Publications by Jean-Loup Baudino


Toward the analysis of JWST exoplanet spectra: Identifying troublesome model parameters

ArXiv (0)

J-L Baudino, P Molliere, O Venot, P Tremblin, B Bezard, P-O Lagage

Given the forthcoming launch of the James Webb Space Telescope (JWST) which will allow observ- ing exoplanet atmospheres with unprecedented signal-over-noise ratio, spectral coverage and spatial resolution, the uncertainties in the atmosphere modelling used to interpret the data need to be as- sessed. As the first step, we compare three independent 1D radiative-convective models: ATMO, Exo-REM and petitCODE. We identify differences in physical and chemical processes taken into ac- count thanks to a benchmark protocol we developed. We study the impact of these differences on the analysis of observable spectra. We show the importance of selecting carefully relevant molecular linelists to compute the atmospheric opacity. Indeed, differences between spectra calculated with Hitran and ExoMol exceed the expected uncertainties of future JWST observations. We also show the limitation in the precision of the models due to uncertainties on alkali and molecule lineshape, which induce spectral effects also larger than the expected JWST uncertainties. We compare two chemical models, Exo-REM and Venot Chemical Code, which do not lead to significant differences in the emission or transmission spectra. We discuss the observational consequences of using equilibrium or out-of- equilibrium chemistry and the major impact of phosphine, detectable with the JWST.Each of the models has benefited from the benchmarking activity and has been updated. The protocol developed in this paper and the online results can constitute a test case for other models.


Dynamical models to explain observations with SPHERE in planetary systems with double debris belts

ArXiv e-prints (2017)

C Lazzoni, S Desidera, F Marzari, A Boccaletti, M Langlois, D Mesa, R Gratton, Q Kral, N Pawellek, J Olofsson, M Bonnefoy, G Chauvin, AM Lagrange, A Vigan, E Sissa, J Antichi, H Avenhaus, A Baruffolo, JL Baudino, A Bazzon, JL Beuzit, B Biller, M Bonavita, W Brandner, P Bruno, E Buenzli, F Cantalloube, E Cascone, A Cheetham, RU Claudi, M Cudel, S Daemgen, V De Caprio, P Delorme, D Fantinel, G Farisato, M Feldt, R Galicher, C Ginski, J Girard, E Giro, M Janson, J Hagelberg, T Henning, S Incorvaia, M Kasper, T Kopytova, J Lannier, H LeCoroller, L Lessio, R Ligi, AL Maire, F Ménard, M Meyer, J Milli, D Mouillet, S Peretti, C Perrot, D Rouan, M Samland, B Salasnich, G Salter, T Schmidt, S Scuderi, E Sezestre, M Turatto, S Udry, F Wildi, A Zurlo


Discovery of a warm, dusty giant planet around HIP 65426

Astronomy & Astrophysics 605 (2017) L9-L9

G Chauvin, S Desidera, A-M Lagrange, A Vigan, R Gratton, M Langlois, M Bonnefoy, J-L Beuzit, M Feldt, D Mouillet, M Meyer, A Cheetham, B Biller, A Boccaletti, V D’Orazi, R Galicher, J Hagelberg, A-L Maire, D Mesa, J Olofsson, M Samland, TOB Schmidt, E Sissa, M Bonavita, B Charnay, M Cudel, S Daemgen, P Delorme, P Janin-Potiron, M Janson, M Keppler, H Le Coroller, R Ligi, GD Marleau, S Messina, P Mollière, C Mordasini, A Müller, S Peretti, C Perrot, L Rodet, D Rouan, A Zurlo, C Dominik, T Henning, F Menard, H-M Schmid, M Turatto, S Udry, F Vakili, L Abe, J Antichi, A Baruffolo, P Baudoz, J Baudrand, P Blanchard, A Bazzon, T Buey, M Carbillet, M Carle, J Charton, E Cascone, R Claudi, A Costille, A Deboulbe, V De Caprio, K Dohlen, D Fantinel, P Feautrier, T Fusco, P Gigan, E Giro, D Gisler, L Gluck, N Hubin, E Hugot, M Jaquet, M Kasper, F Madec, Y Magnard, P Martinez, D Maurel, D Le Mignant, O Möller-Nilsson, M Llored, T Moulin, A Origné, A Pavlov, D Perret, C Petit, J Pragt, P Puget, P Rabou, J Ramos, R Rigal, S Rochat, R Roelfsema, G Rousset, A Roux, B Salasnich, J-F Sauvage, A Sevin, C Soenke, E Stadler, M Suarez, L Weber, F Wildi, S Antoniucci, J-C Augereau, J-L Baudino, W Brandner, N Engler, J Girard, C Gry, Q Kral, T Kopytova, E Lagadec, J Milli, C Moutou, J Schlieder, J Szulágyi, C Thalmann, Z Wahhaj


