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Start Over Author "Bonfils, X." Publisher stockholms universitet, institutionen for astronomi
13 results on '"Bonfils, X."'

1. A stellar occultation by the transneptunian object (50000) Quaoar observed by CHEOPS

Author

Morgado, B. E., Bruno, G., Gomes-Júnior, A. R., Pagano, I, Sicardy, B., Fortier, A., Desmars, J., Maxted, P. F. L., Braga-Ribas, F., Queloz, D., Sousa, S. G., Ortiz, J. L., Brandeker, Alexis, Cameron, A. Collier, Pereira, C. L., Florén, Hans Gustav, Hara, N., Souami, D., Isaak, K. G., Olofsson, Göran, Santos-Sanz, P., Wilson, T. G., Broughton, J., Alibert, Y., Alonso, R., Anglada, G., Bárczy, T., Barrado, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Bonfils, X., Broeg, C., Cabrera, J., Charnoz, S., Csizmadia, S., Davies, M. B., Deleuil, M., Delrez, L., Demangeon, O. D. S., Demory, B. O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Gandolfi, D., Gillon, M., Güdel, M., Heng, K., Hoyer, S., Kiss, L. L., Laskar, J., des Etangs, A. Lecavelier, Lendl, M., Lovis, C., Magrin, D., Marafatto, L., Nascimbeni, V, Ottensamer, R., Pallé, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Ragazzoni, R., Rando, N., Ratti, F., Rauer, H., Reimers, C., Ribas, I, Santos, N. C., Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Steller, M., Szabó, G. M., Thomas, N., Udry, S., Van Grootel, V., Walton, N. A., Westerdorff, K., Morgado, B. E., Bruno, G., Gomes-Júnior, A. R., Pagano, I, Sicardy, B., Fortier, A., Desmars, J., Maxted, P. F. L., Braga-Ribas, F., Queloz, D., Sousa, S. G., Ortiz, J. L., Brandeker, Alexis, Cameron, A. Collier, Pereira, C. L., Florén, Hans Gustav, Hara, N., Souami, D., Isaak, K. G., Olofsson, Göran, Santos-Sanz, P., Wilson, T. G., Broughton, J., Alibert, Y., Alonso, R., Anglada, G., Bárczy, T., Barrado, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Bonfils, X., Broeg, C., Cabrera, J., Charnoz, S., Csizmadia, S., Davies, M. B., Deleuil, M., Delrez, L., Demangeon, O. D. S., Demory, B. O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Gandolfi, D., Gillon, M., Güdel, M., Heng, K., Hoyer, S., Kiss, L. L., Laskar, J., des Etangs, A. Lecavelier, Lendl, M., Lovis, C., Magrin, D., Marafatto, L., Nascimbeni, V, Ottensamer, R., Pallé, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Ragazzoni, R., Rando, N., Ratti, F., Rauer, H., Reimers, C., Ribas, I, Santos, N. C., Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Steller, M., Szabó, G. M., Thomas, N., Udry, S., Van Grootel, V., Walton, N. A., and Westerdorff, K.

Abstract

Context. Stellar occultation is a powerful technique that allows the determination of some physical parameters of the occulting object. The result depends on the photometric accuracy, the temporal resolution, and the number of chords obtained. Space telescopes can achieve high photometric accuracy as they are not affected by atmospheric scintillation. Aims. Using ESA’s CHEOPS space telescope, we observed a stellar occultation by the transneptunian object (50000) Quaoar. We compare the obtained chord with previous occultations by this object and determine its astrometry with sub-milliarcsecond precision. Also, we determine upper limits to the presence of a global methane atmosphere on the occulting body. Methods. We predicted and observed a stellar occultation by Quaoar using the CHEOPS space telescope. We measured the occultation light curve from this dataset and determined the dis- and reappearance of the star behind the occulting body. Furthermore, a ground-based telescope in Australia was used to constrain Quaoar’s limb. Combined with results from previous works, these measurements allowed us to obtain a precise position of Quaoar at the occultation time. Results. We present the results obtained from the first stellar occultation by a transneptunian object using a space telescope orbiting Earth; it was the occultation by Quaoar observed on 2020 June 11. We used the CHEOPS light curve to obtain a surface pressure upper limit of 85 nbar for the detection of a global methane atmosphere. Also, combining this observation with a ground-based observation, we fitted Quaoar’s limb to determine its astrometric position with an uncertainty below 1.0 mas. Conclusions. This observation is the first of its kind, and it shall be considered as a proof of concept of stellar occultation observations of transneptunian objects with space telescopes orbiting Earth. Moreover, it shows significant prospects for the James Webb Space Telescope.

Published
2022
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2. Uncovering the true periods of the young sub-Neptunes orbiting TOI-2076

Author

Osborn, H. P., Bonfanti, A., Gandolfi, D., Hedges, C., Leleu, A., Fortier, A., Futyan, D., Gutermann, P., Maxted, P. F. L., Borsato, L., Collins, K. A., da Silva, J. Gomes, Maqueo Chew, Y. Gómez, Hooton, M. J., Lendl, M., Parviainen, H., Salmon, S., Schanche, N., Serrano, L. M., Sousa, S. G., Tuson, A., Ulmer-Moll, S., Van Grootel, V., Wells, R. D., Wilson, T. G., Alibert, Y., Alonso, R., Anglada, G., Asquier, J., Barrado y Navascues, D., Baumjohann, W., Beck, T., Benz, W., Biondi, F., Bonfils, X., Bouchy, F., Brandeker, Alexis, Broeg, C., Bárczy, T., Barros, S. C. C., Cabrera, J., Charnoz, S., Cameron, A. Collier, Csizmadia, S., Davies, M. B., Deleuil, M., Delrez, L., Demory, B.-O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Gillon, M., Gómez-Muñoz, M. A., Güdel, M., Heng, K., Hoyer, S., Isaak, K. G., Kiss, L., Laskar, J., des Etangs, A. Lecavelier, Lovis, C., Magrin, D., Malavolta, L., McCormac, J., Nascimbeni, V, Olofsson, Göran, Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Reimers, C., Ribas, I, Demangeon, O. D. S., Smith, A. M. S., Sabin, L., Santos, N., Scandariato, G., Schroffenegger, U., Schwarz, R. P., Shporer, A., Simon, A. E., Steller, M., Szabó, G. M., Ségransan, D., Thomas, N., Udry, S., Walter, I, Walton, N., Osborn, H. P., Bonfanti, A., Gandolfi, D., Hedges, C., Leleu, A., Fortier, A., Futyan, D., Gutermann, P., Maxted, P. F. L., Borsato, L., Collins, K. A., da Silva, J. Gomes, Maqueo Chew, Y. Gómez, Hooton, M. J., Lendl, M., Parviainen, H., Salmon, S., Schanche, N., Serrano, L. M., Sousa, S. G., Tuson, A., Ulmer-Moll, S., Van Grootel, V., Wells, R. D., Wilson, T. G., Alibert, Y., Alonso, R., Anglada, G., Asquier, J., Barrado y Navascues, D., Baumjohann, W., Beck, T., Benz, W., Biondi, F., Bonfils, X., Bouchy, F., Brandeker, Alexis, Broeg, C., Bárczy, T., Barros, S. C. C., Cabrera, J., Charnoz, S., Cameron, A. Collier, Csizmadia, S., Davies, M. B., Deleuil, M., Delrez, L., Demory, B.-O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Gillon, M., Gómez-Muñoz, M. A., Güdel, M., Heng, K., Hoyer, S., Isaak, K. G., Kiss, L., Laskar, J., des Etangs, A. Lecavelier, Lovis, C., Magrin, D., Malavolta, L., McCormac, J., Nascimbeni, V, Olofsson, Göran, Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Reimers, C., Ribas, I, Demangeon, O. D. S., Smith, A. M. S., Sabin, L., Santos, N., Scandariato, G., Schroffenegger, U., Schwarz, R. P., Shporer, A., Simon, A. E., Steller, M., Szabó, G. M., Ségransan, D., Thomas, N., Udry, S., Walter, I, and Walton, N.

