Deep exploration of the planets HR 8799 b, c, and d with moderate resolution spectroscopy

Abstract

The four directly imaged planets orbiting the star HR 8799 are an ideal laboratory to probe atmospheric physics and formation models. We present more than a decade's worth of Keck/OSIRIS observations of these planets, which represent the most detailed look at their atmospheres to-date by its resolution and signal to noise ratio. We present the first direct detection of HR 8799 d, the second-closest known planet to the star, at moderate spectral resolution with Keck/OSIRIS (K-band; R~4,000). Additionally, we uniformly analyze new and archival OSIRIS data (H and K band) of HR 8799 b, c, and d. First, we show detections of water (H2O) and carbon monoxide (CO) in the three planets and discuss the ambiguous case of methane (CH4) in the atmosphere of HR 8799b. Then, we report radial velocity (RV) measurements for each of the three planets. The RV measurement of HR 8799 d is consistent with predictions made assuming coplanarity and orbital stability of the HR 8799 planetary system. Finally, we perform a uniform atmospheric analysis on the OSIRIS data, published photometric points, and low resolution spectra. We do not infer any significant deviation from to the stellar value of the carbon to oxygen ratio (C/O) of the three planets, which therefore does not yet yield definitive information about the location or method of formation. However, constraining the C/O ratio for all the HR 8799 planets is a milestone for any multiplanet system, and particularly important for large, widely separated gas giants with uncertain formation processes.

