Kinks and Dents in Protoplanetary Disks: Rapid Infrared Variability as Evidence for Large Structural Perturbations

Abstract

We report on synoptic observations at 3.6 and 4.5micron of young stellar objects in IC 348 with 38 epochs covering 40 days. We find that among the detected cluster members, 338 at [3.6] and 269 at both [3.6] and [4.5], many are variable on daily to weekly timescales with typical fluctuations of ~0.1 mag. The fraction of variables ranges from 20% for the diskless pre-main sequence stars to 60% for the stars still surrounded by infalling envelopes. We also find that stars in the exposed cluster core are less variable than the stars in the dense, slightly younger, south-western ridge. This trend persists even after accounting for the underlying correlation with infrared SED type, suggesting that the change in variable fraction is not simply a reflection of the change in relative fraction of class I vs. class II sources across the cloud, but instead reflects a change in variability with age. We also see a strong correlation between infrared variability and X-ray luminosity among the class II sources. The observed variability most likely reflects large changes in the structure of the inner wall located at the dust sublimation radius. We explore the possibility that these structural perturbations could be caused by a hot spot on the star heating dust above the sublimation temperature, causing it to evaporate rapidly, and increasing the inner radius for a portion of the disk. Under a number of simplifying assumptions we show that this model can reproduce the size and timescale of the 3.6 and 4.5micron fluctuations. Regardless of its source, the infrared variability indicates that the inner disk is not a slowly evolving entity, but instead is a bubbling, warped, dented mass of gas and dust whose global size and shape fluctuate in a matter of days.

Accepted to AJ. 25 pages, 24 figures (+75 additional online figures and 3 online tables)

References in corpus (18)

• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• The Spitzer Space Telescope Survey of the Orion A & B Molecular Clouds - Part I: A Census of Dusty Young Stellar Objects and a Study of their Mid-IR Variability
• Magnetospheric accretion-ejection processes in the classical T Tauri star AA
• Accretion to Magnetized Stars through the Rayleigh-Taylor Instability: Global Three-Dimensional Simulations
• A Spitzer census of the IC 348 nebula
• Current Star Formation in the Ophiuchus and Perseus Molecular Clouds: Constraints and Comparisons from Unbiased Submillimeter and Mid-Infrared Surveys. II
• A Correlation Between Pre-Main Sequence Stellar Rotation Rates and IRAC Excesses in Orion
• Variability of Disk Emission in Pre-Main Sequence and Related Stars. I. HD 31648 and HD 163296 - Isolated Herbig Ae Stars Driving Herbig-Haro Flows
• A statistical analysis of X-ray variability in pre-main sequence objects of the Taurus Molecular Cloud
• Testing the Disk Regulation Paradigm with Spitzer Observations. I. Rotation Periods of Pre-main Sequence Stars in the IC 348 Cluster
• Pulsed Accretion in a Variable Protostar
• YSOVAR: Six pre-main-sequence eclipsing binaries in the Orion Nebula Cluster
• A 1.3 cm wavelength radio flare from a deeply embedded source in the Orion BN/KL region
• The Variability and Rotation of Pre-main Sequence Stars in IC 348: Does Intracluster Environment Influence Stellar Rotation?
• Long-term infrared variability of the UX Ori-type star SV Cep
• Star formation in the vicinity of the IC 348 cluster
• ISM Dust Grains and N-band Spectral Variability in the Spatially Resolved Subarcsecond Binary UY Aur

Cited by in corpus (27)

• Circumstellar Disk Lifetimes In Numerous Galactic Young Stellar Clusters
• A Census of Young Stars and Brown Dwarfs in IC 348 and NGC 1333
• Young Stellar Object Variability (YSOVAR): Long Timescale Variations in the Mid-Infrared
• Identification of Young Stellar Object candidates in the $Gaia$ DR2 x AllWISE catalogue with machine learning methods
• Observations of Solids in Protoplanetary Disks
• Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks
• Constraining the Rate of Protostellar Accretion Outbursts in the Orion Molecular Clouds
• Variability and dust filtration in the transition disk J160421.7-213028 observed in optical scattered light
• Periodic and Aperoidic Variability in the Molecular Cloud ρOphiuchus
• YSOVAR: Mid-IR variability in the star forming region Lynds 1688
• Near-Infrared Variability in the Orion Nebula Cluster
• Near-infrared Variability among YSOs in the Star Formation Region Cygnus OB7
• Spitzer Observations of Long Term Infrared Variability Among Young Stellar Objects in Chamaeleon I
• A "Rosetta Stone" for protoplanetary disks: The synergy of multi-wavelength observations
• YSOVAR: mid-infrared variability of young stellar objects and their disks in the cluster IRAS 20050+2720
• Connecting X-ray and Infrared Variability among Young Stellar Objects: Ruling out potential sources of disk fluctuations
• YSOVAR: Mid-infrared Variability Among YSOs in the Star Formation Region GGD 12-15
• The dipper light curve of V715 Per: is there dust in the magnetosphere?
• Time-monitoring Observations of Br$\gamma$ Emission from Young Stars
• The SPHEREx Target List of Ice Sources (SPLICES)
• The young low-mass star ISO-Oph-50: Extreme variability induced by a clumpy, evolving circumstellar disk
• Dynamics of magnetic flux tubes in accretion discs of T Tauri stars
• The extraordinary far-infrared variation of a protostar: Herschel/PACS observations of LRLL54361
• Fast Photometric Variability of Very Low Mass Stars in IC 348: Detection of Superflare in an M-dwarf
• Variability of Ha emission in young stellar objects in the cluster IC 348
• Statistical Analysis of stars with Ha emission in IC 348 Cluster
• On The Unusual Variability of 2MASS J06195260-2903592: A Long-Lived Disk around a Young Ultracool Dwarf