Abstract

Context. TOI-2076 is a transiting three-planet system of sub-Neptunes orbiting a bright (G = 8.9 mag), young (340 ± 80 Myr) K-type star. Although a validated planetary system, the orbits of the two outer planets were unconstrained as only two non-consecutive transits were seen in TESS photometry. This left 11 and 7 possible period aliases for each. Aims. To reveal the true orbits of these two long-period planets, precise photometry targeted on the highest-probability period aliases is required. Long-term monitoring of transits in multi-planet systems can also help constrain planetary masses through TTV measurements. Methods. We used the MonoTools package to determine which aliases to follow, and then performed space-based and ground-based photometric follow-up of TOI-2076 c and d with CHEOPS, SAINT-EX, and LCO telescopes. Results. CHEOPS observations revealed a clear detection for TOI-2076 c at d, and allowed us to rule out three of the most likely period aliases for TOI-2076 d. Ground-based photometry further enabled us to rule out remaining aliases and confirm the P = 35.12537 ± 0.00067 d alias. These observations also improved the radius precision of all three sub-Neptunes to 2.518 ± 0.036, 3.497 ± 0.043, and 3.232 ± 0.063 R⊕. Our observations also revealed a clear anti-correlated TTV signal between planets b and c likely caused by their proximity to the 2:1 resonance, while planets c and d appear close to a 5:3 period commensurability, although model degeneracy meant we were unable to retrieve robust TTV masses. Their inflated radii, likely due to extended H-He atmospheres, combined with low insolation makes all three planets excellent candidates for future comparative transmission spectroscopy with JWST.

Published
2022
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3. Analysis of Early Science observations with the CHaracterising ExOPlanets Satellite (CHEOPS) using pycheops

Author

Maxted, P. F. L., Ehrenreich, D., Wilson, T. G., Alibert, Y., Collier Cameron, A., Hoyer, S., Sousa, S. G., Olofsson, Göran, Bekkelien, A., Deline, A., Delrez, L., Bonfanti, A., Borsato, L., Alonso, R., Anglada Escudé, G., Barrado, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Biondi, F., Bonfils, X., Brandeker, Alexis, Broeg, C., Bárczy, T., Cabrera, J., Charnoz, S., Corral Van Damme, C., Csizmadia, Sz, Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Erikson, A., Florén, Hans Gustav, Fortier, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Gillon, M., Guedel, M., Guterman, P., Heng, K., Isaak, K. G., Kiss, L., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lovis, C., Magrin, D., Nascimbeni, V., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Pozuelos, F. J., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Reimers, C., Ribas, I., Salmon, S., Santos, N. C., Scandariato, G., Simon, A. E., Smith, A. M. S., Steller, M., Swayne, M., Szabó, Gy. M., Ségransan, D., Thomas, N., Udry, S., Van Grootel, V., Walton, N. A., Maxted, P. F. L., Ehrenreich, D., Wilson, T. G., Alibert, Y., Collier Cameron, A., Hoyer, S., Sousa, S. G., Olofsson, Göran, Bekkelien, A., Deline, A., Delrez, L., Bonfanti, A., Borsato, L., Alonso, R., Anglada Escudé, G., Barrado, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Biondi, F., Bonfils, X., Brandeker, Alexis, Broeg, C., Bárczy, T., Cabrera, J., Charnoz, S., Corral Van Damme, C., Csizmadia, Sz, Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Erikson, A., Florén, Hans Gustav, Fortier, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Gillon, M., Guedel, M., Guterman, P., Heng, K., Isaak, K. G., Kiss, L., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lovis, C., Magrin, D., Nascimbeni, V., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Pozuelos, F. J., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Reimers, C., Ribas, I., Salmon, S., Santos, N. C., Scandariato, G., Simon, A. E., Smith, A. M. S., Steller, M., Swayne, M., Szabó, Gy. M., Ségransan, D., Thomas, N., Udry, S., Van Grootel, V., and Walton, N. A.

Abstract

CHEOPS (CHaracterising ExOPlanet Satellite) is an ESA S-class mission that observes bright stars at high cadence from low-Earth orbit. The main aim of the mission is to characterize exoplanets that transit nearby stars using ultrahigh precision photometry. Here, we report the analysis of transits observed by CHEOPS during its Early Science observing programme for four well-known exoplanets: GJ 436 b, HD 106315 b, HD 97658 b, and GJ 1132 b. The analysis is done using pycheops, an open-source software package we have developed to easily and efficiently analyse CHEOPS light-curve data using state-of-the-art techniques that are fully described herein. We show that the precision of the transit parameters measured using CHEOPS is comparable to that from larger space telescopes such as Spitzer Space Telescope and Kepler. We use the updated planet parameters from our analysis to derive new constraints on the internal structure of these four exoplanets.

