Examinando por Autor "Bourrier, V."

Mostrando 1 - 15 de 15

Acceso Abierto
A precise architecture characterization of the π Mensae planetary system
(EDP Sciences, 2020-10-01) Damasso, D.; Sozzetti, A; Lovis, C.; Barros, S. C. C.; Sousa, S. G.; Demangeon, O. D. S.; Faria, J. P.; Lillo Box, J.; Cristiani, S.; Pepe, F.; Rebolo, R.; Santos, N. C.; Zapatero Osorio, M. R.; Amate, M.; Pasquini, L.; Zerbi, Filippo M.; Adibekyan, V.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Álvarez, D.; Alves, D.; Ávila, G.; Baldini, V.; Bandy, T.; Benz, W.; Bianco, A.; Borsa, F.; Bossini, D.; Bourrier, V.; Bouchy, F.; Broeg, C.; Cabral, A.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; D´Odorico, V.; Deiries, S.; Dekker, H.; Delabre, B.; Di Marcoantonio, P.; Dumusque, X.; Ehrenreich, D.; Figueira, P.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lizon, J. L.; Lo Curto, G.; Maire, C.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Modigliani, A.; Molaro, P.; Monteiro, M. A.; Monteiro, M. J. P. F. G.; Moschetti, M.; Mueller, E.; Murphy, M. T.; Nunes, N.; Oggioni, L.; Oliveira, A.; Oshagh, M.; Pallé, E.; Pariani, G.; Poretti, E.; Rasilla, J. L.; Rebordao, J.; Redaelli, E.; Riva, M.; Santa Tschudi, S.; Santin, P.; Santos, P.; Ségransan, D.; Schmidt, T. M.; Segovia, A.; Sosnowska, D.; Spanò, P.; Suárez Mascareño, A.; Tabernero, H.; Tenegi, F.; Udry, S.; Zanutta, A.; González Hernández, Carmen; Swiss National Science Foundation (SNSF); Agenzia Spaziale Italiana (ASI); Fundação para a Ciência e a Tecnologia (FCT); Australian Research Council (ARC); Istituto Nazionale Astrofisica (INAF); 0000-0003-0987-1593; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The bright star pi Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the European Southern Observatory's Very Large Telescope. The star hosts a multi-planet system (a transiting 4 M-circle plus planet at similar to 0.07 au and a sub-stellar companion on a similar to 2100-day eccentric orbit), which is particularly suitable for a precise multi-technique characterization. Aims. With the new ESPRESSO observations, which cover a time span of 200 days, we aim to improve the precision and accuracy of the planet parameters and search for additional low-mass companions. We also take advantage of the new photometric transits of pi Men c observed by TESS over a time span that overlaps with that of the ESPRESSO follow-up campaign. Methods. We analysed the enlarged spectroscopic and photometric datasets and compared the results to those in the literature. We further characterized the system by means of absolute astrometry with HIPPARCOS and Gaia. We used the high-resolution spectra of ESPRESSO for an independent determination of the stellar fundamental parameters. Results. We present a precise characterization of the planetary system around pi Men. The ESPRESSO radial velocities alone (37 nightly binned data with typical uncertainty of 10 cm s(-1)) allow for a precise retrieval of the Doppler signal induced by pi Men c. The residuals show a root mean square of 1.2 m s(-1), which is half that of the HARPS data; based on the residuals, we put limits on the presence of additional low-mass planets (e.g. we can exclude companions with a minimum mass less than similar to 2 M-circle plus within the orbit of pi Men c). We improve the ephemeris of pi Men c using 18 additional TESS transits, and, in combination with the astrometric measurements, we determine the inclination of the orbital plane of pi Men b with high precision (i(b) =45.8(-1.1)(+1.4) deg). This leads to precise measurement of its absolute mass m(b) = =14.1(-0.4)(+0.5) M-Jup, indicating that pi Men b can be classified as a brown dwarf. Conclusions. The pi Men system represents a nice example of the extreme precision radial velocities that can be obtained with ESPRESSO for bright targets. Our determination of the 3D architecture of the pi Men planetary system and the high relative misalignment of the planetary orbital planes put constraints on and challenge the theories of the formation and dynamical evolution of planetary systems. The accurate measurement of the mass of pi Men b contributes to make the brown dwarf desert a bit greener.