arXiv commentAccepted to AJ

References in corpus (91)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• Gaia Data Release 2. Summary of the contents and survey properties
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The effects of snowlines on C/O in planetary atmospheres
• Images of a fourth planet orbiting HR 8799
• Models of Stars, Brown Dwarfs and Exoplanets
• A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• ExoMol line lists IV: The rotation-vibration spectrum of methane up to 1500 K
• 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
• Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b
• Bayesian analysis to identify new star candidates in nearby young stellar kinematic groups
• Pulkovo Compilation of Radial Velocities for 35495 Hipparcos Stars in a Common System
• Dynamic temperature selection for parallel-tempering in Markov chain Monte Carlo simulations
• The Runts of the Litter: Why planets formed through gravitational instability can only be failed binary stars
• A Combined Subaru/VLT/MMT 1--5 Micron Study of Planets Orbiting HR 8799: Implications for Atmospheric Properties, Masses, and Formation
• The Tucana/Horologium, Columba, AB Doradus, and Argus Associations: New Members and Dusty Debris Disks
• The Two Modes of Gas Giant Planet Formation
• Retrieving Temperatures and Abundances of Exoplanet Atmospheres with High-Resolution Cross-Correlation Spectroscopy
• The Debris Disk Around HR 8799
• Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b
• Chemical enrichment of giant planets and discs due to pebble drift
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e
• Near-Infrared Spectroscopy of the Extrasolar Planet HR 8799 b
• Techniques and Review of Absolute Flux Calibration from the Ultraviolet to the Mid-Infrared
• A global cloud map of the nearest known brown dwarf
• Tracing the formation history of giant planets in protoplanetary disks with Carbon, Oxygen, Nitrogen and Sulphur
• Simultaneous Detection of Water, Methane and Carbon Monoxide in the Atmosphere of Exoplanet HR8799b
• Population-Level Eccentricity Distributions of Imaged Exoplanets and Brown Dwarf Companions: Dynamical Evidence for Distinct Formation Channels
• First light of the VLT planet finder SPHERE. III. New spectrophotometry and astrometry of the HR8799 exoplanetary system
• Atmospheric Signatures of Giant Exoplanet Formation by Pebble Accretion
• Carbon monoxide and water vapor in the atmosphere of the non-transiting exoplanet HD 179949 b
• Model atmospheres for massive gas giants with thick clouds: Application to the HR 8799 planets and predictions for future detections
• Detection and Characterization of Exoplanets using Projections on Karhunen-Loeve Eigenimages: Forward Modeling
• orbitize!: A Comprehensive Orbit-fitting Software Package for the High-contrast Imaging Community
• Stability of the directly imaged multiplanet system HR 8799: resonance and masses
• First direct detection of an exoplanet by optical interferometry; Astrometry and K-band spectroscopy of HR8799 e
• HELIOS-Retrieval: An Open-source, Nested Sampling Atmospheric Retrieval Code, Application to the HR 8799 Exoplanets and Inferred Constraints for Planet Formation
• First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs
• Chemical Imaging of the CO Snow Line in the HD 163296 Disk
• First light of the VLT planet finder SPHERE. IV. Physical and chemical properties of the planets around HR8799
• Directly Imaged L-T Transition Exoplanets in the Mid-Infrared
• Peering into the formation history of beta Pictoris b with VLTI/GRAVITY long baseline interferometry
• Dynamical Constraints on the HR 8799 Planets with GPI
• The Young Planet-mass Object 2M1207b: a cool, cloudy, and methane-poor atmosphere
• Constructing A Flexible Likelihood Function For Spectroscopic Inference
• M-band Imaging of the HR 8799 Planetary System Using an Innovative LOCI-based Background Subtraction Technique
• Jupiter's composition suggests its core assembled exterior to the N2 snowline
• Atmospheric Retrieval Analysis of the Directly Imaged Exoplanet HR 8799b
• Reconnaissance of the HR 8799 Exosolar System II: Astrometry and Orbital Motion
• Resolved Imaging of the HR 8799 Debris Disk with Herschel
• Evidence Against an Edge-On Disk Around the Extrasolar Planet 2MASS 1207 b and a New Thick Cloud Explanation for its Under-Luminosity
• Doppler Imaging of Exoplanets and Brown Dwarfs
• Gemini Planet Imager Spectroscopy of the HR 8799 planets c and d
• The slow spin of the young sub-stellar companion GQ Lupi b and its orbital configuration
• Thermal Infrared MMTAO Observations of the HR 8799 Planetary System
• The CHARA Array Angular Diameter of HR 8799 Favors Planetary Masses for Its Imaged Companions
• Resolved Submillimeter Observations of the HR 8799 and HD 107146 Debris Disks
• Resolving the Planetesimal Belt of HR 8799 with ALMA
• Astrometric Monitoring of the HR 8799 Planets: Orbit Constraints from Self-Consistent Measurements
• VLT/SPHERE robust astrometry of the HR8799 planets at milliarcsecond-level accuracy Orbital architecture analysis with PyAstrOFit
• Radial Velocity Measurements of HR 8799 b and c with Medium Resolution Spectroscopy
• A possible architecture of the planetary system HR 8799
• Deep Thermal Infrared Imaging of HR 8799 bcde: New Atmospheric Constraints and Limits on a Fifth Planet
• GPI spectra of HR 8799 c, d, and e from 1.5 to 2.4$\mu$m with KLIP Forward Modeling
• Obliquity Constraints on an Extrasolar Planetary-Mass Companion
• Jupiter formed as a pebble pile around the N${}_2$ ice line
• Composition of Early Planetary Atmospheres II: Coupled Dust and Chemical Evolution in Protoplanetary Disks
• GPI PSF subtraction with TLOCI: the next evolution in exoplanet/disk high-contrast imaging
• Disentangling Time Series Spectra with Gaussian Processes: Applications to Radial Velocity Analysis
• Precise Radial Velocities of Cool Low Mass Stars With iSHELL
• COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-Gravity T4 Benchmark around an Old White Dwarf and A Re-Examination of the Surface-Gravity Dependence of the L/T Transition
• The Scattered Disc of HR 8799
• On the Chemical Abundance of HR 8799 and the Planet c
• Detecting Exomoons Via Doppler Monitoring of Directly Imaged Exoplanets
• An exact, generalised Laplace resonance in the HR 8799 planetary system
• Resolved Millimeter Observations of the HR 8799 Debris Disk
• Improving Orbit Estimates for Incomplete Orbits with a New Approach to Priors -- with Applications from Black Holes to Planets
• Molecule mapping of HR8799b using OSIRIS on Keck: Strong detection of water and carbon monoxide, but no methane
• Detecting Water In the atmosphere of HR 8799 c with L-band High Dispersion Spectroscopy Aided By Adaptive Optics
• Efficiency Measurements and Installation of a New Grating for the OSIRIS Spectrograph at Keck Observatory
• Moderate-Resolution $K$-Band Spectroscopy of Substellar Companion $\kappa$ Andromedae b
• Characterizing and Improving the Data Reduction Pipeline for the Keck OSIRIS Integral Field Spectrograph
• The orbital architecture and debris disks of the HR 8799 planetary system
• Shaping HR8799's outer dust belt with an unseen planet
• Modelling the Inner Debris Disc of HR 8799
• Retrieval of Precise Radial Velocities from Near-Infrared High Resolution Spectra of Low Mass Stars