Published
2022
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4. Transit timing variations of AU Microscopii b and c

Author

Szabó, Gy. M., Garai, Z., Brandeker, Alexis, Gandolfi, D., Wilson, T. G., Deline, A., Olofsson, Göran, Fortier, A., Queloz, D., Borsato, L., Kiefer, F., Lecavelier des Etangs, A., Lendl, M., Serrano, L. M., Sulis, S., Ulmer Moll, S., Van Grootel, V., Alibert, Y., Alonso, R., Anglada, G., Bárczy, T., Barrado y Navascues, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Bonfanti, A., Bonfils, X., Broeg, C., Cabrera, J., Charnoz, S., Collier Cameron, A., Csizmadia, Sz., Davies, M. B., Deleuil, M., Delrez, L., Demangeon, O., Demory, B.-O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Gillon, M., Güdel, M., Heng, K., Hoyer, S., Isaak, K. G., Kiss, L. L., Laskar, J., Lovis, C., Magrin, D., Maxted, P. F. L., Mecina, M., Nascimbeni, V., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Sarajlic, M., Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Thomas, N., Udry, S., Verrecchia, F., Walton, N., Wolter, D., Szabó, Gy. M., Garai, Z., Brandeker, Alexis, Gandolfi, D., Wilson, T. G., Deline, A., Olofsson, Göran, Fortier, A., Queloz, D., Borsato, L., Kiefer, F., Lecavelier des Etangs, A., Lendl, M., Serrano, L. M., Sulis, S., Ulmer Moll, S., Van Grootel, V., Alibert, Y., Alonso, R., Anglada, G., Bárczy, T., Barrado y Navascues, D., Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Bonfanti, A., Bonfils, X., Broeg, C., Cabrera, J., Charnoz, S., Collier Cameron, A., Csizmadia, Sz., Davies, M. B., Deleuil, M., Delrez, L., Demangeon, O., Demory, B.-O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Gillon, M., Güdel, M., Heng, K., Hoyer, S., Isaak, K. G., Kiss, L. L., Laskar, J., Lovis, C., Magrin, D., Maxted, P. F. L., Mecina, M., Nascimbeni, V., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Sarajlic, M., Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Thomas, N., Udry, S., Verrecchia, F., Walton, N., and Wolter, D.

Abstract

Here we report large-amplitude transit timing variations (TTVs) for AU Microcopii b and c as detected in combined TESS (2018, 2020) and CHEOPS (2020, 2021) transit observations. AU Mic is a young planetary system with a debris disk and two transiting warm Neptunes. A TTV on the order of several minutes was previously reported for AU Mic b, which was suggested to be an outcome of mutual perturbations between the planets in the system. In 2021, we observed AU Mic b (five transits) and c (three transits) with the CHEOPS space telescope to follow-up the TTV of AU Mic b and possibly detect a TTV for AU Mic c. When analyzing TESS and CHEOPS 2020-2021 measurements together, we find that a prominent TTV emerges with a full span of >= 23 min between the two TTV extrema. Assuming that the period change results from a periodic process -such as mutual perturbations- we demonstrate that the times of transits in the summer of 2022 are expected to be 30-85 min later than predicted by the available linear ephemeris.

Published
2022
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5. CHEOPS geometric albedo of the hot Jupiter HD 209458 b

Author

Brandeker, Alexis, Heng, K., Lendl, M., Patel, Jayshil Ashokkumar, Morris, B. M., Broeg, C., Guterman, P., Beck, M., Maxted, P. F. L., Demangeon, O., Delrez, L., Demory, B-O, Kitzmann, D., Santos, N. C., Singh, V, Alibert, Y., Alonso, R., Anglada, G., Barczy, T., Barrado y Navascues, D., Barros, S. C. C., Baumjohann, W., Beck, T., Benz, W., Billot, N., Bonfils, X., Bruno, G., Cabrera, J., Charnoz, S., Collier Cameron, A., van Damme, C. Corral, Csizmadia, Sz, Davies, M. B., Deleuil, M., Deline, A., Ehrenreich, D., Erikson, A., Farinato, J., Fortier, A., Fossati, L., Fridlund, M., Gandolfi, D., Gillon, M., Guedel, M., Hoyer, S., Isaak, K. G., Kiss, L., Laskar, J., Lecavelier des Etangs, A., Lovis, C., Luntzer, A., Magrin, D., Nascimbeni, V, Olofsson, Göran, Ottensamer, R., Pagano, I, Pallé, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I, Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Szabó, G. M., Thomas, N., Udry, S., Van Grootel, V., Walton, N., Wolter, D., Brandeker, Alexis, Heng, K., Lendl, M., Patel, Jayshil Ashokkumar, Morris, B. M., Broeg, C., Guterman, P., Beck, M., Maxted, P. F. L., Demangeon, O., Delrez, L., Demory, B-O, Kitzmann, D., Santos, N. C., Singh, V, Alibert, Y., Alonso, R., Anglada, G., Barczy, T., Barrado y Navascues, D., Barros, S. C. C., Baumjohann, W., Beck, T., Benz, W., Billot, N., Bonfils, X., Bruno, G., Cabrera, J., Charnoz, S., Collier Cameron, A., van Damme, C. Corral, Csizmadia, Sz, Davies, M. B., Deleuil, M., Deline, A., Ehrenreich, D., Erikson, A., Farinato, J., Fortier, A., Fossati, L., Fridlund, M., Gandolfi, D., Gillon, M., Guedel, M., Hoyer, S., Isaak, K. G., Kiss, L., Laskar, J., Lecavelier des Etangs, A., Lovis, C., Luntzer, A., Magrin, D., Nascimbeni, V, Olofsson, Göran, Ottensamer, R., Pagano, I, Pallé, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I, Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Szabó, G. M., Thomas, N., Udry, S., Van Grootel, V., Walton, N., and Wolter, D.

Abstract

We report the detection of the secondary eclipse of the hot Jupiter HD 209458 b in optical/visible light using the CHEOPS space telescope. Our measurement of 20.4−3.3+3.2 parts per million translates into a geometric albedo of Ag = 0.096 ± 0.016. The previously estimated dayside temperature of about 1500 K implies that our geometric albedo measurement consists predominantly of reflected starlight and is largely uncontaminated by thermal emission. This makes the present result one of the most robust measurements of Ag for any exoplanet. Our calculations of the bandpass-integrated geometric albedo demonstrate that the measured value of Ag is consistent with a cloud-free atmosphere, where starlight is reflected via Rayleigh scattering by hydrogen molecules, and the water and sodium abundances are consistent with stellar metallicity. We predict that the bandpass-integrated TESS geometric albedo is too faint to detect and that a phase curve of HD 209458 b observed by CHEOPS would have a distinct shape associated with Rayleigh scattering if the atmosphere is indeed cloud free.