Orbiting a binary: SPHERE characterisation of the HD 284149 system

ArXiv e-prints (2017)

M Bonavita, V D Orazi, D Mesa, C Fontanive, S Desidera, S Messina, S Daemgen, R Gratton, A Vigan, M Bonnefoy, A Zurlo, J Antichi, H Avenhaus, A Baruffolo, JL Baudino, JL Beuzit, A Boccaletti, P Bruno, T Buey, M Carbillet, E Cascone, G Chauvin, RU Claudi, V De Caprio, D Fantinel, G Farisato, M Feldt, R Galicher, E Giro, C Gry, J Hagelberg, S Incorvaia, M Janson, M Jaquet, AM Lagrange, M Langlois, J Lannier, H Le Coroller, L Lessio, R Ligi, AL Maire, F Menard, C Perrot, S Peretti, C Petit, J Ramos, A Roux, B Salasnich, G Salter, M Samland, S Scuderi, J Schlieder, M Surez, M Turatto, L Weber


First light of the VLT planet finder SPHERE: IV. Physical and chemical properties of the planets around HR8799

Astronomy and Astrophysics 587 (2016)

M Bonnefoy, A Zurlo, JL Baudino, P Lucas, D Mesa, AL Maire, A Vigan, R Galicher, D Homeier, F Marocco, R Gratton, G Chauvin, F Allard, S Desidera, M Kasper, C Moutou, AM Lagrange, J Antichi, A Baruffolo, J Baudrand, JL Beuzit, A Boccaletti, F Cantalloube, M Carbillet, J Charton, RU Claudi, A Costille, K Dohlen, C Dominik, D Fantinel, P Feautrier, M Feldt, T Fusco, P Gigan, JH Girard, L Gluck, C Gry, T Henning, M Janson, M Langlois, F Madec, Y Magnard, D Maurel, D Mawet, MR Meyer, J Milli, O Moeller-Nilsson, D Mouillet, A Pavlov, D Perret, P Pujet, SP Quanz, S Rochat, G Rousset, A Roux, B Salasnich, G Salter, JF Sauvage, HM Schmid, A Sevin, C Soenke, E Stadler, M Turatto, S Udry, F Vakili, Z Wahhaj, F Wildi

© 2016 ESO. The system of fourplanets discovered around the intermediate-mass star HR8799 offers a unique opportunity to test planet formation theories at large orbital radii and to probe the physics and chemistry at play in the atmospheres of self-luminous young (~30 Myr) planets. We recently obtained new photometry of the four planets and low-resolution (R ~ 30) spectra of HR8799 d and e with the SPHERE instrument (Paper III). Aims. In this paper (Paper IV), we aim to use these spectra and available photometry to determine how they compare to known objects, what the planet physical properties are, and how their atmospheres work. Methods. We compare the available spectra, photometry, and spectral energy distribution (SED) of the planets to field dwarfs and young companions. In addition, we use the extinction from corundum, silicate (enstatite and forsterite), or iron grains likely to form in the atmosphere of the planets to try to better understand empirically the peculiarity of their spectrophotometric properties. To conclude, we use three sets of atmospheric models (BT-SETTL14, Cloud-AE60, Exo-REM) to determi ne which ingredients are critically needed in the models to represent the SED of the objects, and to constrain their atmospheric parameters (T eff , log g, M/H). Results. We find that HR8799d and e properties are well reproduced by those of L6-L8 dusty dwarfs discovered in the field, among which some are candidate members of young nearby associations. No known object reproduces well the properties of planets b and c. Nevertheless, we find that the spectra and WISE photometry of peculiar and/or young early-T dwarfs reddened by submicron grains made of corundum, iron, enstatite, or forsterite successfully reproduce the SED of these planets. Our analysis confirms that only the Exo-REM models with thick clouds fit (within 2σ) the whole set of spectrophotometric datapoints available for HR8799 d and e for T eff = 1200 K, log g in the range 3.0-4.5, and M/H = +0.5. The models still fail to reproduce the SED of HR8799c and b. The determination of the metallicity, log g, and cloud thickness are degenerate. Conclusions. Our empirical analysis and atmospheric modelling show that an enhanced content in dust and decreased CIA of H 2 is certainly responsible for the deviation of the properties of the planet with respect to field dwarfs. The analysis suggests in addition that HR8799c and b have later spectral types than the two other planets, and therefore could both have lower masses.