Acceso Abierto
Atmospheric Rossiter–McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO
(EDP Sciences, 2021-01-22) Borsa, F.; Allart, R.; Casasayas Barris, N.; Tabernero, H. M.; Zapatero Osorio, M. R.; Cristiani, S.; Pepe, F.; Rebolo, R.; Santos, N. C.; Adibekyan, V.; Bourrier, V.; Demangeon, O. D. S.; Ehrenreich, D.; Pallé, E.; Sousa, S. G.; Lillo Box, J.; Lovis, C.; Micela, G.; Oshagh, M.; Poretti, E.; Sozzetti, A.; Allende Prieto, C.; Alibert, Y.; Amate, M.; Benz, W.; Bouchy, F.; Cabral, A.; Dekker, H.; D´Odorico, V.; Di Marcoantonio, P.; Figueira, P.; Genova Santos, R.; Lo Curto, G.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Molaro, P.; Nunes, N. J.; Riva, M.; Suárez Mascareño, A.; Udry, S.; Zerbi, Filippo M.; González Hernández, Carmen; Istituto Nazionale di Astrofisica (INAF); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Cabral, A. [0000-0002-9433-871X]; Adibekyan, V. [0000-0002-0601-6199]; Santos, N. [0000-0003-4422-2919]; Nunes, N. [0000-0002-3837-6914]; Sozzetti, A. [0000-0002-7504-365X]; Suarez Mascareño, A. [0000-0002-3814-5323]
Context. Ultra-hot Jupiters are excellent laboratories for the study of exoplanetary atmospheres. WASP-121b is one of the most studied; many recent analyses of its atmosphere report interesting features at different wavelength ranges. Aims. In this paper we analyze one transit of WASP-121b acquired with the high-resolution spectrograph ESPRESSO at VLT in one-telescope mode, and one partial transit taken during the commissioning of the instrument in four-telescope mode. Methods. We take advantage of the very high S/N data and of the extreme stability of the spectrograph to investigate the anomalous in-transit radial velocity curve and study the transmission spectrum of the planet. We pay particular attention to the removal of instrumental effects, and stellar and telluric contamination. The transmission spectrum is investigated through single-line absorption and cross-correlation with theoretical model templates. Results. By analyzing the in-transit radial velocities we were able to infer the presence of the atmospheric Rossiter–McLaughlin effect. We measured the height of the planetary atmospheric layer that correlates with the stellar mask (mainly Fe) to be 1.052 ± 0.015 Rp and we also confirmed the blueshift of the planetary atmosphere. By examining the planetary absorption signal on the stellar cross-correlation functions we confirmed the presence of a temporal variation of its blueshift during transit, which could be investigated spectrum-by-spectrum thanks to the quality of our ESPRESSO data. We detected significant absorption in the transmission spectrum for Na, H, K, Li, Ca II, and Mg, and we certified their planetary nature by using the 2D tomographic technique. Particularly remarkable is the detection of Li, with a line contrast of ~0.2% detected at the 6σ level. With the cross-correlation technique we confirmed the presence of Fe I, Fe II, Cr I, and V I. Hα and Ca II are present up to very high altitudes in the atmosphere (~1.44 Rp and ~2 Rp, respectively), and also extend beyond the transit-equivalent Roche lobe radius of the planet. These layers of the atmosphere have a large line broadening that is not compatible with being caused by the tidally locked rotation of the planet alone, and could arise from vertical winds or high-altitude jets in the evaporating atmosphere.
Acceso Abierto
Broadband transmission spectroscopy of HD 209458b with ESPRESSO: evidence for Na, TiO, or both
(EDP Sciences, 2020-12-01) Santos, N. C.; Cristo, E.; Demangeon, O. D. S.; Oshagh, M.; Allart, R.; Barros, S. C. C.; Borsa, F.; Bourrier, V.; Casasayas Barris, N.; Ehrenreich, D.; Faria, J. P.; Figueira, P.; Martins, J. H. C.; Micela, G.; Pallé, E.; Sozzetti, A.; Tabernero, H.; Zapatero Osorio, M. R.; Pepe, F.; Cristiani, S.; Rebolo, R.; Adibekyan, V.; Allende Prieto, C.; Alibert, Y.; Bouchy, F.; Cabral, A.; Dekker, H.; Di Marcoantonio, P.; D´Odorico, V.; Dumusque, X.; Lavie, B.; Lo Curto, G.; Lovis, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Molaro, P.; Nunes, N. J.; Poretti, E.; Rivas, M.; Sousa, S. G.; Suárez Mascareño, A.; Udry, S.; González Hernández, Carmen; Fundacao para a Ciencia e a Tecnologia (FCT); Istituto Nazionale di Astrofisica (INAF); European Research Council (ERC); Agencia Estatal de Investigación (AEI); 0000-0003-4422-2919; 0000-0001-5992-7589; 0000-0001-7918-0355; 0000-0002-0715-8789; 0000-0003-0987-1593
Context. The detection and characterization of exoplanet atmospheres is currently one of the main drivers pushing the development of new observing facilities. In this context, high-resolution spectrographs are proving their potential and showing that high-resolution spectroscopy will be paramount in this field. Aims. We aim to make use of ESPRESSO high-resolution spectra, which cover two transits of HD 209458b, to probe the broadband transmission optical spectrum of the planet. Methods. We applied the chromatic Rossiter–McLaughin method to derive the transmission spectrum of HD 209458b. We compared the results with previous HST observations and with synthetic spectra. Results. We recover a transmission spectrum of HD 209458b similar to the one obtained with HST data. The models suggest that the observed signal can be explained by only Na, only TiO, or both Na and TiO, even though none is fully capable of explaining our observed transmission spectrum. Extra absorbers may be needed to explain the full dataset, though modeling approximations and observational errors can also be responsible for the observed mismatch. Conclusions. Using the chromatic Rossiter–McLaughlin technique, ESPRESSO is able to provide broadband transmission spectra of exoplanets from the ground, in conjunction with space-based facilities, opening good perspectives for similar studies of other planets.
