VLT/SPHERE robust astrometry of the HR8799 planets at milliarcsecond-level accuracy Orbital architecture analysis with PyAstrOFit

Abstract

HR8799 is orbited by at least four giant planets, making it a prime target for the recently commissioned Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT/SPHERE). As such, it was observed on five consecutive nights during the SPHERE science verification in December 2014. We aim to take full advantage of the SPHERE capabilities to derive accurate astrometric measurements based on H-band images acquired with the Infra-Red Dual-band Imaging and Spectroscopy (IRDIS) subsystem, and to explore the ultimate astrometric performance of SPHERE in this observing mode. We also aim to present a detailed analysis of the orbital parameters for the four planets. We report the astrometric positions for epoch 2014.93 with an accuracy down to 2.0 mas, mainly limited by the astrometric calibration of IRDIS. For each planet, we derive the posterior probability density functions for the six Keplerian elements and identify sets of highly probable orbits. For planet d, there is clear evidence for nonzero eccentricity ($e\simeq 0.35$), without completely excluding solutions with smaller eccentricities. The three other planets are consistent with circular orbits, although their probability distributions spread beyond $e=0.2$, and show a peak at $e\simeq 0.1$ for planet e. The four planets have consistent inclinations of about $30°$ with respect to the sky plane, but the confidence intervals for the longitude of ascending node are disjoint for planets b and c, and we find tentative evidence for non-coplanarity between planets b and c at the $2\sigma$ level.

arXiv comment23 pages, 14 figures

References in corpus (49)

• emcee: The MCMC Hammer
• Validation of the new Hipparcos reduction
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Angular Differential Imaging: a Powerful High-Contrast Imaging Technique
• Images of a fourth planet orbiting HR 8799
• A giant planet imaged in the disk of the young star Beta Pictoris
• Detection and Characterization of Exoplanets and Disks using Projections on Karhunen-Loeve Eigenimages
• Improving the Efficiency of Markov Chain Monte Carlo for Analyzing the Orbits of Extrasolar Planets
• A new algorithm for point spread function subtraction in high-contrast imaging: a demonstration with angular differential imaging
• Quantifying the Uncertainty in the Orbits of Extrasolar Planets
• Fundamental limitations of high contrast imaging set by small sample statistics
• PynPoint: An Image Processing Package for Finding Exoplanets
• A Combined Subaru/VLT/MMT 1--5 Micron Study of Planets Orbiting HR 8799: Implications for Atmospheric Properties, Masses, and Formation
• The Debris Disk Around HR 8799
• Improving Galactic Center Astrometry by Reducing the Effects of Geometric Distortion
• Apodized Pupil Lyot Coronagraphs for Arbitrary Telescope Apertures
• First light of the VLT planet finder SPHERE. III. New spectrophotometry and astrometry of the HR8799 exoplanetary system
• Orbital characterization of the βPictoris b giant planet
• STIS Coronagraphic Imaging of Fomalhaut: Main Belt Structure and the Orbit of Fomalhaut b
• Stability of the directly imaged multiplanet system HR 8799: resonance and masses
• First light of the VLT planet finder SPHERE. IV. Physical and chemical properties of the planets around HR8799
• HST/NICMOS detection of HR 8799 b in 1998
• M-band Imaging of the HR 8799 Planetary System Using an Innovative LOCI-based Background Subtraction Technique
• Reconnaissance of the HR 8799 Exosolar System II: Astrometry and Orbital Motion
• Resolved Imaging of the HR 8799 Debris Disk with Herschel
• Thermal Infrared MMTAO Observations of the HR 8799 Planetary System
• Magellan Adaptive Optics first-light observations of the exoplanet beta Pic b. II. 3-5 micron direct imaging with MagAO+Clio, and the empirical bolometric luminosity of a self-luminous giant planet
• 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
• Multiple mean motion resonances in the HR 8799 planetary system
• SPHERE IRDIS and IFS astrometric strategy and calibration
• Astrometric Monitoring of the HR 8799 Planets: Orbit Constraints from Self-Consistent Measurements
• High-Cadence, High-Contrast Imaging for Exoplanet Mapping: Observations of the HR 8799 Planets with VLT/SPHERE Satellite Spot-Corrected Relative Photometry
• LBT observations of the HR 8799 planetary system: First detection of HR8799e in H band
• Low-rank plus sparse decomposition for exoplanet detection in direct-imaging ADI sequences. The LLSG algorithm
• 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
• Is the HR 8799 extrasolar system destined for planetary scattering?
• The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system
• Direct Detection and Orbit Analysis of the Exoplanets HR 8799 bcd from Archival 2005 Keck/NIRC2 Data
• H band Image of a Planetary Companion around HR 8799 in 2002
• Optimized Principal Component Analysis on Coronagraphic Images of the Fomalhaut System
• Pre-Discovery 2007 Image of the HR 8799 Planetary System
• High precision astrometry with a diffractive pupil telescope
• VLT/NACO astrometry of the HR8799 planetary system. L'-band observations of the three outer planets
• Long-term stability of the HR 8799 planetary system without resonant lock
• Discovery of a low-mass companion around HR3549
• A high precision technique to correct for residual atmospheric dispersion in high-contrast imaging systems

