A medium-resolution spectrum of the exoplanet HIP 65426 b

Abstract

Medium-resolution integral-field spectrographs (IFS) coupled with adaptive-optics such as Keck/OSIRIS, VLT/MUSE, or SINFONI are appearing as a new avenue for enhancing the detection and characterization capabilities of young, gas giant exoplanets at large heliocentric distances (>5 au). We analyzed K-band VLT/SINFONI medium-resolution (R_lambda~5577) observations of the young giant exoplanet HIP 65426 b. Our dedicated IFS data analysis toolkit (TExTRIS) optimized the cube building, star registration, and allowed for the extraction of the planet spectrum. A Bayesian inference with the nested sampling algorithm coupled with the self-consistent forward atmospheric models BT-SETTL15 and Exo-REM using the ForMoSA tool yields Teff=1560 +/- 100K, log(g)<4.40dex, [M/H]=0.05 +/- 0.22dex, and an upper limit on the C/O ratio (<0.55). The object is also re-detected with the so-called "molecular mapping" technique. The technique yields consistent atmospheric parameters, but the loss of the planet pseudo-continuum in the process degrades or modifies the constraints on these parameters. The solar to sub-solar C/O ratio suggests an enrichment by solids at formation if the planet was formed beyond the water snowline (>20 au) by core-accretion. However, a formation by gravitational instability can not be ruled out. The metallicity is compatible with the bulk enrichment of massive Jovian planets from the Bern planet population models. Finally, we measure a radial velocity of 26 +/- 15km/s compatible with our revised measurement on the star. This is the fourth imaged exoplanet for which a radial velocity can be evaluated, illustrating the potential of such observations for assessing the coevolution of imaged systems belonging to star forming regions, such as HIP 65426.

21 pages, 16 figures, 3 Appendix

References in corpus (45)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Bayes in the sky: Bayesian inference and model selection in cosmology
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• petitRADTRANS: a Python radiative transfer package for exoplanet characterization and retrieval
• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• The fast spin-rotation of a young extrasolar planet
• Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere
• The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters
• A method to remove residual OH emission from near infrared spectra
• Imaging the water-snow line during a protostellar outburst
• Direct Imaging and Spectroscopy of a Planetary Mass Candidate Companion to a Young Solar Analog
• A comparison of chemistry and dust cloud formation in ultracool dwarf model atmospheres
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e
• VIP: Vortex Image Processing package for high-contrast direct imaging
• Discovery of a warm, dusty giant planet around HIP65426
• Simultaneous Detection of Water, Methane and Carbon Monoxide in the Atmosphere of Exoplanet HR8799b
• The Planetary Mass Companion 2MASS1207-3932 B: Temperature, Mass and Evidence for an Edge-On Disk
• A Systematic Study of Departures from Chemical Equilibrium in the Atmospheres of Substellar Mass Objects
• Protoplanetary disk rings and gaps across ages and luminosities
• Peering into the formation history of beta Pictoris b with VLTI/GRAVITY long baseline interferometry
• Characterizing 51 Eri b from 1-5 $\mu$m: a partly-cloudy exoplanet
• Excess C/O and C/H in outer protoplanetary disk gas
• Disk evolution, element abundances and cloud properties of young gas giant planets
• Direct evidence of a sub-stellar companion around CT Cha
• Very high contrast IFU spectroscopy of AB Doradus C: 9 mag contrast at 0.2" without a coronagraph using spectral deconvolution
• Evidence for a circumplanetary disk around protoplanet PDS 70 b
• Radial Velocity Measurements of HR 8799 b and c with Medium Resolution Spectroscopy
• In-depth study of moderately young but extremely red, very dusty substellar companion HD206893B
• Midplane temperature and outer edge of the protoplanetary disk around HD 163296
• On the Composition of Young, Directly Imaged Giant Planets
• The optical+infrared L dwarf spectral sequence of young planetary-mass objects in the Upper Scorpius association
• First High-Contrast Science with an Integral Field Spectrograph: the Sub-Stellar Companion to GQ Lup
• Spectral and orbital characterisation of the directly imaged giant planet HIP 65426 b
• Near-IR integral-field spectroscopy of the companion to GQ Lup
• Exploring the formation by core accretion and the luminosity evolution of directly imaged planets: The case of HIP 65426 b
• The Young Substellar Companion ROXs 12 B: Near-Infrared Spectrum, System Architecture, and Spin-Orbit Misalignment
• A new take on the low-mass brown dwarf companions on wide-orbits in Upper-Scorpius
• Exploring the RCrA environment with SPHERE: Discovery of a new stellar companion
• Characterising brown dwarf companions with IRDIS long-slit spectroscopy: HD 1160 B and HD 19467 B
• First spectroscopic observations of the sub-stellar companion of the young debris disk star PZ Telescopii
• High signal-to-noise spectral characterization of the planetary-mass object HD 106906 b
• L-band Spectroscopy with Magellan-AO/Clio2: First Results on Young Low-Mass Companions
• Integral field spectroscopy of L 449-1 -- A test case for spectral differential imaging with SINFONI
• Atmospheric Characterization and Further Orbital Modeling of $\kappa$ And b

