The Planetary Luminosity Problem: "Missing Planets" and the Observational Consequences of Episodic Accretion

Abstract

The high occurrence rates of spiral arms and large central clearings in protoplanetary disks, if interpreted as signposts of giant planets, indicate that gas giants form commonly as companions to young stars ($<$ few Myr) at orbital separations of 10--300\,au. However, attempts to directly image this giant planet population as companions to more mature stars ($>10$\, Myr) have yielded few successes. This discrepancy could be explained if most giant planets form "cold start," i.e., by radiating away much of their formation energy as they assemble their mass, rendering them faint enough to elude detection at later times. In that case, giant planets should be bright at early times, during their accretion phase, and yet forming planets are detected only rarely through direct imaging techniques. Here we explore the possibility that the low detection rate of accreting planets is the result of episodic accretion through a circumplanetary disk. We also explore the possibility that the companion orbiting the Herbig Ae star HD~142527 may be a giant planet undergoing such an accretion outburst.

17 pages, 2 figures, accepted by ApJ

References in corpus (30)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• One or more bound planets per Milky Way star from microlensing observations
• On the Luminosity of Young Jupiters
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• Two accreting protoplanets around the young star PDS 70
• Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets
• Shadows cast by a warp in the HD 142527 protoplanetary disk
• Synthetic Spectra and Colors of Young Giant Planet Atmospheres: Effects of Initial Conditions and Atmospheric Metallicity
• Submillimeter emission associated with candidate protoplanets
• Accreting Circumplanetary Disks: Observational Signatures
• No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals
• Searching for circumplanetary disks around LkCa 15
• NIR Spectroscopy of the HAeBe Star HD 100546: III. Further Evidence of an Orbiting Companion?
• Resolving the planet-hosting inner regions of the LkCa 15 disk
• Investigation of the inner structures around HD169142 with VLT/SPHERE
• Effects of the Planetary Temperature on the Circumplanetary Disk and on the Gap
• A Model-Independent Mass and Moderate Eccentricity for $\beta$ Pic b
• Thermodynamics of Giant Planet Formation: Shocking Hot Surfaces on Circumplanetary Disks
• Observability of Forming Planets and their Circumplanetary Disks II. -- SEDs and Near-Infrared Fluxes
• The widest H$\alpha$ survey of accreting protoplanets around nearby transition disks
• Blobs, spiral arms, and a possible planet around HD 169142
• Shock-driven Accretion in Circumplanetary Disks: Observables and Satellite Formation
• SPHERE dynamical and spectroscopic characterization of HD142527B
• Characterization of the inner disk around HD 141569 A from Keck/NIRC2 L-band vortex coronagraphy
• Stellar parameters and accretion rate of the transition disk star HD 142527 from X-Shooter
• Spectral Energy Distributions of Accreting Protoplanets
• Spiral Structure and Differential Dust Size Distribution in the LkHa 330 Disk
• The temporal requirements of directly observing self-gravitating spiral waves in protoplanetary discs with ALMA
• No Transition Disk? Infrared Excess, PAH, H2, and X-rays from the Weak-Lined T Tauri Star DoAr 21
• Near Infrared High Resolution Spectroscopy and Spectro-astrometry of Gas in Disks around Herbig Ae/Be Stars

Cited by in corpus (31)

• On the diversity of asymmetries in gapped protoplanetary disks
• Hubble Space Telescope UV and H$\alpha$ Measurements of the Accretion Excess Emission from the Young Giant Planet PDS 70 b
• Perturbers: SPHERE detection limits to planetary-mass companions in protoplanetary disks
• Comparison of planetary Hα-emission models: A new correlation with accretion luminosity
• Predicting the kinematic evidence of gravitational instability
• Transition disks: the observational revolution from SEDs to imaging
• Accreting protoplanets: Spectral signatures and magnitude of gas and dust extinction at H alpha
• ALMA Detection of Dust Trapping around Lagrangian Points in the LkCa 15 Disk
• Dynamical Evidence of a Spiral Arm--Driving Planet in the MWC 758 Protoplanetary Disk
• Herbig Stars: A Quarter Century of Progress
• Emission line variability of young 10-30 Mjup companions : I. The case of GQ Lup b and GSC 06214-00210 b
• N-body simulations of planet formation via pebble accretion II. How various giant planets form
• Searching for H${}_{\alpha }$-emitting sources in the gaps of five transitional disks. SPHERE/ZIMPOL high-contrast imaging
• The Planetary Accretion Shock. III. Smoothing-free 2.5D simulations and calculation of H alpha emission
• 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
• Spiral Arm Pattern Motion in the SAO 206462 Protoplanetary Disk
• The Separation and H-alpha Contrasts of Massive Accreting Planets in the Gaps of Transitional Disks: Predicted H-alpha Protoplanet Yields for Adaptive Optics Surveys
• Boundary Layer Circumplanetary Accretion: How Fast Could an Unmagnetized Planet Spin Up Through Its Disk?
• Stellar Flyby Analysis for Spiral Arm Hosts with Gaia DR3
• Exciting spiral arms in protoplanetary discs from flybys
• Evidence for Variable Accretion onto PDS 70 c and Implications for Protoplanet Detections
• Revisiting the Helium and Hydrogen Accretion Indicators at TWA 27B: Weak Mass Flow at Near-Freefall Velocity
• Gap Opening and Inner Disk Structure in the Strongly Accreting Transition Disk of DM Tau
• Dust rings as a footprint of planet formation in a protoplanetary disk
• Observing Circumplanetary Disks with METIS
• Searching for wide-orbit gravitational instability protoplanets with ALMA in the dust continuum
• UV Spectropolarimetry with Polstar: Protoplanetary Disks
• The evolution of a circumplanetary disc with a dead zone
• Kozai-Lidov oscillations triggered by a tilt instability of detached circumplanetary discs
• Occurrence rates of accreting companions from a new method for computing emission-line survey sensitivity: application to the H-alpha Giant Accreting Protoplanet Survey
• Semianalytical Accretion-Tracer Emission: Forming Planets Are Intrinsically Faint