Published
2022
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6. The CHEOPS mission

Author

Benz, W., Broeg, C., Fortier, A., Rando, N., Beck, T., Beck, M., Queloz, D., Ehrenreich, D., Maxted, P. F. L., Isaak, K. G., Billot, N., Alibert, Y., Alonso, R., Antonio, C., Asquier, J., Bandy, T., Barczy, T., Barrado, D., Barros, S. C. C., Baumjohann, W., Bekkelien, A., Bergomi, M., Biondi, F., Bonfils, X., Borsato, L., Brandeker, Alexis, Busch, M.-D., Cabrera, J., Cessa, V., Charnoz, S., Chazelas, B., Collier Cameron, A., Corral Van Damme, C., Cortes, D., Davies, M. B., Deleuil, M., Deline, A., Delrez, L., Demangeon, O., Demory, B. O., Erikson, A., Farinato, J., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Garcia Munoz, A., Gillon, M., Guterman, P., Gutierrez, A., Hasiba, J., Heng, K., Hernandez, E., Hoyer, S., Kiss, L. L., Kovacs, Z., Kuntzer, T., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lopez, A., Lora, I., Lovis, C., Lueftinger, T., Magrin, D., Malvasio, L., Marafatto, L., Michaelis, H., de Miguel, D., Modrego, D., Munari, M., Nascimbeni, V., Olofsson, Göran, Ottacher, H., Ottensamer, R., Pagano, I., Palacios, R., Pall, E., Peter, G., Piazza, D., Piotto, G., Pizarro, A., Pollaco, D., Ragazzoni, R., Ratti, F., Rauer, H., Ribas, I., Rieder, M., Rohlfs, R., Safa, F., Salatti, M., Santos, N. C., Scandariato, G., Segransan, D., Simon, A. E., Smith, A. M. S., Sordet, M., Sousa, S. G., Steller, M., Szabo, G. M., Szoke, J., Thomas, N., Tschentscher, M., Udry, S., Van Grootel, V., Viotto, V., Walter, I., Walton, N. A., Wildi, F., Wolter, D., Benz, W., Broeg, C., Fortier, A., Rando, N., Beck, T., Beck, M., Queloz, D., Ehrenreich, D., Maxted, P. F. L., Isaak, K. G., Billot, N., Alibert, Y., Alonso, R., Antonio, C., Asquier, J., Bandy, T., Barczy, T., Barrado, D., Barros, S. C. C., Baumjohann, W., Bekkelien, A., Bergomi, M., Biondi, F., Bonfils, X., Borsato, L., Brandeker, Alexis, Busch, M.-D., Cabrera, J., Cessa, V., Charnoz, S., Chazelas, B., Collier Cameron, A., Corral Van Damme, C., Cortes, D., Davies, M. B., Deleuil, M., Deline, A., Delrez, L., Demangeon, O., Demory, B. O., Erikson, A., Farinato, J., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Garcia Munoz, A., Gillon, M., Guterman, P., Gutierrez, A., Hasiba, J., Heng, K., Hernandez, E., Hoyer, S., Kiss, L. L., Kovacs, Z., Kuntzer, T., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lopez, A., Lora, I., Lovis, C., Lueftinger, T., Magrin, D., Malvasio, L., Marafatto, L., Michaelis, H., de Miguel, D., Modrego, D., Munari, M., Nascimbeni, V., Olofsson, Göran, Ottacher, H., Ottensamer, R., Pagano, I., Palacios, R., Pall, E., Peter, G., Piazza, D., Piotto, G., Pizarro, A., Pollaco, D., Ragazzoni, R., Ratti, F., Rauer, H., Ribas, I., Rieder, M., Rohlfs, R., Safa, F., Salatti, M., Santos, N. C., Scandariato, G., Segransan, D., Simon, A. E., Smith, A. M. S., Sordet, M., Sousa, S. G., Steller, M., Szabo, G. M., Szoke, J., Thomas, N., Tschentscher, M., Udry, S., Van Grootel, V., Viotto, V., Walter, I., Walton, N. A., Wildi, F., and Wolter, D.

Abstract

The CHaracterising ExOPlanet Satellite (CHEOPS) was selected on October 19, 2012, as the first small mission (S-mission) in the ESA Science Programme and successfully launched on December 18, 2019, as a secondary passenger on a Soyuz-Fregat rocket from Kourou, French Guiana. CHEOPS is a partnership between ESA and Switzerland with important contributions by ten additional ESA Member States. CHEOPS is the first mission dedicated to search for transits of exoplanets using ultrahigh precision photometry on bright stars already known to host planets. As a follow-up mission, CHEOPS is mainly dedicated to improving, whenever possible, existing radii measurements or provide first accurate measurements for a subset of those planets for which the mass has already been estimated from ground-based spectroscopic surveys. The expected photometric precision will also allow CHEOPS to go beyond measuring only transits and to follow phase curves or to search for exo-moons, for example. Finally, by unveiling transiting exoplanets with high potential for in-depth characterisation, CHEOPS will also provide prime targets for future instruments suited to the spectroscopic characterisation of exoplanetary atmospheres. To reach its science objectives, requirements on the photometric precision and stability have been derived for stars with magnitudes ranging from 6 to 12 in the V band. In particular, CHEOPS shall be able to detect Earth-size planets transiting G5 dwarf stars (stellar radius of 0.9R(circle dot)) in the magnitude range 6 <= V <= 9 by achieving a photometric precision of 20 ppm in 6 hours of integration time. In the case of K-type stars (stellar radius of 0.7R(circle dot)) of magnitude in the range 9 <= V <= 12, CHEOPS shall be able to detect transiting Neptune-size planets achieving a photometric precision of 85 ppm in 3 hours of integration time. This precision has to be maintained over continuous periods of observation for up to 48 hours. This precision and stab

Published
2021
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7. The EBLM project – VIII. First results for M-dwarf mass, radius, and effective temperature measurements using CHEOPS light curves