Cited by in corpus (32)

• Assessing the C/O Ratio Formation Diagnostic: A Potential Trend with Companion Mass
• Four-of-a-kind? Comprehensive atmospheric characterisation of the HR 8799 planets with VLTI/GRAVITY
• JWST MIRI/MRS in-flight absolute flux calibration and tailored fringe correction for unresolved sources
• The JWST Early Release Science Program for the Direct Imaging & Spectroscopy of Exoplanetary Systems
• Peering into the Young Planetary System AB Pic. Atmosphere, Orbit, Obliquity & Second Planetary Candidate
• The Enhanced Resolution Imager and Spectrograph for the VLT
• X-SHYNE: X-shooter spectra of young exoplanet analogs. I. A medium-resolution 0.65-2.5$\mu \mathrm{m}$ one-shot spectrum of VHS\,1256-1257 b
• Molecular mapping of the PDS70 system: No molecular absorption signatures from the forming planet PDS70 b
• Emission line variability of young 10-30 Mjup companions : I. The case of GQ Lup b and GSC 06214-00210 b
• Behind the Mask: can HARMONI@ELT detect biosignatures in the reflected light of Proxima b?
• Atmospheric properties of AF Lep b with forward modeling
• Simulated performance of the molecular mapping for young giant exoplanets with the Medium Resolution Spectrometer of JWST/MIRI
• Moderate-Resolution $K$-Band Spectroscopy of the Substellar Companion VHS 1256 b
• Rotation and Abundances of the Benchmark Brown Dwarf HD 33632 Ab from Keck/KPIC High-resolution Spectroscopy
• Direct imaging of exoplanets: Legacy and prospects
• In-depth direct imaging and spectroscopic characterization of the young Solar System analog HD 95086
• Trade-offs in high-contrast integral field spectroscopy for exoplanet detection and characterisation: Young gas giants in emission
• Machine Learning for Exoplanet Detection in High-Contrast Spectroscopy: Revealing Exoplanets by Leveraging Hidden Molecular Signatures in Cross-Correlated Spectra with Convolutional Neural Networks
• Multi-modal atmospheric characterization of $\beta$ Pictoris b: Adding high-resolution continuum spectra from GRAVITY
• Exoplanets detection limits using spectral cross-correlation with spectro-imaging. An analytical model applied to the case of ELT-HARMONI
• An imaged 15Mjup companion within a hierarchical quadruple system
• A kinematical study of the launching region of the blueshifted HH 46/47 outflow with SINFONI K-band observations
• CROCODILE \\ Incorporating medium-resolution spectroscopy of close-in directly imaged exoplanets into atmospheric retrievals via cross-correlation
• X-SHYNE: X-Shooter spectra of young exoplanet analogs II. Presentation and analysis of the full library
• High-contrast spectroscopy with the new VLT/ERIS instrument: Molecular maps and radial velocity of the gas giant AF Lep b
• The planetary-mass-limit VLT/SINFONI library: Spectral extraction and atmospheric characterization via forward modeling
• The mid-infrared spectrum of $\beta$ Pictoris b. First VLTI/MATISSE interferometric observations of an exoplanet
• A High-Resolution Spectroscopic Survey of Directly Imaged Companion Hosts: II. Diversity in C/O Ratios among Host Stars
• Combining high-contrast imaging with high-resolution spectroscopy: Actual on-sky MIRI/MRS results compared to expectations
• Stellar halo subtraction alternative for accreting companions' characterization with integral field spectroscopy: Analytical and on-sky demonstration on the PDS70, HTLup, and YSES1 systems
• JWST-TST High Contrast: First Direct Spectroscopy of GJ 504 b reveals Clouds and Possible Metal Enrichment
• Next-generation Exo-REM atmospheric models: application to VHS 1256 b to emulate patchy clouds