Examinando por Autor "Benz, W."

Mostrando 1 - 9 de 9

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
Characterization of the K2-38 planetary system Unraveling one of the densest planets known to date
(EDP Sciences, 2020-09-14) Toledo Padrón, B.; Lovis, C.; Suárez Mascareño, A.; Barros, S. C. C.; Sozzetti, A.; Bouchy, F.; Zapatero Osorio, M. R.; Rebolo, R.; Cristiani, S.; Pepe, F. A.; Santos, N. C.; Sousa, S. G.; Tabernero, H. M.; Lillo Box, J.; Bossini, D.; Adibekyan, V.; Allart, R.; Damasso, M.; D´Odorico, V.; Figueira, P.; Lavie, B.; Lo Curto, G.; Mehner, A.; Micela, G.; Modigliani, A.; Nunes, N. J.; Pallé, E.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allende Prieto, C.; Alves, D.; Amate, M.; Ávila, G.; Baldini, V.; Bandy, T.; Benatti, S.; Benz, W.; Bianco, A.; Broeg, C.; Cabral, A.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; Deiries, S.; Dekker, H.; Delabre, B.; Demangeon, O. D.; Di Marcoantonio, P.; Ehrenreich, D.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Knudstrup, J.; Landoni, M.; Lizon, J. L.; Maire, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Molaro, P.; Monteiro, M. J. P. F. G.; Monteiro, M. A.; Moschetti, M.; Mueller, E.; Oggioni, L.; Oliveira, A.; Rivas, M.; Santana Tschudi, S.; Santin, P.; Santos, P.; Segovia, A.; Sosnowska, D.; Spanò, P.; Tenegi, F.; Udry, S.; Zanutta, A.; Zerbi, Filippo M.; González Hernández, Carmen; Fundacion La Caixa; Swiss National Science Foundation (SNSF); European Research Council (ERC); Fundacao para a Ciencia e a Tecnologia (FCT); Ministerio de Ciencia e Innovación (MICINN); 0000-0001-8160-5076; 0000-0003-0987-1593; 0000-0001-5664-2852; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. An accurate characterization of the known exoplanet population is key to understanding the origin and evolution of planetary systems. Determining true planetary masses through the radial velocity (RV) method is expected to experience a great improvement thanks to the availability of ultra-stable echelle spectrographs. Aims. We took advantage of the extreme precision of the new-generation echelle spectrograph ESPRESSO to characterize the transiting planetary system orbiting the G2V star K2-38 located at 194 pc from the Sun with V similar to 11.4. This system is particularly interesting because it could contain the densest planet detected to date. Methods. We carried out a photometric analysis of the available K2 photometric light curve of this star to measure the radius of its two known planets, K2-38b and K2-38c, with P-b = 4.01593 +/- 0.00050 d and P-c = 10.56103 +/- 0.00090 d, respectively. Using 43 ESPRESSO high-precision RV measurements taken over the course of 8 months along with the 14 previously published HIRES RV measurements, we modeled the orbits of the two planets through a Markov chain Monte Carlo analysis, significantly improving their mass measurements. Results. Using ESPRESSO spectra, we derived the stellar parameters, T-eff = 5731 +/- 66, log g = 4.38 +/- 0.11 dex, and [Fe/H] = 0 :26 +/- 0.05 dex, and thus the mass and radius of K2-38, M-star = 1.03(-0.02)(+0.04) M-circle plus and R-circle plus = 1.06+0:09 0:06 R-circle plus. We determine new values for the planetary properties of both planets. We characterize K2-38b as a super-Earth with R-P = 1.54 +/- 0.14 R-circle plus and M-p = 7.3(-1.0)(+1:1) M-circle plus, and K2-38c as a sub-Neptune with RP = 2.29 +/- 0.26 R-circle plus and M-p = 8.3(-1.3)(+1:3) M (circle plus). Combining the radius and mass measurements, we derived a mean density of rho(p) = 11.0(-2.8)(+4:1) g cm(-3) for K2-38b and rho(p) = 3.8+1:8 1:1 g cm(-3) for K2-38c, confirming K2-38b as one of the densest planets known to date. Conclusions. The best description for the composition of K2-38b comes from an iron-rich Mercury-like model, while K2-38c is better described by a rocky-model with H2 envelope. The maximum collision stripping boundary shows how giant impacts could be the cause for the high density of K2-38b. The irradiation received by each planet places them on opposite sides of the radius valley. We find evidence of a long-period signal in the RV time-series whose origin could be linked to a 0.25-3 MJ planet or stellar activity.
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.
