Revisiting the atmosphere of the exoplanet 51 Eridani b with VLT/SPHERE

Abstract

[Full abstract in the paper] We aim to better constrain the atmospheric properties of the directly imaged exoplanet 51~Eri~b by using a retrieval approach on higher signal-to-noise data than previously reported. In this context, we also compare the results of using the atmospheric retrieval code \texttt{petitRADTRANS} vs a self-consistent model to fit atmospheric parameters. We present a higher signal-to-noise $YH$ spectrum of the planet and revised $K1K2$ photometry (M${}_{K1}=15.11\pm 0.04$ mag, M${}_{K2}=17.11\pm 0.38$ mag). The best-fit parameters obtained using an atmospheric retrieval differ from previous results using self-consistent models. In general, we find that our solutions tend towards cloud-free atmospheres (e.g. log ${\tau }_{\mathrm{clouds}}=-5.20\pm 1.44$). For our ``nominal'' model with new data, we find a lower metallicity ([Fe/H] $=0.26\pm$0.30 dex) and C/O ratio ($0.38\pm 0.09$), and a slightly higher effective temperature (T${}_{\mathrm{eff}}=807\pm$45 K) than previous studies. The surface gravity (log $g=4.05\pm 0.37$) is in agreement with the reported values in the literature within uncertainties. We estimate the mass of the planet to be between 2 and 4 M${}_{\mathrm{Jup}}$. When comparing with self-consistent models, we encounter a known correlation between the presence of clouds and the shape of the $P-T$ profiles. Our findings support the idea that results from atmospheric retrievals should not be discussed in isolation, but rather along with self-consistent temperature structures obtained using the retrieval's best-fit parameters.

Accepted for publication in A&A. 21 pages, 7 figures in the main text and 9 figures in the Appendix

References in corpus (35)

• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• petitRADTRANS: a Python radiative transfer package for exoplanet characterization and retrieval
• Fundamental limitations of high contrast imaging set by small sample statistics
• Fingering convection and cloudless models for cool brown dwarf atmospheres
• The SPHERE infrared survey for exoplanets (SHINE). III. The demographics of young giant exoplanets below 300 au with SPHERE
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e
• Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs I: Characterizing Benchmarks, Gl570D and HD3651B
• A novel L-band imaging search for giant planets in the Tucana and Beta Pictoris moving groups
• Characterizing 51 Eri b from 1-5 $\mu$m: a partly-cloudy exoplanet
• Spitzer/MIPS Observations of Stars in the Beta Pictoris Moving Group
• Retrieval of Exoplanet Emission Spectra with HyDRA
• Cloud busting: enstatite and quartz clouds in the atmosphere of 2M2224-0158
• Direct detection of exoplanets in the 3 -- 10 micron range with E-ELT/METIS
• Gas and dust in the Beta Pictoris Moving Group as seen by the Herschel Space Observatory
• A Sensitive Identification of Warm Debris Disks in the Solar Neighborhood Through Precise Calibration of Saturated WISE Photometry
• A Uniform Retrieval Analysis of Ultracool Dwarfs. III. Properties of Y-Dwarfs
• Unveiling cloudy exoplanets: the influence of cloud model choices on retrieval solutions
• The SPHERE infrared survey for exoplanets (SHINE) -- II. Observations, Data reduction and analysis Detection performances and early-results
• Thermo-compositional diabatic convection in the atmospheres of brown dwarfs and in Earth's atmosphere and oceans
• Stellar atmospheric parameters for 754 spectra from the X-shooter Spectral Library
• The SPHERE infrared survey for exoplanets (SHINE)- I Sample definition and target characterization
• The Young Suns Exoplanet Survey: Detection of a wide orbit planetary mass companion to a solar-type Sco-Cen member
• Cloudless atmospheres for young low-gravity substellar objects
• The 12CO/13CO isotopologue ratio of a young, isolated brown dwarf. Possibly distinct formation pathways of super-Jupiters and brown dwarfs
• Planets Around Low-Mass Stars (PALMS). VI. Discovery of a Remarkably Red Planetary-Mass Companion to the AB Dor Moving Group Candidate 2MASS J22362452+4751425
• Hint of curvature in the orbital motion of the exoplanet 51 Eridani b using 3 years of VLT/SPHERE monitoring
• Synthetic Evolution Tracks of Giant Planets
• TRAP: A temporal systematics model for improved direct detection of exoplanets at small angular separations
• The B-Star Exoplanet Abundance Study: a co-moving 16-25 Mjup companion to the young binary system HIP 79098
• Limits on the Mass and Initial Entropy of 51 Eri b from Gaia EDR3 Astrometry
• GRAVITY K-band spectroscopy of HD 206893 B: brown dwarf or exoplanet
• Directly imaged exoplanets in reflected starlight. The importance of knowing the planet radius
• An updated visual orbit of the directly-imaged exoplanet 51 Eridani b and prospects for a dynamical mass measurement with Gaia
• Low-mass members of nearby young stellar moving groups from Gaia EDR3

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