First light of the VLT planet finder SPHERE: I. Detection and characterization of the substellar companion GJ 758 B

Astronomy and Astrophysics 587 (2016)

A Vigan, M Bonnefoy, C Ginski, H Beust, R Galicher, M Janson, JL Baudino, E Buenzli, J Hagelberg, V D'Orazi, S Desidera, AL Maire, R Gratton, JF Sauvage, G Chauvin, C Thalmann, L Malo, G Salter, A Zurlo, J Antichi, A Baruffolo, P Baudoz, P Blanchard, A Boccaletti, JL Beuzit, M Carle, R Claudi, A Costille, A Delboulbe, K Dohlen, C Dominik, M Feldt, T Fusco, L Gluck, J Girard, E Giro, C Gry, T Henning, N Hubin, E Hugot, M Jaquet, M Kasper, AM Lagrange, M Langlois, D Le Mignant, M Llored, F Madec, P Martinez, D Mawet, D Mesa, J Milli, D Mouillet, T Moulin, C Moutou, A Origne, A Pavlov, D Perret, C Petit, J Pragt, P Puget, P Rabou, S Rochat, R Roelfsema, B Salasnich, HM Schmid, A Sevin, R Siebenmorgen, A Smette, E Stadler

© 2016 ESO. GJ 758 B is a brown dwarf companion to a nearby (15.76%) solar-type, metal-rich (M/H = + 0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (~600 K) companion ever directly imaged around a neighboring star. We present new high-contrast data obtained during the commissioning of the SPHERE instrument at the Very Large Telescope (VLT). The data was obtained in Y-, J-, H-, and K s -bands with the dual-band imaging (DBI) mode of IRDIS, thus providing a broad coverage of the full near-infrared (near-IR) range at higher contrast and better spectral sampling than previously reported. In this new set of high-quality data, we report the re-detection of the companion, as well as the first detection of a new candidate closer-in to the star. We use the new eight photometric points for an extended comparison of GJ 758 B with empirical objects and four families of atmospheric models. From comparison to empirical object, we estimate a T8 spectral type, but none of the comparison objects can accurately represent the observed near-IR fluxes of GJ 758 B. From comparison to atmospheric models, we attribute a T eff = 600 ± 100 K, but we find that no atmospheric model can adequately fit all the fluxes of GJ 758 B. The lack of exploration of metal enrichment in model grids appears as a major limitation that prevents an accurate estimation of the companion physical parameters. The photometry of the new candidate companion is broadly consistent with L-type objects, but a second epoch with improved photometry is necessary to clarify its status. The new astrometry of GJ 758 B shows a significant proper motion since the last epoch. We use this result to improve the determination of the orbital characteristics using two fitting approaches: Least-Squares Monte Carlo and Markov chain Monte Carlo. We confirm the high-eccentricity of the orbit (peak at 0.5), and find a most likely semi-major axis of 46.05 AU. We also use our imaging data, as well as archival radial velocity data, to reject the possibility that this is a false positive effect created by an unseen, closer-in, companion. Finally, we analyze the sensitivity of our data to additional closer-in companions and reject the possibility of other massive brown dwarf companions down to 4-5 AU.


Interpreting the photometry and spectroscopy of directly imaged planets: A new atmospheric model applied to β Pictoris b and SPHERE observations

Astronomy and Astrophysics 582 (2015)

JL Baudino, B Bézard, A Boccaletti, M Bonnefoy, AM Lagrange, R Galicher

© ESO, 2015. Context. Since the end of 2013 a new generation of instruments optimized to image young giant planets around nearby stars directly is becoming available on 8-m class telescopes, both at Very Large Telescope and Gemini in the southern hemisphere. Beyond the achievement of high contrast and the discovery capability, these instruments are designed to obtain photometric and spectral information to characterize the atmospheres of these planets. Aims. We aim to interpret future photometric and spectral measurements from these instruments, in terms of physical parameters of the planets, with an atmospheric model using a minimal number of assumptions and parameters. Methods. We developed the Exoplanet Radiative-convective Equilibrium Model (Exo-REM) to analyze the photometric and spectroscopic data of directly imaged planets. The input parameters are a planet's surface gravity (g), effective temperature (T eff ), and elemental composition. The model predicts the equilibrium temperature profile and mixing ratio profiles of the most important gases. Opacity sources include the H 2 -He collision-induced absorption and molecular lines from eight compounds (including CH 4 updated with the Exomol line list). Absorption by iron and silicate cloud particles is added above the expected condensation levels with a fixed scale height and a given optical depth at some reference wavelength. Scattering was not included at this stage. Results. We applied Exo-REM to photometric and spectral observations of the planet β Pictoris b obtained in a series of near-infrared filters. We derived T eff = 1550 ± 150 K, log (g) = 3.5 ± 1, and radius R = 1.76 ± 0.24 R Jup (2σ error bars from photometric measurements). These values are comparable to those found in the literature, although with more conservative error bars, consistent with the model accuracy. We were able to reproduce, within error bars, the J- and H-band spectra of β Pictoris b. We finally investigated the precision to which the above parameters can be constrained from SPHERE measurements using different sets of near-infrared filters as well as low-resolution spectroscopy.