Acceso Abierto
ESPRESSO at VLT On-sky performance and first results
(EDP Sciences, 2021-01-19) Pepe, F.; Cristiani, S.; Rebolo, R.; Santos, N. C.; Dekker, H.; Cabral, A.; Di Marcoantonio, P.; Figueira, P.; Lo Curto, G.; Lovis, C.; Mayor, M.; Mégevand, D.; Molaro, P.; Riva, M.; Zapatero Osorio, M. R.; Amate, M.; Manescau, A.; Pasquini, L.; Zerbi, Filippo M.; Adibekyan, V.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Álvarez, D.; Alves, D.; Ávila, G.; Baldini, V.; Bandy, T.; Barros, S. C. C.; Benz, W.; Bianco, A.; Borsa, F.; Bourrier, V.; Bouchy, F.; Broeg, C.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; D´Odorico, V.; Damasso, M.; Deiries, S.; Delabre, B.; Demangeon, O. D. S.; Dumusque, X.; Ehrenreich, D.; Faria, J. P.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lillo Box, J.; Lizon, J. L.; Maire, C.; Martins, C. J. A. P.; Mehner, A.; Micela, G.; Modigliani, A.; Monteiro, M. A.; Monteiro, M. J. P. F. G.; Moschetti, M.; Murphy, M. T.; Nunes, N.; Oggioni, L.; Oliveira, A.; Oshagh, M.; Pallé, E.; Pariani, G.; Poretti, E.; Rasilla, J. L.; Rebordao, J.; Redaelli, E.; Santana Tschudi, S.; Santin, P.; Santos, P.; Ségransan, D.; Schmidt, T. M.; Segovia, A.; Sosnowska, D.; Sozzetti, A.; Sousa, S. G.; Spanò, P.; Suárez Mascareño, A.; Tabernero, H.; Tenegi, F.; Udry, S.; Zanutta, A.; González Hernández, Carmen; Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Australian Research Council; 0000-0002-9433-871X; 0000-0003-0513-8116; 0000-0002-4339-0550; 0000-0002-6728-244X; 0000-0003-2434-3625; 0000-0002-7504-365X; 0000-0002-7040-5498; 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. ESPRESSO is the new high-resolution spectrograph of ESO’s Very Large Telescope (VLT). It was designed for ultra-high radial-velocity (RV) precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. It is able to observe with any of the four Unit Telescopes (UTs) of the VLT at a spectral resolving power of 140 000 or 190 000 over the 378.2 to 788.7 nm wavelength range; it can also observe with all four UTs together, turning the VLT into a 16 m diameter equivalent telescope in terms of collecting area while still providing a resolving power of 70 000. Aims. We provide a general description of the ESPRESSO instrument, report on its on-sky performance, and present our Guaranteed Time Observation (GTO) program along with its first results. Methods. ESPRESSO was installed on the Paranal Observatory in fall 2017. Commissioning (on-sky testing) was conducted between December 2017 and September 2018. The instrument saw its official start of operations on October 1, 2018, but improvements to the instrument and recommissioning runs were conducted until July 2019. Results. The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65″ exceeds the 10% mark under nominal astroclimatic conditions. We demonstrate an RV precision of better than 25 cm s−1 during a single night and 50 cm s−1 over several months. These values being limited by photon noise and stellar jitter shows that the performance is compatible with an instrumental precision of 10 cm s−1. No difference has been measured across the UTs, neither in throughput nor RV precision. Conclusions. The combination of the large collecting telescope area with the efficiency and the exquisite spectral fidelity of ESPRESSO opens a new parameter space in RV measurements, the study of planetary atmospheres, fundamental constants, stellar characterization, and many other fields.
