planets above 0.5 M⊕ for periods shorter than 10 days and above 2 M⊕ for periods up to one year. Finally, our co-orbital analysis discards co-orbital planets in the tadpole and horseshoe configurations of LHS 1140 b down to 1 M⊕ with a 95% confidence level (twice better than with the previous HARPS dataset). Indications for a possible co-orbital signal in LHS 1140 c are detected in both radial velocity (alternatively explained by a high eccentricity) and photometric data (alternatively explained by systematics), however. Conclusions. The new precise measurements of the planet properties of the two transiting planets in LHS 1140 as well as the detection of the planet candidate LHS 1140 d make this system a key target for atmospheric studies of rocky worlds at different stellar irradiations.
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 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.