Author

Swayne, M., Maxted, P. F. L., Triaud, A. H. M. J., Sousa, S. G., Broeg, C., Florén, Hans Gustav Axel, Guterman, P., Simon, A. E., Boisse, I., Bonfanti, A., Martin, D., Santerne, A., Salmon, S., Standing, M. R., Van Grootel, V., Wilson, T. G., Alibert, Y., Alonso, R., Anglada Escudé, G., Asquier, J., Bárczy, T., Barrado, D., Barros, S. C. C., Battley, M., Baumjohann, W., Beck, M., Beck, T., Bekkelien, A., Benz, W., Billot, N., Bonfils, X., Brandeker, Alexis, Busch, M.-D., Cabrera, J., Charnoz, S., Collier Cameron, A., Csizmadia, Sz., Davies, M. B., Deleuil, M., Deline, A., Delrez, L., Demangeon, O. D. S., Demory, B.-O., Dransfield, G., Ehrenreich, D., Erikson, A., Fortier, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Gillon, M., Guedel, M., Hébrard, G., Heidari, N., Hellier, C., Heng, K., Hobson, M., Hoyer, S., Isaak, K. G., Kiss, L., Kunovac Hodžić, V., Lalitha, S., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lovis, C., Magrin, D., Marafatto, L., McCormac, J., Miller, N., Nascimbeni, V., Olofsson, Göran, Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Scandariato, G., Ségransan, D., Smith, A. M. S., Steinberger, M., Steller, M., Szabó, Gy. M., Thomas, N., Udry, S., Walter, I., Walton, N. A., Willett, E., Swayne, M., Maxted, P. F. L., Triaud, A. H. M. J., Sousa, S. G., Broeg, C., Florén, Hans Gustav Axel, Guterman, P., Simon, A. E., Boisse, I., Bonfanti, A., Martin, D., Santerne, A., Salmon, S., Standing, M. R., Van Grootel, V., Wilson, T. G., Alibert, Y., Alonso, R., Anglada Escudé, G., Asquier, J., Bárczy, T., Barrado, D., Barros, S. C. C., Battley, M., Baumjohann, W., Beck, M., Beck, T., Bekkelien, A., Benz, W., Billot, N., Bonfils, X., Brandeker, Alexis, Busch, M.-D., Cabrera, J., Charnoz, S., Collier Cameron, A., Csizmadia, Sz., Davies, M. B., Deleuil, M., Deline, A., Delrez, L., Demangeon, O. D. S., Demory, B.-O., Dransfield, G., Ehrenreich, D., Erikson, A., Fortier, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Gillon, M., Guedel, M., Hébrard, G., Heidari, N., Hellier, C., Heng, K., Hobson, M., Hoyer, S., Isaak, K. G., Kiss, L., Kunovac Hodžić, V., Lalitha, S., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lovis, C., Magrin, D., Marafatto, L., McCormac, J., Miller, N., Nascimbeni, V., Olofsson, Göran, Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Scandariato, G., Ségransan, D., Smith, A. M. S., Steinberger, M., Steller, M., Szabó, Gy. M., Thomas, N., Udry, S., Walter, I., Walton, N. A., and Willett, E.

Abstract

The accuracy of theoretical mass, radius, and effective temperature values for M-dwarf stars is an active topic of debate. Differences between observed and theoretical values have raised the possibility that current theoretical stellar structure and evolution models are inaccurate towards the low-mass end of the main sequence. To explore this issue, we use the CHEOPS satellite to obtain high-precision light curves of eclipsing binaries with low-mass stellar companions. We use these light curves combined with the spectroscopic orbit for the solar-type companion to measure the mass, radius, and effective temperature of the M-dwarf star. Here, we present the analysis of three eclipsing binaries. We use the PYCHEOPS data analysis software to fit the observed transit and eclipse events of each system. Two of our systems were also observed by the TESS satellite – we similarly analyse these light curves for comparison. We find consistent results between CHEOPS and TESS, presenting three stellar radii and two stellar effective temperature values of low-mass stellar objects. These initial results from our on-going observing programme with CHEOPS show that we can expect to have ∼24 new mass, radius, and effective temperature measurements for very low-mass stars within the next few years.

Published
2021
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8. The changing face of AU Mic b : stellar spots, spin-orbit commensurability, and transit timing variations as seen by CHEOPS and TESS

Author

Szabo, Gy M., Gandolfi, D., Brandeker, Alexis, Csizmadia, Sz, Garai, Z., Billot, N., Broeg, C., Ehrenreich, D., Fortier, A., Fossati, L., Hoyer, S., Kiss, L., Lecavelier des Etangs, A., Maxted, P. F. L., Ribas, I., Alibert, Y., Alonso, R., Anglada Escude, G., Barczy, T., Barros, S. C. C., Barrado, D., Baumjohann, W., Beck, M., Beck, T., Bekkelien, A., Bonfils, X., Benz, W., Borsato, L., Busch, M.-D., Cabrera, J., Charnoz, S., Collier Cameron, A., Corral Van Damme, C., Davies, M. B., Delrez, L., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Erikson, A., Fridlund, M., Futyan, D., Garcia Munoz, A., Gillon, M., Guedel, M., Guterman, P., Heng, K., Isaak, K. G., Lacedelli, G., Laskar, J., Lendl, M., Lovis, C., Luntzer, A., Magrin, D., Nascimbeni, V., Olofsson, Göran, Osborn, H. P., Ottensamer, R., Pagano, I., Palle, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Santos, N. C., Scandariato, G., Segransan, D., Serrano, L. M., Sicilia, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Thomas, N., Udry, S., Van Grootel, V., Walton, N. A., Wilson, T. G., Szabo, Gy M., Gandolfi, D., Brandeker, Alexis, Csizmadia, Sz, Garai, Z., Billot, N., Broeg, C., Ehrenreich, D., Fortier, A., Fossati, L., Hoyer, S., Kiss, L., Lecavelier des Etangs, A., Maxted, P. F. L., Ribas, I., Alibert, Y., Alonso, R., Anglada Escude, G., Barczy, T., Barros, S. C. C., Barrado, D., Baumjohann, W., Beck, M., Beck, T., Bekkelien, A., Bonfils, X., Benz, W., Borsato, L., Busch, M.-D., Cabrera, J., Charnoz, S., Collier Cameron, A., Corral Van Damme, C., Davies, M. B., Delrez, L., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Erikson, A., Fridlund, M., Futyan, D., Garcia Munoz, A., Gillon, M., Guedel, M., Guterman, P., Heng, K., Isaak, K. G., Lacedelli, G., Laskar, J., Lendl, M., Lovis, C., Luntzer, A., Magrin, D., Nascimbeni, V., Olofsson, Göran, Osborn, H. P., Ottensamer, R., Pagano, I., Palle, E., Peter, G., Piazza, D., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Santos, N. C., Scandariato, G., Segransan, D., Serrano, L. M., Sicilia, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Thomas, N., Udry, S., Van Grootel, V., Walton, N. A., and Wilson, T. G.

Abstract

AU Mic is a young planetary system with a resolved debris disc showing signs of planet formation and two transiting warm Neptunes near mean-motion resonances. Here we analyse three transits of AU Mic b observed with the CHaracterising ExOPlanet Satellite (CHEOPS), supplemented with sector 1 and 27 Transiting Exoplanet Survey Satellite (TESS) photometry, and the All-Sky Automated Survey from the ground. The refined orbital period of AU Mic b is 8.462995 +/- 0.000003 d, whereas the stellar rotational period is P-rot = 4.8367 +/- 0.0006 d. The two periods indicate a 7:4 spin-orbit commensurability at a precision of 0.1%. Therefore, all transits are observed in front of one of the four possible stellar central longitudes. This is strongly supported by the observation that the same complex star-spot pattern is seen in the second and third CHEOPS visits that were separated by four orbits (and seven stellar rotations). Using a bootstrap analysis we find that flares and star spots reduce the accuracy of transit parameters by up to 10% in the planet-to-star radius ratio and the accuracy on transit time by 3-4 min. Nevertheless, occulted stellar spot features independently confirm the presence of transit timing variations (TTVs) with an amplitude of at least 4 min. We find that the outer companion, AU Mic c, may cause the observed TTVs.

