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

Abstract

We present high-contrast imaging observations of seven stars obtained with the Keck/NIRC2 vortex coronagraph between 2018 May and June in the $L^{\prime }$ and $M_s$ bands. All targets host protoplanetary disks with substructures such as gaps and cavities, potentially tracing ongoing planet formation. Our aim is to assess whether these embedded planets can be directly detected. We reduced the observations with a custom pipeline based on the VIP Python package. Postprocessed images were obtained using angular differential imaging and reference differential imaging combined with principal component analysis. Finally, 5$\sigma$ contrast curves and detection limits were derived for all targets. We confirm the planetary candidate around Elias 2-24, previously proposed in the literature, at a separation of 394$\pm$31 mas (54.9$\pm 4$.3 au) and a position angle of 298.8$\pm$3.2${}^{\circ }$, within the narrow gap of the protoplanetary disk. Comparing the derived photometry with 1 Myr isochrones, we infer a mass between 1.9 and 4.0 Jupiter masses for Elias 2-24 b, without considering accretion effects, in agreement with estimates considering the properties of the gap and planet-disk interactions. For all the systems in the survey, the 5$\sigma$ detection limits reach sensitivities down to 1-11 Jupiter masses at separations $\gtrsim$0.25". Since Elias 2-24 b (age $\lesssim$1 Myr) is the youngest exoplanet discovered to date, its confirmation has important implications for planet formation timescales and the origin of the gaps observed in very young disks.

References in corpus (77)

• Gaia Data Release 3: Summary of the content and survey properties
• Validation of the new Hipparcos reduction
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• 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
• Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70
• On the Luminosity of Young Jupiters
• Two accreting protoplanets around the young star PDS 70
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• Protoplanetary Disk Structures in Ophiuchus II: Extension to Fainter Sources
• Observations of Protoplanetary Disk Structures
• The Star-formation History and Accretion-Disk Fraction Among the K-Type Members of the Scorpius-Centaurus OB Association
• The Disk Substructures at High Angular Resolution Project (DSHARP): VII. The Planet-Disk Interactions Interpretation
• Fundamental limitations of high contrast imaging set by small sample statistics
• Molecules with ALMA at Planet-forming Scales (MAPS) I: Program Overview and Highlights
• Population Properties of Brown Dwarf Analogs to Exoplanets
• Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk
• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• The Hawaii Infrared Parallax Program. II. Young Ultracool Field Dwarfs
• Dust grain growth in rho-Ophiuchi protoplanetary disks
• Challenges in Forming Planets by Gravitational Instability: Disk Irradiation and Clump Migration, Accretion & Tidal Destructio
• The Ophiuchus DIsc Survey Employing ALMA (ODISEA) - I : project description and continuum images at 28 au resolution
• VIP: Vortex Image Processing package for high-contrast direct imaging
• Submillimeter emission associated with candidate protoplanets
• Accreting Circumplanetary Disks: Observational Signatures
• The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b
• Polarimetric Imaging of Large Cavity Structures in the Pre-transitional Protoplanetary Disk around PDS 70: Observations of the disk
• The Besancon Galaxy model renewed I. Constraints on the local star formation history from Tycho data
• Planet formation signposts: observability of circumplanetary disks via gas kinematics
• The Ophiuchus DIsc Survey Employing ALMA (ODISEA)-III: the evolution of substructures in massive discs at 3-5 au resolution
• Direct confirmation of the radial-velocity planet $\beta$ Pic c
• Characterization of exoplanets from their formation III: The statistics of planetary luminosities
• Luminosity of young Jupiters revisited. Massive cores make hot planets
• Rings and gaps in the disc around Elias 24 revealed by ALMA
• The time evolution of dusty protoplanetary disc radii: observed and physical radii differ
• The Ophiuchus DIsk Survey Employing ALMA (ODISEA): Disk Dust Mass Distributions across Protostellar Evolutionary Classes
• VLT/SPHERE exploration of the young multiplanetary system PDS70
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. III. Substructures in Protostellar Disks
• Disks Around T Tauri Stars with SPHERE (DARTTS-S) II: Twenty-one new polarimetric images of young stellar disks
• Impact of a new H/He equation of state on the evolution of massive brown dwarfs. New determination of the hydrogen burning limit
• Observability of planet-disc interactions in CO kinematics
• Reference star differential imaging of close-in companions and circumstellar disks with the NIRC2 vortex coronagraph at W.M. Keck Observatory
• The W. M. Keck Observatory infrared vortex coronagraph and a first image of HIP79124 B
• Confirmation and Keplerian motion of the gap-carving protoplanet HD 169142 b
• Disk Substructures at High Angular Resolution Program (DSHARP): VIII. The Rich Ringed Substructures in the AS 209 Disk
• Molecules with ALMA at Planet-forming Scales (MAPS). A Circumplanetary Disk Candidate in Molecular Line Emission in the AS 209 Disk
• The widest H$\alpha$ survey of accreting protoplanets around nearby transition disks
• Post-coronagraphic tip-tilt sensing for vortex phase masks: the QACITS technique
• The Planetary Accretion Shock: I. Framework for Radiation-hydrodynamical Simulations and First Results
• V1094 Sco: a rare giant multi-ringed disk around a T Tauri star
• The Planetary Accretion Shock. II. Grid of Post-Shock Entropies and Radiative Shock Efficiencies for Non-Equilibrium Radiation Transport
• Differences in the gas and dust distribution in the transitional disk of a sun-like young star, PDS 70
• A WISE Survey of Circumstellar disks in the Upper Scorpius Association
• Exploring the formation by core accretion and the luminosity evolution of directly imaged planets: The case of HIP 65426 b
• ALMA observations of Elias 2-24: a protoplanetary disk with multiple gaps in the Ophiuchus Molecular Cloud
• On-sky performance of the QACITS pointing control technique with the Keck/NIRC2 vortex coronagraph
• The gravitational mass of Proxima Centauri measured with SPHERE from a microlensing event
• Dynamical Mass of the Young Substellar Companion HD 984 B
• WIde Separation Planets In Time (WISPIT): A Gap-clearing Planet in a Multi-ringed Disk around the Young Solar-type Star WISPIT 2
• ISPY-NACO Imaging Survey for Planets around Young stars. The demographics of forming planets embedded in protoplanetary disks
• A high-resolution survey of protoplanetary disks in Lupus and the nature of compact disks
• A scaled-up planetary system around a supernova progenitor
• Comparing Apples with Apples: Robust Detection Limits for Exoplanet High-Contrast Imaging in the Presence of non-Gaussian Noise
• A search for companions via direct imaging in the DSHARP planet-forming disks
• Molecules with ALMA at Planet-forming Scales (MAPS). Complex Kinematics in the AS 209 Disk Induced by a Forming Planet and Disk Winds
• A kinematic excess in the annular gap and gas depleted cavity in the disc around HD 169142
• Kinematic and thermal signatures of the directly imaged protoplanet candidate around Elias 2-24
• Transition disks: 4 candidates for ongoing giant planet formation in Ophiuchus (Research Note)
• CAMPOS II. The onset of protostellar disk substructures and planet formation
• Keplerian motion of a compact source orbiting the inner disc of PDS 70: a third protoplanet in resonance with b and c?
• The Ophiuchus DIsk Survey Employing ALMA (ODISEA): A Unified Evolutionary Sequence of Planet-Driven Substructures Explaining the Diversity of Disk Morphologies
• Kinematics signature of a giant planet in the disk of AS 209
• Astrometric view of companions in the inner dust cavities of protoplanetary disks
• Gaps and Rings: A Near-Universal Trait of Extended Protoplanetary Discs