Physical and orbital properties of β Pictoris b

Astronomy and Astrophysics 567 (2014)

M Bonnefoy, GD Marleau, R Galicher, H Beust, AM Lagrange, JL Baudino, G Chauvin, S Borgniet, N Meunier, J Rameau, A Boccaletti, A Cumming, C Helling, D Homeier, F Allard, P Delorme

The intermediate-mass star β Pictoris is known to be surrounded by a structured edge-on debris disk within which a gas giant planet was discovered orbiting at 8-10 AU. The physical properties of β Pic b were previously inferred from broad-and narrow-band 0.9-4.8 μm photometry. We used commissioning data of the Gemini Planet Imager (GPI) to obtain new astrometry and a lowresolution (R ∼ 35-39) J-band (1.12-1.35 μm) spectrum of the planet. We find that the planet has passed the quadrature. We constrain its semi-major axis to ≤10 AU (90% prob.) with a peak at 8.9 +0.4 -0.6 AU. The joint fit of the planet astrometry and the most recent radial velocity measurements of the star yields a planet dynamical mass lower than 20 M Jup (≥96% prob.). The extracted spectrum of β Pic b is similar to those of young L1 +1 -1.5 dwarfs. We used the spectral type estimate to revise the planet luminosity to log(L=L⊙) =-3.90±0.07. The 0.9-4.8 μm photometry and spectrum are reproduced for T eff = 1650 ± 150 K and a log g ≤ 4.7 dex by 12 grids of PHOENIX-based and LESIA atmospheric models. For the most recent system age estimate (21 ± 4 Myr), the bolometric luminosity and the constraints on the dynamical mass of β Pic b are only reproduced by warm-and hot-start tracks with initial entropies S i 10.5 k B /baryon. These initial conditions may result from an inefficient accretion shock and/or a planetesimal density at formation higher than in the classical core-accretion model. Considering a younger age for the system or a conservative formation time for β Pic b does not change these conclusions. © 2014 ESO.


Near-infrared detection and characterization of the exoplanet HD 95086 b with the Gemini Planet Imager

Astronomy and Astrophysics 565 (2014)

R Galicher, J Rameau, M Bonnefoy, JL Baudino, T Currie, A Boccaletti, G Chauvin, AM Lagrange, C Marois

HD 95086 is an intermediate-mass debris-disk-bearing star. VLT/NaCo 3.8 μm observations revealed it hosts a 5 ± 2 M Jup companion (HD 95086 b) at ≠56 AU. Follow-up observations at 1.66 and 2.18 μm yielded a null detection, suggesting extremely red colors for the planet and the need for deeper direct-imaging data. In this Letter, we report H-(1.7 μm) and K 1 -(2.05 μm) band detections of HD 95086 b from Gemini Planet Imager (GPI) commissioning observations taken by the GPI team. The planet position in both spectral channels is consistent with the NaCo measurements and we confirm it to be comoving. Our photometry yields colors of H-L′ = 3.6 ± 1.0 mag and K 1 -L′ = 2.4 ± 0.7 mag, consistent with previously reported 5-σ upper limits in H and Ks. The photometry of HD 95086 b best matches that of 2M 1207 b and HR 8799 cde. Comparing its spectral energy distribution with the BT-SETTL and LESIA planet atmospheric models yields T eff ~ 600-1500 K and log g ~ 2.1-4.5. Hot-start evolutionary models yield M = 5 ± 2 M Jup . Warm-start models reproduce the combined absolute fluxes of the object for M = 4-14 M Jup for a wide range of plausible initial conditions (S init = 8-13 k B /baryon). The color-magnitude diagram location of HD 95086 b and its estimated T eff and log g suggest that the planet is a peculiar L-T transition object with an enhanced amount of photospheric dust. © 2014 ESO.


A radiative-convective equilibrium model for young giant exoplanets: Application to β Pictoris b

Proceedings of the International Astronomical Union 8 (2013) 277-278

JL Baudino, B Bézard, A Boccaletti, M Bonnefoy, AM Lagrange

We present a radiative-convective equilibrium model for young giant exoplanets. Model predictions are compared with the existing photometric measurements of the planet β Pictoris b in the J, H, Ks, L', NB 4.05, M' bands. This model will be used to interpret future photometric and spectroscopic observations of exoplanets with SPHERE, mounted at the VLT with a first light expected mid-2014. Copyright © 2013, International Astronomical Union.