Published
2021
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9. Exploiting timing capabilities of the CHEOPS mission with warm-Jupiter planets

Author

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

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 by 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 ∼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.

Published
2021
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10. A search for transiting planets around hot subdwarfs I. Methods and performance tests on light curves from Kepler, K2, TESS, and CHEOPS

Author

Van Grootel, V., Pozuelos, F. J., Thuillier, A., Charpinet, S., Delrez, L., Beck, M., Fortier, A., Hoyer, S., Sousa, S. G., Barlow, B. N., Billot, N., Dévora-Pajares, M., Østensen, R. H., Alibert, Y., Alonso, R., Anglada Escudé, G., Asquier, J., Barrado, D., Barros, S. C. C., Baumjohann, W., Beck, T., Bekkelien, A., Benz, W., Bonfils, X., Brandeker, Alexis, Broeg, C., Bruno, G., Bárczy, T., Cabrera, J., Cameron, A. C., Charnoz, S., Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B-O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Gillon, M., Guedel, M., Heng, K., Isaak, K. G., Kiss, L., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lovis, C., Magrin, D., Maxted, P. F. L., Mecina, M., Mustill, A. J., Nascimbeni, V., Olofsson, Göran, Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Plesseria, J-Y., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Scandariato, G., Ségransan, D., Silvotti, R., Simon, A. E., Smith, A. M. S., Steller, M., Szabó, G. M., Thomas, N., Udry, S., Viotto, V., Walton, N. A., Westerdorff, K., Wilson, T. G., Van Grootel, V., Pozuelos, F. J., Thuillier, A., Charpinet, S., Delrez, L., Beck, M., Fortier, A., Hoyer, S., Sousa, S. G., Barlow, B. N., Billot, N., Dévora-Pajares, M., Østensen, R. H., Alibert, Y., Alonso, R., Anglada Escudé, G., Asquier, J., Barrado, D., Barros, S. C. C., Baumjohann, W., Beck, T., Bekkelien, A., Benz, W., Bonfils, X., Brandeker, Alexis, Broeg, C., Bruno, G., Bárczy, T., Cabrera, J., Cameron, A. C., Charnoz, S., Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B-O., Ehrenreich, D., Erikson, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Gillon, M., Guedel, M., Heng, K., Isaak, K. G., Kiss, L., Laskar, J., Lecavelier des Etangs, A., Lendl, M., Lovis, C., Magrin, D., Maxted, P. F. L., Mecina, M., Mustill, A. J., Nascimbeni, V., Olofsson, Göran, Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Plesseria, J-Y., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Santos, N. C., Scandariato, G., Ségransan, D., Silvotti, R., Simon, A. E., Smith, A. M. S., Steller, M., Szabó, G. M., Thomas, N., Udry, S., Viotto, V., Walton, N. A., Westerdorff, K., and Wilson, T. G.

Abstract

Context. Hot subdwarfs experienced strong mass loss on the red giant branch (RGB) and are now hot and small He-burning objects. These stars constitute excellent opportunities for addressing the question of the evolution of exoplanetary systems directly after the RGB phase of evolution. Aims. In this project we aim to perform a transit survey in all available light curves of hot subdwarfs from space-based telescopes (Kepler, K2, TESS, and CHEOPS) with our custom-made pipeline SHERLOCK in order to determine the occurrence rate of planets around these stars as a function of orbital period and planetary radius. We also aim to determine whether planets that were previously engulfed in the envelope of their red giant host star can survive, even partially, as a planetary remnant. Methods. For this first paper, we performed injection-and-recovery tests of synthetic transits for a selection of representative Kepler, K2, and TESS light curves to determine which transiting bodies in terms of object radius and orbital period we will be able to detect with our tools. We also provide estimates for CHEOPS data, which we analyzed with the pycheops package. Results. Transiting objects with a radius ≲1.0 R⊕ can be detected in most of the Kepler, K2, and CHEOPS targets for the shortest orbital periods (1 d and shorter), reaching values as low as ~0.3 R⊕ in the best cases. Sub-Earth-sized bodies are only reached for the brightest TESS targets and for those that were observed in a significant number of sectors. We also give a series of representative results for larger planets at greater distances, which strongly depend on the target magnitude and on the length and quality of the data. Conclusions. The TESS sample will provide the most important statistics for the global aim of measuring the planet occurrence rate around hot subdwarfs. The Kepler, K2, and CHEOPS data will allow us to search for planetary remnants, that is, very close and small (possibly disintegrating) objects.

Published
2021
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11. Six transiting planets and a chain of Laplace resonances in TOI-178