Acceso Abierto
ESPRESSO high-resolution transmission spectroscopy of WASP-76 b
(EDP Sciences, 2021-02-19) Tabernero, H. M.; Zapatero Osorio, M. R.; Allart, R.; Borsa, F.; Casasayas Barris, N.; Demangeon, O. D. S.; Ehrenreich, D.; Lillo Box, J.; Lovis, C.; Pallé, E.; Sousa, S. G.; Rebolo, R.; Santos, N. C.; Pepe, F.; Cristiani, S.; Adibekyan, V.; Allende Prieto, C.; Alibert, Y.; Barros, S. C. C.; Bouchy, F.; Bourrier, V.; D´Odorico, V.; Dumusque, X.; Faria, J. P.; Figueira, P.; Genova Santos, R.; Hojjatpanah, S.; Lo Curto, G.; Lavie, B.; Martins, C. J. A. P.; Martins, J. H. C.; Mehner, A.; Micela, G.; Molaro, P.; Nunes, N. J.; Poretti, E.; Seidel, J. V.; Sozzetti, A.; Suárez Mascareño, A.; Udry, S.; Aliverti, M.; Affolter, M.; Alves, D.; Amate, M.; Ávila, G.; Bandy, T.; Benz, W.; Bianco, A.; Broeg, C.; Cabral, A.; Conconi, P.; Coelho, J.; Cumani, C.; Deiries, S.; Dekker, H.; Delabre, B.; Fragoso, A.; Genoni, M.; Genolet, L.; Hughes, I.; Knudstrup, J.; Kerber, F.; Landoni, M.; Lizon, J. L.; Maire, C.; Manescau, A.; Di Marcoantonio, P.; Mégevand, D.; Monteiro, M.; Moschetti, M.; Mueller, E.; Modigliani, A.; Oggioni, L.; Oliveira, A.; Pariani, G.; Pasquini, L.; Rasilla, J. L.; Redaelli, E.; Riva, M.; Santana Tschudi, S.; Santin, P.; Santos, P.; Segovia, A.; Sosnowska, D.; Spanò, P.; Tenegi, F.; Iwert, O.; Zanutta, A.; Zerbi, Filippo M.; González Hernández, Carmen; European Research Council (ERC); Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Istituto Nazionale di Astrofisica (INAF); Cabral, A. [0000-0002-9433-871X]; Monteiro, M. J. [0000-0003-0513-8116]; Coelho, F. M. [0000-0002-4339-0550]; Faria, J. [0000-0002-6728-244X]; Santos, N. [0000-0003-4422-2919]
Aims. We report on ESPRESSO high-resolution transmission spectroscopic observations of two primary transits of the highly irradiated, ultra-hot Jupiter-sized planet, WASP-76b. We investigated the presence of several key atomic and molecular features of interest that may reveal the atmospheric properties of the planet. Methods. We extracted two transmission spectra of WASP-76b with R ≈ 140 000 using a procedure that allowed us to process the full ESPRESSO wavelength range (3800–7880 Å) simultaneously. We observed that at a high signal-to-noise ratio, the continuum of ESPRESSO spectra shows ‘wiggles’, which are likely caused by an interference pattern outside the spectrograph. To search for the planetary features, we visually analysed the extracted transmission spectra and cross-correlated the observations against theoretical spectra of different atomic and molecular species. Results. The following atomic features are detected: Li I, Na I, Mg I, Ca II, Mn I, K I, and Fe I. All are detected with a confidence level between 9.2 σ (Na I) and 2.8 σ (Mg I). We did not detect the following species: Ti I, Cr I, Ni I, TiO, VO, and ZrO. We impose the following 1 σ upper limits on their detectability: 60, 77, 122, 6, 8, and 8 ppm, respectively. Conclusions. We report the detection of Li I on WASP-76b for the first time. In addition, we confirm the presence of Na I and Fe I as previously reported in the literature. We show that the procedure employed in this work can detect features down to the level of ~0.1% in the transmission spectrum and ~10 ppm by means of a cross-correlation method. We discuss the presence of neutral and singly ionised features in the atmosphere of WASP-76b.