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• Debris Disks: Structure, Composition, and Variability
• VIP: Vortex Image Processing package for high-contrast direct imaging
• orbitize!: A Comprehensive Orbit-fitting Software Package for the High-contrast Imaging Community
• Dynamical Constraints on the HR 8799 Planets with GPI
• MIRACLES: atmospheric characterization of directly imaged planets and substellar companions at 4-5 $\mu$m. I. Photometric analysis of $\beta$ Pic b, HIP 65426 b, PZ Tel B and HD 206893 B
• orvara: An Efficient Code to Fit Orbits using Radial Velocity, Absolute, and/or Relative Astrometry
• Discovery of a low-mass companion inside the debris ring surrounding the F5V star HD206893
• Radial Velocity Measurements of HR 8799 b and c with Medium Resolution Spectroscopy
• Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1
• In-depth study of moderately young but extremely red, very dusty substellar companion HD206893B
• PynPoint: a modular pipeline architecture for processing and analysis of high-contrast imaging data
• GPI spectra of HR 8799 c, d, and e from 1.5 to 2.4$\mu$m with KLIP Forward Modeling
• A survey of the linear polarization of directly imaged exoplanets and brown dwarf companions with SPHERE-IRDIS. First polarimetric detections revealing disks around DH Tau B and GSC 6214-210 B
• Deep exploration of the planets HR 8799 b, c, and d with moderate resolution spectroscopy
• Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI
• Polarized scattered light from self-luminous exoplanets. Three-dimensional scattering radiative transfer with ARTES
• A detailed characterization of HR 8799's debris disk with ALMA in Band 7
• Discovery of a directly imaged planet to the young solar analog YSES 2
• On the Chemical Abundance of HR 8799 and the Planet c
• Orbital and dynamical analysis of the system around HR 8799. New astrometric epochs from VLT/SPHERE and LBT/LUCI
• A New Standard for Assessing the Performance of High Contrast Imaging Systems
• 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
• Detecting Water In the atmosphere of HR 8799 c with L-band High Dispersion Spectroscopy Aided By Adaptive Optics
• MINDS: JWST/NIRCam imaging of the protoplanetary disk PDS 70
• Characterization of low-mass companion HD 142527 B
• ISPY-NACO Imaging Survey for Planets around Young stars. The demographics of forming planets embedded in protoplanetary disks
• The orbital architecture and debris disks of the HR 8799 planetary system
• Occurrence Rates from Direct Imaging Surveys
• Dynamical Mass of the Exoplanet Host Star HR 8799
• Surveying Nearby Brown Dwarfs with HGCA: Direct Imaging Discovery of a Faint, High-Mass Brown Dwarf Orbiting HD 176535 A
• Deep orbital search for additional planets in the HR 8799 system
• WEIRD: Wide-orbit Exoplanet search with InfraRed Direct imaging
• Multiple Populations of Extrasolar Gas Giants
• The GALAH Survey: Lithium-strong KM dwarfs
• A faint companion around CrA-9: protoplanet or obscured binary?
• The ALMA survey to Resolve exoKuiper belt Substructures (ARKS): VI. Asymmetries and offsets
• The SHARDDS survey: limits on planet occurrence rates based on point sources analysis via the Auto-RSM framework
• Detection of H$\alpha$ emission from PZ Tel B using SPHERE/ZIMPOL
• Keplerian motion of a compact source orbiting the inner disc of PDS 70: a third protoplanet in resonance with b and c?
• ISPY - the NaCo Imaging Survey for Planets around Young stars: A young companion candidate embedded in the R CrA cloud
• On-sky closed loop correction of atmospheric dispersion for high-contrast coronagraphy and astrometry
• Dynamical Masses and Ages of Sirius-like Systems
• PACOME: Optimal multi-epoch combination of direct imaging observations for joint exoplanet detection and orbit estimation
• Astrometric and photometric characterization of $\eta$ Tel B combining two decades of observations
• An Alternating Minimization Algorithm with Trajectory for Direct Exoplanet Detection -- The AMAT Algorithm
• Direct Imaging Discovery of Giant Exoplanet $\beta$ Pictoris d: A Decade-Long Game of Hide-and-Seek
• Improving the RSM map exoplanet detection algorithm: PSF forward modelling and optimal selection of PSF subtraction techniques
• Low-mass stellar and substellar candidate companions around massive stars in Sco OB1 and M17
• Special cases : moons, rings, comets, trojans