Author

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., Cabrera, J., Delrez, L., Acton, J. S., Adibekyan, V., Allart, R., Allende Prieto, C., Alonso, R., Alves, D., Anderson, D. R., Angerhausen, D., Anglada Escude, G., Asquier, J., Barrado, D., Barros, S. C. C., Baumjohann, W., Bayliss, D., Beck, M., Beck, T., Bekkelien, A., Benz, W., Billot, N., Bonfanti, A., Bonfils, X., Bouchy, F., Bourrier, V., Boue, G., Brandeker, Alexis, Broeg, C., Buder, M., Burdanov, A., Burleigh, M. R., Barczy, T., Cameron, A. C., Chamberlain, S., Charnoz, S., Cooke, B. F., Corral Van Damme, C., Correia, A. C. M., Cristiani, S., Damasso, M., Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Di Marcantonio, P., Di Persio, G., Dumusque, X., Ehrenreich, D., Erikson, A., Figueira, P., Fortier, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Garcia Munoz, A., Garcia, L. J., Gill, S., Zapatero Osorio, M. R., Gillen, E., Gillon, M., Goad, M. R., Gonzalez Hernandez, J., Guedel, M., Haldemann, J., Henderson, B., Heng, K., Hogan, A. E., Isaak, K., Jehin, E., Jenkins, J. S., Jordan, A., Kiss, L., Kristiansen, M. H., Lam, K., Lavie, B., Lecavelier des Etangs, A., Lendl, M., Lillo-Box, J., Lo Curto, G., Magrin, D., Martins, C. J. A. P., Maxted, P. F. L., McCormac, J., Mehner, A., Micela, G., Molaro, P., Moyano, M., Murray, C. A., Nascimbeni, V., Nunes, N. J., Olofsson, Göran, Osborn, H. P., Oshagh, M., Ottensamer, R., Pagano, I., Palle, E., Pedersen, P. P., Pepe, F. A., Persson, C. M., Peter, G., Piotto, G., Polenta, G., Pollacco, D., Poretti, E., Pozuelos, F. J., Queloz, D., Ragazzoni, R., Rando, N., Ratti, F., Rauer, H., Raynard, L., Rebolo, R., Reimers, C., Ribas, I., Santos, N. C., Scandariato, G., Schneider, J., Sebastian, D., Sestovic, M., Simon, A. E., Smith, A. M. S., Sousa, S. G., Sozzetti, A., Steller, M., Suarez Mascareno, A., Szabo, Gy M., Segransan, D., Thomas, N., Thompson, S., Tilbrook, R. H., Triaud, A., Turner, O., Udry, S., Van Grootel, V., Venus, H., Verrecchia, F., Vines, J., Walton, N. A., West, R. G., Wheatley, P. J., Wolter, D., 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., Cabrera, J., Delrez, L., Acton, J. S., Adibekyan, V., Allart, R., Allende Prieto, C., Alonso, R., Alves, D., Anderson, D. R., Angerhausen, D., Anglada Escude, G., Asquier, J., Barrado, D., Barros, S. C. C., Baumjohann, W., Bayliss, D., Beck, M., Beck, T., Bekkelien, A., Benz, W., Billot, N., Bonfanti, A., Bonfils, X., Bouchy, F., Bourrier, V., Boue, G., Brandeker, Alexis, Broeg, C., Buder, M., Burdanov, A., Burleigh, M. R., Barczy, T., Cameron, A. C., Chamberlain, S., Charnoz, S., Cooke, B. F., Corral Van Damme, C., Correia, A. C. M., Cristiani, S., Damasso, M., Davies, M. B., Deleuil, M., Demangeon, O. D. S., Demory, B.-O., Di Marcantonio, P., Di Persio, G., Dumusque, X., Ehrenreich, D., Erikson, A., Figueira, P., Fortier, A., Fossati, L., Fridlund, M., Futyan, D., Gandolfi, D., Garcia Munoz, A., Garcia, L. J., Gill, S., Zapatero Osorio, M. R., Gillen, E., Gillon, M., Goad, M. R., Gonzalez Hernandez, J., Guedel, M., Haldemann, J., Henderson, B., Heng, K., Hogan, A. E., Isaak, K., Jehin, E., Jenkins, J. S., Jordan, A., Kiss, L., Kristiansen, M. H., Lam, K., Lavie, B., Lecavelier des Etangs, A., Lendl, M., Lillo-Box, J., Lo Curto, G., Magrin, D., Martins, C. J. A. P., Maxted, P. F. L., McCormac, J., Mehner, A., Micela, G., Molaro, P., Moyano, M., Murray, C. A., Nascimbeni, V., Nunes, N. J., Olofsson, Göran, Osborn, H. P., Oshagh, M., Ottensamer, R., Pagano, I., Palle, E., Pedersen, P. P., Pepe, F. A., Persson, C. M., Peter, G., Piotto, G., Polenta, G., Pollacco, D., Poretti, E., Pozuelos, F. J., Queloz, D., Ragazzoni, R., Rando, N., Ratti, F., Rauer, H., Raynard, L., Rebolo, R., Reimers, C., Ribas, I., Santos, N. C., Scandariato, G., Schneider, J., Sebastian, D., Sestovic, M., Simon, A. E., Smith, A. M. S., Sousa, S. G., Sozzetti, A., Steller, M., Suarez Mascareno, A., Szabo, Gy M., Segransan, D., Thomas, N., Thompson, S., Tilbrook, R. H., Triaud, A., Turner, O., Udry, S., Van Grootel, V., Venus, H., Verrecchia, F., Vines, J., Walton, N. A., West, R. G., Wheatley, P. J., and Wolter, D.

Abstract

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) 1.152-0.070+0.073 to 2.87(-0.13)(+0.14) 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) 1.02-0.23+0.28 to 0.177(-0.061)(+0.055) 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 stud

Published
2021
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12. CHEOPS observations of the HD 108236 planetary system : a fifth planet, improved ephemerides, and planetary radii

Author

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., 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., Szabo, 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., Barczy, T., Barrado, D., Barragan, O., Baumjohann, W., Beck, T., Bekkelien, A., Bergomi, M., Brandeker, Alexis, Busch, M.-D., Cessa, V., Charnoz, S., Chazelas, B., Corral Van Damme, C., Demory, B.-O., Erikson, A., Farinato, J., Futyan, D., Garcia Munoz, A., Gillon, M., Guedel, M., Guterman, P., Hasiba, J., Heng, K., Hernandez, E., Kiss, L., Kuntzer, T., Laskar, J., Lecavelier des Etangs, A., Lovis, C., Magrin, D., Malvasio, L., Marafatto, L., Michaelis, H., Munari, M., Olofsson, Göran, Ottacher, H., Ottensamer, R., Pagano, I., Palle, 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., Segransan, D., Simon, A. E., Smith, A. M. S., Sordet, M., Steller, M., Thomas, N., Tschentscher, M., Van Eylen, V., Viotto, V., Walter, I., Walton, N. A., Wildi, F., Wolter, D., 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., 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., Szabo, 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., Barczy, T., Barrado, D., Barragan, O., Baumjohann, W., Beck, T., Bekkelien, A., Bergomi, M., Brandeker, Alexis, Busch, M.-D., Cessa, V., Charnoz, S., Chazelas, B., Corral Van Damme, C., Demory, B.-O., Erikson, A., Farinato, J., Futyan, D., Garcia Munoz, A., Gillon, M., Guedel, M., Guterman, P., Hasiba, J., Heng, K., Hernandez, E., Kiss, L., Kuntzer, T., Laskar, J., Lecavelier des Etangs, A., Lovis, C., Magrin, D., Malvasio, L., Marafatto, L., Michaelis, H., Munari, M., Olofsson, Göran, Ottacher, H., Ottensamer, R., Pagano, I., Palle, 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., Segransan, D., Simon, A. E., Smith, A. M. S., Sordet, M., Steller, M., Thomas, N., Tschentscher, M., Van Eylen, V., Viotto, V., Walter, I., Walton, N. A., Wildi, F., and Wolter, D.