Acceso Abierto
HST PanCET program: non-detection of atmospheric escape in the warm Saturn-sized planet WASP-29 b
(EDP Sciences, 2021-05-07) Dos Santos, L. A.; Bourrier, V.; Ehrenreich, D.; Sanz Forcada, J.; López Morales, M.; Sing, D. K.; García Muñoz, Antonio; Henry, G. W.; Lavvas, P.; Lecavelier des Etangs, A.; Mikal Evans, T.; Vidal Madjar, A.; Wakeford, H. R.; Centre National D'Etudes Spatiales (CNES); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Dos Santos, L. A. [0000-0002-2248-3838]; Sanz Forcada, J. [0000-0002-1600-7835]; López Morales, M. [0000-0003-3204-8183]; Sing, D. K. [0000-0001-6050-7645]; García Muñoz, A. [0000-0003-1756-4825]; Henry, G. W. [0000-0003-4155-8513]; Lecavelier des Etangs, A. [0000-0002-5637-5253]; Mikal Evans, T. [0000-0001-5442-1300]
Short-period gas giant exoplanets are susceptible to intense atmospheric escape due to their large scale heights and strong high-energy irradiation. This process is thought to occur ubiquitously, but to date we have only detected direct evidence of atmospheric escape in hot Jupiters and warm Neptunes. The latter planets are particularly more sensitive to escape-driven evolution as a result of their lower gravities with respect to Jupiter-sized planets. But the paucity of cases for intermediate, Saturn-sized exoplanets at varying levels of irradiation precludes a detailed understanding of the underlying physics in atmospheric escape of hot gas giants. Aiming to address this issue, our objectives here are to assess the high-energy environment of the warm (Teq = 970 K) Saturn WASP-29 b and search for signatures of atmospheric escape. We used far-ultraviolet observations from the Hubble Space Telescope to analyze the flux time series of H I, C II, Si III, Si IV, and N V during the transit of WASP-29 b. At 88 pc, a large portion of the Lyman-α core of the K4V-type host WASP-29 is attenuated by interstellar medium absorption, limiting our ability to probe the escape of H at velocities between −84 and +35 km s−1. At 3σ confidence, we rule out any in-transit absorption of H I larger than 92% in the Lyman-α blue wing and 19% in the red wing. We found an in-transit flux decrease of 39%−11%+12% in the ground-state C II emission line at 1334.5 Å. But due to this signal being significantly present in only one visit, it is difficult to attribute a planetary or stellar origin to the ground-state C II signal. We place 3σ absorption upper limits of 40, 49, and 24% on Si III, Si IV, and for excited-state C II at 1335.7 Å, respectively. Low activity levels and the faint X-ray luminosity suggest that WASP-29 is an old, inactive star. Nonetheless, an energy-limited approximation combined with the reconstructed EUV spectrum of the host suggests that the planet is losing its atmosphere at a relatively large rate of 4 × 109 g s−1. The non-detection at Lyman-α could be partly explained by a low fraction of escaping neutral hydrogen, or by the state of fast radiative blow-out we infer from the reconstructed Lyman-α line.
Restringido
Nightside condensation of iron in an ultrahot giant exoplanet
(Nature Research Journals, 2020-03-11) Ehrenreich, D.; Lovis, C.; Allart, R.; Zapatero Osorio, M. R.; Pepe, F.; Cristiani, S.; Rebolo, R.; Santos, N. C.; Borsa, F.; Demangeon, O. D. S.; Dumusque, X.; Casasayas Barris, N.; Séngrasan, D.; Sousa, S.; Abreu, M.; Adibekyan, V.; Affolter, M.; Allende Prieto, C.; Alibert, Y.; Aliverti, M.; Alves, D.; Amate, M.; Ávila, G.; Baldini, V.; Bandy, T.; Benz, W.; Bianco, A.; Bolmont, É.; Bouchy, F.; Bourrier, V.; Broeg, C.; Cabral, A.; Calderone, G.; Pallé, E.; Cegla, H. M.; Cirami, R.; Coelho, João M. P.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; Dekker, H.; Delabre, B.; Deiries, S.; D´Odorico, V.; Di Marcoantonio, P.; Figueira, P.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Harada, N.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lizon, J. L.; Lendl, M.; Lo Curto, G.; Maire, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Modigliani, A.; Molaro, P.; Monteiro, M.; Monteiro, M. A.; Moschetti, M.; Muller, N.; Nunes, N.; Oggioni, L.; Oliveira, A.; Pariani, G.; Pasquini, L.; Poretti, E.; Rasilla, J. L.; Redaelli, E.; Riva, M.; Santana Tschudi, S.; Santin, P.; Santos, P.; Segovia Milla, A.; Seidel, J. V.; Sosnowska, D.; Sozzetti, A.; Spanò, P.; Suárez Mascareño, A.; Tabernero, H.; Tenegi, F.; Udry, S.; Zanutta, A.; Zerbi, Filippo M.; González Hernández, Carmen; European Research Council (ERC); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Suárez Mascareño, A. [0000-0002-3814-5323]; Abreu, M. [0000-0002-0716-9568]; João M. P. Coelho. [0000-0002-4339-0550]; Monteiro, M. J. [0000-0003-0513-8116]; Tabernero, H. [0000-0002-8087-4298]; Nunes, N. J. [0000-0002-3837-6914]; Cabral, A. [0000-0002-9433-871X]; Molaro, P. [0000-0002-0571-4163]; Redaelli, E. M. A. [0000-0001-8185-2122]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Castro Alves, D. [0000-0001-7026-2514]; Seidel, J. V. [0000-0002-7990-9596]; Martins, C. J. A. P. [0000-0002-4886-9261]; Adibekyan, V. [0000-0002-0601-6199]; Zerbi, F. M. [0000-0002-9996-973X]; Monteiro, M. [0000-0001-5644-0898]; Mehner, A. [0000-0002-9564-3302]; Santos, N. [0000-0003-4422-2919]; Cegla, H. [0000-0001-8934-7315]; Sozzetti, A. [0000-0002-7504-365X]; Allart, R. [0000-0002-1199-9759]; Landoni, M. [0000-0001-5570-5081]; Coretti, I. [0000-0001-9374-3249]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Ultrahot giant exoplanets receive thousands of times Earth’s insolation1,2. Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates and chemistry3,4,5. Daysides are predicted to be cloud-free, dominated by atomic species6 and much hotter than nightsides5,7,8. Atoms are expected to recombine into molecules over the nightside9, resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed10,11,12,13,14, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night (‘evening’) and night-to-day (‘morning’) terminators could, however, be revealed as an asymmetric absorption signature during transit4,7,15. Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by −11 ± 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside16. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.
