Keplerian motion of a compact source orbiting the inner disc of PDS 70: a third protoplanet in resonance with b and c?

Abstract

The disc around PDS 70 hosts two directly imaged protoplanets in a gap. Previous VLT/SPHERE and recent James Webb Space Telescope/NIRCam observations have hinted at the presence of a third compact source in the same gap at ~13 au, interior to the orbit of PDS 70 b. We reduce seven published and one unpublished VLT/SPHERE datasets in YJH and K bands, as well as an archival VLT/NaCo dataset in L' band, and an archival VLT/SINFONI dataset in H+K band. We combine angular-, spectral- and reference star differential imaging to search for protoplanet candidates. We recover the compact source in all epochs, consistent with the JWST detection, moving on an arc that can be fit by Keplerian motion of a protoplanet which could be in a resonance with PDS 70 b & c. We find that the spectral slope is overall consistent with the unresolved star and inner disc emission at 0.95--1.65$\mu$m, which suggests a dust scattering dominated spectrum. An excess beyond 2.3$\mu$m could be thermal emission from either a protoplanet or heated circumplanetary dust, variability, or inner disc contamination, and requires confirmation. While we currently cannot rule out a moving inner disc feature or a dust clump associated with an unseen planet, the data supports the hypothesis of a third protoplanet in this remarkable system.

V2: Minor update of title to match MNRAS. Accepted for publication in MNRAS, 15 pages. FITS files are available at: https://keeper.mpdl.mpg.de/d/2633616c51b64433962d/

References in corpus (41)

• Gaia Data Release 3: Summary of the content and survey properties
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Two accreting protoplanets around the young star PDS 70
• A Circumplanetary Disk Around PDS70c
• VIP: Vortex Image Processing package for high-contrast direct imaging
• Highly structured disk around the planet host PDS 70 revealed by high-angular resolution observations with ALMA
• Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY
• Water in the terrestrial planet-forming zone of the PDS 70 disk
• VLT/SPHERE exploration of the young multiplanetary system PDS70
• Keck/NIRC2 $L$'-Band Imaging of Jovian-Mass Accreting Protoplanets around PDS 70
• Evidence for a circumplanetary disk around protoplanet PDS 70 b
• VLT/SPHERE robust astrometry of the HR8799 planets at milliarcsecond-level accuracy Orbital architecture analysis with PyAstrOFit
• Accurate Astrometry and Photometry of Saturated and Coronagraphic Point Spread Functions
• Confirmation and Keplerian motion of the gap-carving protoplanet HD 169142 b
• Observability of Forming Planets and their Circumplanetary Disks II. -- SEDs and Near-Infrared Fluxes
• The SPHERE infrared survey for exoplanets (SHINE)- I Sample definition and target characterization
• Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI
• A search for a 5th planet around HR 8799 using the star-hopping RDI technique at VLT/SPHERE
• Reference-star differential imaging on SPHERE/IRDIS
• MAYONNAISE: a morphological components analysis pipeline for circumstellar disks and exoplanets imaging in the near infrared
• Protoplanetary disks in $K_s$-band total intensity and polarized light
• An exact, generalised Laplace resonance in the HR 8799 planetary system
• Planet migration, resonant locking and accretion streams in PDS70: Comparing models and data
• MINDS: JWST/NIRCam imaging of the protoplanetary disk PDS 70
• Dust mineralogy and variability of the inner PDS 70 disk
• Octofitter: Fast, Flexible, and Accurate Orbit Modelling to Detect Exoplanets
• 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
• Analysis of the arm-like structure in the outer disk of PDS 70. Spiral density wave or vortex?
• Evidence for Variable Accretion onto PDS 70 c and Implications for Protoplanet Detections
• Tentative co-orbital submillimeter emission within the Lagrangian region L5 of the protoplanet PDS 70 b
• A faint companion around CrA-9: protoplanet or obscured binary?
• PDS 70 unveiled by star-hopping: total intensity, polarimetry and mm-imaging modeled in concert
• Inverse-problem versus principal component analysis methods for angular differential imaging of circumstellar disks. The mustard algorithm
• Combining reference-star and angular differential imaging for high-contrast imaging of extended sources
• Spectral and angular differential imaging with SPHERE/IFS. Assessing the performance of various PCA-based approaches to PSF subtraction
• Photoevaporation of the Jovian circumplanetary disk I. Explaining the orbit of Callisto and the lack of outer regular satellites
• Karhunen-Loève Data Imputation in High Contrast Imaging
• Observing Circumplanetary Disks with METIS
• Pigeons.jl: Distributed Sampling From Intractable Distributions
• Spectral cube extraction for the VLT/SPHERE IFS: Open-source pipeline with full forward modeling and improved sensitivity
• Parallel Tempering With a Variational Reference

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• Differentiating Formation Models with New Dynamical Masses for the PDS 70 Protoplanets
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• Semianalytical Accretion-Tracer Emission: Forming Planets Are Intrinsically Faint
• Reading between the rings: observed dust ring properties as probes of planet masses
• Potential sublimating exocomets around the young star PDS 70
• Searching for Embedded Protoplanets with the Keck/NIRC2 Vortex Coronagraph: Confirmation of a Core-accretion Planet in the Narrow Gap of the Elias 2-24 Disk