Cited by in corpus (38)

• A Clear View of a Cloudy Brown Dwarf Companion from High-Resolution Spectroscopy
• Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments are Common
• Detecting exomoons from radial velocity measurements of self-luminous planets: application to observations of HR 7672 B and future prospects
• 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
• Peering into the Young Planetary System AB Pic. Atmosphere, Orbit, Obliquity & Second Planetary Candidate
• Retrieving C and O Abundance of HR 8799 c by Combining High- and Low-Resolution Data
• Direct emission spectroscopy of exoplanets with the medium resolution imaging spectrometer on board JWST MIRI: I. Molecular mapping and sensitivity to instrumental effects
• The ESO SupJup Survey III: Confirmation of 13CO in YSES 1 b and Atmospheric Detection of YSES 1 c with CRIRES+
• Joint Constraints on Exoplanetary Orbits from Gaia DR3 and Doppler Data
• An Atmospheric Retrieval of the Brown Dwarf Gliese 229B
• Imaging detection of the inner dust belt and the four exoplanets in the HR8799 system with JWST's MIRI coronagraph
• Atmospheric Monitoring and Precise Spectroscopy of the HR 8799 Planets with SCExAO/CHARIS
• Dynamical Mass of the Exoplanet Host Star HR 8799
• The ESO SupJup Survey II: The 12C/13C ratios of three young brown dwarfs with CRIRES${}^{+}$
• Behind the Mask: can HARMONI@ELT detect biosignatures in the reflected light of Proxima b?
• Simulated performance of the molecular mapping for young giant exoplanets with the Medium Resolution Spectrometer of JWST/MIRI
• The ESO SupJup Survey IV. Unveiling the carbon isotope ratio of GQ Lup B and its host star
• 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
• Atmospheric characterization of the super-Jupiter HIP 99770 b with KPIC
• Detecting Exoplanets Closer to Stars with Moderate Spectral Resolution Integral-Field Spectroscopy
• Trade-offs in high-contrast integral field spectroscopy for exoplanet detection and characterisation: Young gas giants in emission
• Vortex Fiber Nulling for Exoplanet Observations: Implementation and First Light
• Jupiter-like uniform metal enrichment in a system of multiple giant exoplanets
• The compositions of the HR 8799 planets reflect accretion of both solids and metal-enriched gas
• Impacts of high-contrast image processing on atmospheric retrievals
• Inferring Late Stage Enrichment of Exoplanet Atmospheres from Observed Interstellar Comets
• A High-Resolution Spectroscopic Survey of Directly Imaged Companion Hosts: I. Determination of diagnostic stellar abundances for planet formation and composition
• Mapping the Skies of Ultracool Worlds: Detecting Storms and Spots with Extremely Large Telescopes
• Direct Spectroscopy of 51 Eridani b with JWST NIRSpec
• CROCODILE \\ Incorporating medium-resolution spectroscopy of close-in directly imaged exoplanets into atmospheric retrievals via cross-correlation
• Constraints on the gas-phase C/O ratio of DR Tau's outer disk from CS, SO, and C${}_2$H observations
• PACOME: Optimal multi-epoch combination of direct imaging observations for joint exoplanet detection and orbit estimation
• High-contrast spectroscopy with the new VLT/ERIS instrument: Molecular maps and radial velocity of the gas giant AF Lep b
• Distinct Rotational Evolution of Giant Planets and Brown Dwarf Companions
• A High-Resolution Spectroscopic Survey of Directly Imaged Companion Hosts: II. Diversity in C/O Ratios among Host Stars
• JWST-TST High Contrast: First Direct Spectroscopy of GJ 504 b reveals Clouds and Possible Metal Enrichment