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 atmosphere of HD 209458b seen with ESPRESSO No detectable planetary absorptions at high resolution
(EDP Sciences, 2021-03-02) Casasayas Barris, N.; Pallé, E.; Strangret, M.; Bourrier, V.; Tabernero, H. M.; Yan, F.; Borsa, F.; Allart, R.; Zapatero Osorio, M. R.; Lovis, C.; Sousa, S. G.; Chen, G.; Oshagh, M.; Santos, N. C.; Pepe, F.; Rebolo, R.; Molaro, P.; Cristiani, S.; Adibekyan, V.; Alibert, Y.; Allende Prieto, C.; Bouchy, F.; Demangeon, O. D. S.; Di Marcoantonio, P.; D´Odorico, V.; Ehrenreich, D.; Figueira, P.; Génova Santos, R.; Lavie, B.; Lillo Box, J.; Lo Curto, G.; Martins, C. J. A. P.; Mehner, A.; Micela, G.; Nunes, N. J.; Poretti, E.; Sozzetti, A.; Suárez Mascareño, A.; Udry, S.; González Hernández, Carmen; National Natural Science Foundation of China (NSFC); Deutsche Forschungsgemeinschaft (DFG); European Research Council (ERC); Fundacao para a Ciencia e a Tecnologia (FCT); Istituto Nazionale di Astrofisica (INAF); Agencia Estatal de Investigación (AEI); Swiss National Science Foundation (SNSF); Yan, F. [0000-0001-9585-9034]; Sozzetti, A. [0000-0002-7504-365X]; Nunes, N. [0000-0002-3837-6914]; 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 observed two transits of the iconic gas giant HD 209458b between 380 and 780 nm, using the high-resolution ESPRESSO spectrograph. The derived planetary transmission spectrum exhibits features at all wavelengths where the parent star shows strong absorption lines, for example, Na I, Mg I, Fe I, Fe II, Ca I, V I, Hα, and K I. We interpreted these features as the signature of the deformation of the stellar line profiles due to the Rossiter-McLaughlin effect, combined with the centre-to-limb effects on the stellar surface, which is in agreement with similar reports recently presented in the literature. We also searched for species that might be present in the planetary atmosphere but not in the stellar spectra, such as TiO and VO, and obtained a negative result. Thus, we find no evidence of any planetary absorption, including previously reported Na I, in the atmosphere of HD 209458b. The high signal-to-noise ratio in the transmission spectrum (~1700 at 590 nm) allows us to compare the modelled deformation of the stellar lines in assuming different one-dimensional stellar atmospheric models. We conclude that the differences among various models and observations remain within the precision limits of the data. However, the transmission light curves are better explained when the centre-to-limb variation is not included in the computation and only the Rossiter-McLaughlin deformation is considered. This demonstrates that ESPRESSO is currently the best facility for spatially resolving the stellar surface spectrum in the optical range using transit observations and carrying out empirical validations of stellar models.