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
Revisiting Proxima with ESPRESSO
(EDP Sciences, 2020-07-13) Suárez Mascareño, A.; Faria, J. P.; Figueira, P.; Lovis, C.; Damasso, M.; Rebolo, R.; Cristiani, S.; Pepe, F.; Santos, N. C.; Zapatero Osorio, M. R.; Adibekyan, V.; Hojjatpanah, S.; Sozzetti, A.; Murgas Alcaino, F.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Alves, D.; Amate, M.; Ávila, G.; Baldini, V.; Bandi, T.; Barros, S. C. C.; Bianco, A.; Benz, W.; 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.; Delabre, B.; Di Marcantonio, P.; Dumusque, X.; Ehrenreich, D.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Kerber, F.; Knusdstrup, J.; Landoni, M.; Lavie, B.; Lillo Box, J.; Lizon, J.; Lo Curto, G.; Maire, C.; Manescau, A.; 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.; Nunes, N. J.; Oggioni, L.; Oliveira, A.; Pallé, E.; Pariani, G.; Pasquini, L.; Poretti, E.; Rasilla, J. L.; Redaelli, E.; Riva, M.; Santana Tschudi, S.; Santin, P.; Santos, P.; Segovia, A.; Sosnowska, D.; Sousa, S.; Spanò, P.; Tenegi, F.; Udry, S.; Zanutta, A.; Zerbi, Filippo M.; González Hernández, Carmen; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Lillo Box, J. [0000-0003-3742-1987]; Faria, J. [0000-0002-6728-244X]; Nunes, N. J. [0000-0002-3837-6914]; Molaro, P. [0000-0002-0571-4163]; Mascareño, A. S. [0000-0002-3814-5323]; Cabral, A. [0000-0002-9433-871X]; Monteiro, M. J. P. F. G. [0000-0003-0513-8116]; Redaelli, E. M. A. [0000-0001-8185-2122]; Barros, S. [0000-0003-2434-3625]; Santos, N. [0000-0003-4422-2919]; Abreu, M. [0000-0002-0716-9568]; Coretti, I. [0000-0001-9374-3249]; Sozzetti, A. [0000-0002-7504-365X]; Adibekyan, V. [0000-0002-0601-6199]; Monteiro, M. [0000-0001-5644-0898]; Damasso, M. [0000-0001-9984-4278]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The discovery of Proxima b marked one of the most important milestones in exoplanetary science in recent years. Yet the limited precision of the available radial velocity data and the difficulty in modelling the stellar activity calls for a confirmation of the Earth-mass planet. Aims. We aim to confirm the presence of Proxima b using independent measurements obtained with the new ESPRESSO spectrograph, and refine the planetary parameters taking advantage of its improved precision. Methods. We analysed 63 spectroscopic ESPRESSO observations of Proxima (Gl 551) taken during 2019. We obtained radial velocity measurements with a typical radial velocity photon noise of 26 cm s−1. We combined these data with archival spectroscopic observations and newly obtained photometric measurements to model the stellar activity signals and disentangle them from planetary signals in the radial velocity (RV) data. We ran a joint Markov chain Monte Carlo analysis on the time series of the RV and full width half maximum of the cross-correlation function to model the planetary and stellar signals present in the data, applying Gaussian process regression to deal with the stellar activity signals. Results. We confirm the presence of Proxima b independently in the ESPRESSO data and in the combined ESPRESSO+ HARPS+UVES dataset. The ESPRESSO data on its own shows Proxima b at a period of 11.218 ± 0.029 days, with a minimum mass of 1.29 ± 0.13 M⊕. In the combined dataset we measure a period of 11.18427 ± 0.00070 days with a minimum mass of 1.173 ± 0.086 M⊕. We get a clear measurement of the stellar rotation period (87 ± 12 d) and its induced RV signal, but no evidence of stellar activity as a potential cause for the 11.2 days signal. We find some evidence for the presence of a second short-period signal, at 5.15 days with a semi-amplitude of only 40 cm s−1. If caused by a planetary companion, it would correspond to a minimum mass of 0.29 ± 0.08 M⊕. We find that forthe case of Proxima, the full width half maximum of the cross-correlation function can be used as a proxy for the brightness changes and that its gradient with time can be used to successfully detrend the RV data from part of the influence of stellar activity. The activity-induced RV signal in the ESPRESSO data shows a trend in amplitude towards redder wavelengths. Velocities measured using the red end of the spectrograph are less affected by activity, suggesting that the stellar activity is spot dominated. This could be used to create differential RVs that are activity dominated and can be used to disentangle activity-induced and planetary-induced signals. The data collected excludes the presence of extra companions with masses above 0.6 M⊕ at periods shorter than 50 days.
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
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.