Efficiently Imaging Accreting Protoplanets from Space: Reference Star Differential Imaging of the PDS 70 Planetary System using the HST/WFC3 Archival PSF Library

Abstract

Accreting protoplanets provide key insights into how planets assemble from their natal protoplanetary disks. Recently, Zhou et al. (2021) used angular differential imaging (ADI) with Hubble Space Telescope's Wide Field Camera 3 (HST/WFC3) to recover the young accreting planet PDS 70 b in F656N ($\mathrm{H}\alpha$) at a S/N of 7.9. In this paper, we demonstrate a promising approach to efficiently imaging accreting planets by applying reference star differential imaging (RDI) to the same dataset. We compile a reference library from the database of WFC3 point-spread functions (PSFs) provided by Space Telescope Science Institute and develop a set of morphology-significance criteria for pre-selection of reference frames to improve RDI subtraction. RDI with this PSF library results in a detection of PDS 70 b at a S/N of 5.3. Astrometry and photometry of PDS 70 b are calibrated using a forward-modeling method and injection-recovery tests, resulting in a separation of $186\pm 13$ mas, a position angle of $142\pm 5^{\circ }$, and an H$\alpha$ flux of $(1.7\pm 0.3)\times 10^{-15}$ erg s${}^{-1}$ cm${}^{-2}$. The lower detection significance with RDI can be attributed to the $\sim$100 times lower peak-to-background ratios of the reference PSFs compared to the ADI PSFs. Building a high-quality reference library with WFC3 will provide unique opportunities to study accretion variability on short timescales not limited by roll angle scheduling constraints and efficiently search for actively accreting protoplanets in $\mathrm{H}\alpha$ around targets inaccessible to ground-based adaptive optics systems, such as faint transition disk hosts.

arXiv commentAccepted for publication in The Astronomical Journal, 20 pages, 12 figures, 1 table

References in corpus (65)

• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Angular Differential Imaging: a Powerful High-Contrast Imaging Technique
• A giant planet imaged in the disk of the young star Beta Pictoris
• The MUSE second-generation VLT instrument
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• Detection and Characterization of Exoplanets and Disks using Projections on Karhunen-Loeve Eigenimages
• Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70
• Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini Planet Imager
• Gravitational Instabilities in Circumstellar Disks
• On the Luminosity of Young Jupiters
• Two accreting protoplanets around the young star PDS 70
• The Subaru Coronagraphic Extreme Adaptive Optics system: enabling high-contrast imaging on solar-system scales
• The Star-formation History and Accretion-Disk Fraction Among the K-Type Members of the Scorpius-Centaurus OB Association
• Fundamental limitations of high contrast imaging set by small sample statistics
• Imaging Extrasolar Giant Planets
• Theoretical Limits on Extrasolar Terrestrial Planet Detection with Coronagraphs
• Accreting Protoplanets in the LkCa 15 Transition Disk
• Observational Signatures of Planets in Protoplanetary Disks I: Gaps Opened by Single and Multiple Young Planets in Disks
• A Circumplanetary Disk Around PDS70c
• Probing for Exoplanets Hiding in Dusty Debris Disks: Disk Imaging, Characterization, and Exploration with HST/STIS Multi-Roll Coronagraphy
• Near-Infrared Spectroscopy of the Extrasolar Planet HR 8799 b
• Submillimeter emission associated with candidate protoplanets
• Detection and Characterization of Exoplanets using Projections on Karhunen-Loeve Eigenimages: Forward Modeling
• Magellan Adaptive Optics Imaging of PDS 70: Measuring the Mass Accretion Rate of a Young Giant Planet within a Gapped Disk
• Polarimetric Imaging of Large Cavity Structures in the Pre-transitional Protoplanetary Disk around PDS 70: Observations of the disk
• Highly structured disk around the planet host PDS 70 revealed by high-angular resolution observations with ALMA
• Substructure in the Circumstellar Disk around the Young Star AU Mic (GJ 803)
• STIS Coronagraphic Imaging of Fomalhaut: Main Belt Structure and the Orbit of Fomalhaut b
• HST/NICMOS detection of HR 8799 b in 1998
• SPHERE / ZIMPOL high resolution polarimetric imager. I. System overview, PSF parameters, coronagraphy, and polarimetry
• Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY
• The M31 Velocity Vector. I. Hubble Space Telescope Proper Motion Measurements
• Accretion onto Planetary Mass Companions of Low-Mass Young Stars
• Combining Undersampled Dithered Images
• Disk evolution, element abundances and cloud properties of young gas giant planets
• High-Contrast Observations in Optical and Infrared Astronomy
• High-efficiency Autonomous Laser Adaptive Optics
• 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
• Keck/NIRC2 $L$'-Band Imaging of Jovian-Mass Accreting Protoplanets around PDS 70
• Theoretical Model of Hydrogen Line Emission from Accreting Gas Giants
• Accretion Properties of PDS 70b with MUSE
• Investigation of the inner structures around HD169142 with VLT/SPHERE
• Reference star differential imaging of close-in companions and circumstellar disks with the NIRC2 vortex coronagraph at W.M. Keck Observatory
• Hubble Space Telescope UV and H$\alpha$ Measurements of the Accretion Excess Emission from the Young Giant Planet PDS 70 b
• Magellan Adaptive Optics first-light observations of the exoplanet $\beta$ Pic b. I. Direct imaging in the far-red optical with MagAO+VisAO and in the near-IR with NICI
• Five Debris Disks Newly Revealed in Scattered Light from the HST NICMOS Archive
• HST NICMOS Imaging of the Planetary-mass Companion to the Young Brown Dwarf 2MASS J1207334-393254
• Characterizing the performance of the NIRC2 vortex coronagraph at W.M. Keck Observatory
• Magnetospheric Accretion as a Source of H$\alpha$ Emission from Proto-planets around PDS 70
• The Planetary Accretion Shock: I. Framework for Radiation-hydrodynamical Simulations and First Results
• Giant planet and brown dwarf formation
• SPHERE dynamical and spectroscopic characterization of HD142527B
• New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
• Deep imaging search for planets forming in the TW Hya protoplanetary disk with the Keck/NIRC2 vortex coronagraph
• Variable Accretion onto Protoplanet Host Star PDS 70
• Direct characterization of young giant exoplanets at high spectral resolution by coupling SPHERE and CRIRES+
• Cloud Atlas: High-Contrast Time-Resolved Observations of Planetary-Mass Companions
• Formation and evolution of planetary systems: the impact of high angular resolution optical techniques
• The Gemini Planet Imager view of the HD 32297 debris disk
• Characterizing the Atmospheres of the HR8799 Planets with HST/WFC3
• Enabling Narrow(est) IWA Coronagraphy with STIS BAR5 and BAR10 Occulters
• An HST/STIS View of Protoplanetary Disks in Upper Scorpius: Observations of Three Young M-Stars
• High-contrast imaging in the Hyades with snapshot LOCI

Cited by in corpus (9)

• The JWST Early Release Science Program for the Direct Imaging & Spectroscopy of Exoplanetary Systems
• HST/WFC3 H$\alpha$ Direct-Imaging Detection of a Point-like Source in the Disk Cavity of AB Aur
• Reference-star differential imaging on SPHERE/IRDIS
• The Giant Accreting Protoplanet Survey (GAPlanetS) -- Results from a Six Year Campaign to Image Accreting Protoplanets
• Three Years of High-Contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dust
• The Planetary Accretion Shock. III. Smoothing-free 2.5D simulations and calculation of H alpha emission
• Worlds Next Door: A Candidate Giant Planet Imaged in the Habitable Zone of $\alpha$ Cen A. II. Binary Star Modeling, Planet and Exozodi Search, and Sensitivity Analysis
• PACOME: Optimal multi-epoch combination of direct imaging observations for joint exoplanet detection and orbit estimation
• Companion Mass Limits for 17 Binary Systems Obtained with Binary Differential Imaging and MagAO/Clio