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 Hubble PanCET program: long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470
(EDP Sciences, 2021-06-08) Bourrier, V.; Dos Santos, L. A.; Sanz Forcada, J.; García Muñoz, Antonio; Henry, G. W.; Lavvas, P.; Lecavelier, A.; López Morales, M.; Mikal Evans, T.; Sing, D. K.; Wakeford, H. R.; Ehrenreich, D.; European Research Council (ERC)
Neptune-size exoplanets seem particularly sensitive to atmospheric evaporation, making it essential to characterize the stellar high-energy radiation that drives this mechanism. This is particularly important with M dwarfs, which emit a large and variable fraction of their luminosity in the ultraviolet and can display strong flaring behavior. The warm Neptune GJ 3470b, hosted by an M2 dwarf, was found to harbor a giant exosphere of neutral hydrogen thanks to three transits observed with the Hubble Space Telescope Imaging Spectrograph (HST/STIS). Here we report on three additional transit observations from the Panchromatic Comparative Exoplanet Treasury program, obtained with the HST Cosmic Origin Spectrograph. These data confirm the absorption signature from GJ 3470b’s exosphere in the stellar Lyman-α line and demonstrate its stability over time. No planetary signatures are detected in other stellar lines, setting a 3σ limit on GJ 3470b’s far-ultraviolet (FUV) radius at 1.3 times its Roche lobe radius. We detect three flares from GJ 3470. They show different spectral energy distributions but peak consistently in the Si III line, which traces intermediate-temperature layers in the transition region. These layers appear to play a particular role in GJ 3470’s activity as emission lines that form at lower or higher temperatures than Si III evolved differently over the long term. Based on the measured emission lines, we derive synthetic X-ray and extreme-ultraviolet (X+EUV, or XUV) spectra for the six observed quiescent phases, covering one year, as well as for the three flaring episodes. Our results suggest that most of GJ 3470’s quiescent high-energy emission comes from the EUV domain, with flares amplifying the FUV emission more strongly. The neutral hydrogen photoionization lifetimes and mass loss derived for GJ 3470b show little variation over the epochs, in agreement with the stability of the exosphere. Simulations informed by our XUV spectra are required to understand the atmospheric structure and evolution of GJ 3470b and the role played by evaporation in the formation of the hot-Neptune desert.
Acceso Abierto
The Hubble Space Telescope PanCET Program: An Optical to Infrared Transmission Spectrum of HAT-P-32Ab
(The Institute of Physics (IOP), 2020-07-02) Alam, M. K.; López Morales, M.; Nikolov, N.; Sing, D. K.; Henry, G. W.; Baxter, C.; Désert, J. M.; Barstow, J. K.; Mikal Evans, T.; Bourrier, V.; Lavvas, P.; Wakeford, H. R.; Williamson, M. H.; Sanz Forcada, J.; Buchhave, L. A.; Cohen, O.; García Muñoz, Antonio; Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); European Research Council (ERC); Alam, M. K. [0000-0003-4157-832X]; López Morales, M. [0000-0003-3204-8183]; Nikolov, N. [0000-0002-6500-3574]; Sing, D. K. [0000-0001-6050-7645]; Henry, G. W. [0000-0003-4155-8513]; Baxter, C. [0000-0003-3438-843X]; Désert, J. M. [0000-0002-0875-8401]; Barstow, J. K. [0000-0003-3726-5419]; Mikal Evans, T. [0000-0001-5442-1300]; Bourrier, V. [0000-0002-9148-034X]; Lavvas, P. [0000-0002-5360-3660]; Wakeford, H. R. [0000-0003-4328-3867]; Forcada, J. S. [0000-0002-1600-7835]; Buchhave, L. A. [0000-0003-1605-5666]; Cohen, O. [0000-0003-3721-0215]; García Muñoz, A. [0000-0003-1756-4825]
We present a 0.3−5 μm transmission spectrum of the hot Jupiter HAT-P-32Ab observed with the Space Telescope Imaging Spectrograph and Wide Field Camera 3 instruments mounted on the Hubble Space Telescope, combined with Spitzer Infrared Array Camera photometry. The spectrum is composed of 51 spectrophotometric bins with widths ranging between 150 and 400 Å, measured to a median precision of 215 ppm. Comparisons of the observed transmission spectrum to a grid of 1D radiative-convective equilibrium models indicate the presence of clouds/hazes, consistent with previous transit observations and secondary eclipse measurements. To provide more robust constraints on the planet's atmospheric properties, we perform the first full optical to infrared retrieval analysis for this planet. The retrieved spectrum is consistent with a limb temperature of ${1248}_{-92}^{+92}$ K, a thick cloud deck, enhanced Rayleigh scattering, and ~10× solar H2O abundance. We find log(Z/Z⊙) = ${2.41}_{-0.07}^{+0.06}$, and compare this measurement with the mass–metallicity relation derived for the solar system.