Abstract

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-star = 0.877 +/- 0.008 R-circle dot, M-star = 0.869(-0.048)(+0.050)M(circle dot), 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-circle plus 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

Published
2021
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13. The PLATO 2.0 mission

Author

Rauer, H., Catala, C., Aerts, C., Appourchaux, T., Benz, W., Brandeker, Aexis, Christensen-Dalsgaard, J., Deleuil, M., Gizon, L., Goupil, M. -J, Guedel, M., Janot-Pacheco, E., Mas-Hesse, M., Pagano, I., Piotto, G., Pollacco, D., Santos, N. C., Smith, A., Suarez, J. -C, Szabo, R., Udry, S., Adibekyan, V., Alibert, Y., Almenara, J. -M, Maro-Seoane, P. A., Ammler-von Eiff, M., Asplund, M., Antonello, E., Barnes, S., Baudin, F., Belkacem, K., Bergemann, M., Bihain, G., Birch, A. C., Bonfils, X., Boisse, I., Bonomo, A. S., Borsa, F., Brandao, I. M., Brocato, E., Brun, S., Burleigh, M., Burston, R., Cabrera, J., Cassisi, S., Chaplin, W., Charpinet, S., Chiappini, C., Church, R. P., Csizmadia, Sz., Cunha, M., Damasso, M., Davies, M. B., Deeg, H. J., Diaz, R. F., Dreizler, S., Dreyer, C., Eggenberger, P., Ehrenreich, D., Eigmueller, P., Erikson, A., Farmer, R., Feltzing, S., de Oliveira Fialho, F., Figueira, P., Forveille, T., Fridlund, M., Garcia, R. A., Giommi, P., Giuffrida, G., Godolt, M., Gomes da Silva, J., Granzer, T., Grenfell, J. L., Grotsch-Noels, A., Guenther, E., Haswell, C. A., Hatzes, A. P., Hebrard, G., Hekker, S., Helled, R., Heng, K., Jenkins, J. M., Johansen, A., Khodachenko, M. L., Kislyakova, K. G., Kley, W., Kolb, U., Krivova, N., Kupka, F., Lammer, H., Lanza, A. F., Lebreton, Y., Magrin, D., Marcos-Arenal, P., Marrese, P. M., Marques, J. P., Martins, J., Mathis, S., Mathur, S., Messina, S., Miglio, A., Montalban, J., Montalto, M., Monteiro, M. J. P. F. G., Moradi, H., Moravveji, E., Mordasini, C., Morel, T., Mortier, A., Nascimbeni, V., Nelson, R. P., Nielsen, M. B., Noack, L., Norton, A. J., Ofir, A., Oshagh, M., Ouazzani, R. -M, Papics, P., Parro, V. C., Petit, P., Plez, B., Poretti, E., Quirrenbach, A., Ragazzoni, R., Raimondo, G., Rainer, M., Reese, D. R., Redmer, R., Reffert, S., Rojas-Ayala, B., Roxburgh, I. W., Salmon, S., Santerne, A., Schneider, J., Schou, J., Schuh, S., Schunker, H., Silva-Valio, A., Silvotti, R., Skillen, I., Snellen, I., Sohl, F., Sousa, S. G., Sozzetti, A., Stello, D., Strassmeier, K. G., Svanda, M., Szabo, Gy. M., Tkachenko, A., Valencia, D., Van Grootel, V., Vauclair, S. D., Ventura, P., Wagner, F. W., Walton, N. A., Weingrill, J., Werner, S. C., Wheatley, P. J., Zwintz, K., Rauer, H., Catala, C., Aerts, C., Appourchaux, T., Benz, W., Brandeker, Aexis, Christensen-Dalsgaard, J., Deleuil, M., Gizon, L., Goupil, M. -J, Guedel, M., Janot-Pacheco, E., Mas-Hesse, M., Pagano, I., Piotto, G., Pollacco, D., Santos, N. C., Smith, A., Suarez, J. -C, Szabo, R., Udry, S., Adibekyan, V., Alibert, Y., Almenara, J. -M, Maro-Seoane, P. A., Ammler-von Eiff, M., Asplund, M., Antonello, E., Barnes, S., Baudin, F., Belkacem, K., Bergemann, M., Bihain, G., Birch, A. C., Bonfils, X., Boisse, I., Bonomo, A. S., Borsa, F., Brandao, I. M., Brocato, E., Brun, S., Burleigh, M., Burston, R., Cabrera, J., Cassisi, S., Chaplin, W., Charpinet, S., Chiappini, C., Church, R. P., Csizmadia, Sz., Cunha, M., Damasso, M., Davies, M. B., Deeg, H. J., Diaz, R. F., Dreizler, S., Dreyer, C., Eggenberger, P., Ehrenreich, D., Eigmueller, P., Erikson, A., Farmer, R., Feltzing, S., de Oliveira Fialho, F., Figueira, P., Forveille, T., Fridlund, M., Garcia, R. A., Giommi, P., Giuffrida, G., Godolt, M., Gomes da Silva, J., Granzer, T., Grenfell, J. L., Grotsch-Noels, A., Guenther, E., Haswell, C. A., Hatzes, A. P., Hebrard, G., Hekker, S., Helled, R., Heng, K., Jenkins, J. M., Johansen, A., Khodachenko, M. L., Kislyakova, K. G., Kley, W., Kolb, U., Krivova, N., Kupka, F., Lammer, H., Lanza, A. F., Lebreton, Y., Magrin, D., Marcos-Arenal, P., Marrese, P. M., Marques, J. P., Martins, J., Mathis, S., Mathur, S., Messina, S., Miglio, A., Montalban, J., Montalto, M., Monteiro, M. J. P. F. G., Moradi, H., Moravveji, E., Mordasini, C., Morel, T., Mortier, A., Nascimbeni, V., Nelson, R. P., Nielsen, M. B., Noack, L., Norton, A. J., Ofir, A., Oshagh, M., Ouazzani, R. -M, Papics, P., Parro, V. C., Petit, P., Plez, B., Poretti, E., Quirrenbach, A., Ragazzoni, R., Raimondo, G., Rainer, M., Reese, D. R., Redmer, R., Reffert, S., Rojas-Ayala, B., Roxburgh, I. W., Salmon, S., Santerne, A., Schneider, J., Schou, J., Schuh, S., Schunker, H., Silva-Valio, A., Silvotti, R., Skillen, I., Snellen, I., Sohl, F., Sousa, S. G., Sozzetti, A., Stello, D., Strassmeier, K. G., Svanda, M., Szabo, Gy. M., Tkachenko, A., Valencia, D., Van Grootel, V., Vauclair, S. D., Ventura, P., Wagner, F. W., Walton, N. A., Weingrill, J., Werner, S. C., Wheatley, P. J., and Zwintz, K.

Abstract

PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s cadence) providing a wide field-of-view (2232 deg(2)) and a large photometric magnitude range (4-16 mag). It focuses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4-10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e. g.: - complete our knowledge of planet di, AuthorCount:160

Published
2014
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