Acceso Abierto
WASP-127b: a misaligned planet with a partly cloudy atmosphere and tenuous sodium signature seen by ESPRESSO
(EDP Sciences, 2020-12-16) Allart, R.; Pino, L.; Lovis, C.; Sousa, S. G.; Casasayas Barris, N.; Zapatero Osorio, M. R.; Cretignier, M.; Pallé, E.; Pepe, F.; Cristiani, S.; Rebolo, R.; Santos, N. C.; Borsa, F.; Bourrier, V.; Demangeon, O. D. S.; Ehrenreich, D.; Lavie, B.; Lendl, M.; Lillo Box, J.; Micela, G.; Oshagh, M.; Sozzetti, A.; Tabernero, H.; Adibekyan, V.; Allende Prieto, C.; Alibert, Y.; Amate, M.; Benz, W.; Bouchy, F.; Cabral, A.; Dekker, H.; D´Odorico, V.; Di Marcantonio, P.; Dumusque, X.; Figueira, P.; Genova Santos, R.; Lo Curto, G.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Molaro, P.; Nunes, N. J.; Poretti, E.; Riva, M.; Suárez Mascareño, A.; Udry, S.; Zerbi, Filippo M.; González Hernández, Carmen; Swiss National Science Foundation (SNSF); European Research Council (ERC); Fundacao para a Ciencia e a Tecnologia (FCT); Istituto Nazionale di Astrofisica (INAF)
Context. The study of exoplanet atmospheres is essential for understanding the formation, evolution, and composition of exoplanets. The transmission spectroscopy technique is playing a significant role in this domain. In particular, the combination of state-of-the-art spectrographs at low- and high-spectral resolution is key to our understanding of atmospheric structure and composition. Aims. We observed two transits of the close-in sub-Saturn-mass planet, WASP-127b, with ESPRESSO in the frame of the Guaranteed Time Observations Consortium. We aim to use these transit observations to study the system architecture and the exoplanet atmosphere simultaneously. Methods. We used the Reloaded Rossiter-McLaughlin technique to measure the projected obliquity lambda and the projected rotational velocity nu(eq).sin(i(*)). We extracted the high-resolution transmission spectrum of the planet to study atomic lines. We also proposed a new cross-correlation framework to search for molecular species and we applied it to water vapor. Results. The planet is orbiting its slowly rotating host star (nu(eq).sin(i(*)) = 0.53(-0.05)(+0.07) km s(-1)) on a retrograde misaligned orbit (lambda = -128.41(+5.60)degrees(-5.46)). We detected the sodium line core at the 9-sigma confidence level with an excess absorption of 0.34 +/- 0.04%, a blueshift of 2.74 +/- 0.79 km s(-1), and a full width at half maximum of 15.18 +/- 1.75 km s(-1). However, we did not detect the presence of other atomic species but set upper limits of only a few scale heights. Finally, we put a 3-sigma upper limit on the average depth of the 1600 strongest water lines at equilibrium temperature in the visible band of 38 ppm. This constrains the cloud-deck pressure between 0.3 and 0.5 mbar by combining our data with low-resolution data in the near-infrared and models computed for this planet. Conclusions. WASP-127b, with an age of about 10 Gyr, is an unexpected exoplanet by its orbital architecture but also by the small extension of its sodium atmosphere (similar to 7 scale heights). ESPRESSO allows us to take a step forward in the detection of weak signals, thus bringing strong constraints on the presence of clouds in exoplanet atmospheres. The framework proposed in this work can be applied to search for molecular species and study cloud-decks in other exoplanets.
Acceso Abierto
WASP-52b. The effect of star-spot correction on atmospheric retrievals
(Oxford Academics: Oxford University Press, 2019-11-18) Bruno, G.; Lewis, N. K.; Alam, M. K.; López Morales, M.; Barstow, J. K.; Wakeford, H. R.; Sing, D. K.; Henry, G. W.; Ballester, G. E.; Bourrier, V.; Buchhave, L. A.; Cohen, O.; Mikal Evans, T.; García Muñoz, Antonio; Lavvas, P.; Sanz Forcada, J.; Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); European Research Council (ERC); Deutsche Forschungsgemeinschaft (DFG); Buchhave, L. A. [0000-0003-1605-5666]; Bruno, G. [0000-0002-3288-0802]; Sing, D. [0000-0001-6050-7645]; Mikal Evans, T. [0000-0001-5442-1300]; Alam, M. [0000-0003-4157-832X]; Wakeford, H. [0000-0003-4328-3867]
We perform atmospheric retrievals on the full optical to infrared (⁠0.3−5μm⁠) transmission spectrum of the inflated hot Jupiter WASP-52b by combining HST/STIS, WFC3 IR, and Spitzer/IRAC observations. As WASP-52 is an active star that shows both out-of-transit photometric variability and star-spot crossings during transits, we account for the contribution of non-occulted active regions in the retrieval. We recover a 0.1–10× solar atmospheric composition, in agreement with core accretion predictions for giant planets, and no significant contribution of aerosols. We also obtain a <3000 K temperature for the star-spots, a measure which is likely affected by the models used to fit instrumental effects in the transits, and a 5 per cent star-spot fractional coverage, compatible with expectations for the host star’s spectral type. Such constraints on the planetary atmosphere and on the activity of its host star will inform future JWST GTO observations of this target.