Evolution of dust and ice features around FU Orionis objects

Abstract

(abridged) We present spectroscopy data for a sample of 14 FUors and 2 TTauri stars observed with the Spitzer Space Telescope or with the Infrared Space Observatory (ISO). Based on the appearance of the 10 micron silicate feature we define 2 categories of FUors. Objects showing the silicate feature in absorption (Category 1) are still embedded in a dusty and icy envelope. The shape of the 10 micron silicate absorption bands is compared to typical dust compositions of the interstellar medium and found to be in general agreement. Only one object (RNO 1B) appears to be too rich in amorphous pyroxene dust, but a superposed emission feature can explain the observed shape. We derive optical depths and extinction values from the silicate band and additional ice bands at 6.0, 6.8 and 15.2 micron. In particular the analysis of the CO_2 ice band at 15.2 micron allows us to search for evidence for ice processing and constrains whether the absorbing material is physically linked to the central object or in the foreground. For objects showing the silicate feature in emission (Category 2), we argue that the emission comes from the surface layer of accretion disks. Analyzing the dust composition reveals that significant grain growth has already taken place within the accretion disks, but no clear indications for crystallization are present. We discuss how these observational results can be explained in the picture of a young, and highly active accretion disk. Finally, a framework is proposed as to how the two categories of FUors can be understood in a general paradigm of the evolution of young, low-mass stars. Only one object (Parsamian 21) shows PAH emission features. Their shapes, however, are often seen toward evolved stars and we question the object's status as a FUor and discuss other possible classifications.

accepted for publication in ApJ; 63 pages preprint style including 8 tables and 24 figures

References in corpus (38)

• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• Interstellar Dust Grains
• The rich 6 to 9 um spectrum of interstellar PAHs
• ISO spectroscopy of circumstellar dust in 14 Herbig Ae/Be systems: towards an understanding of dust processing
• Observational Constraints on the Formation and Evolution of Binary Stars
• The absence of crystalline silicates in the diffuse interstellar medium
• A Survey and Analysis of Spitzer Infrared Spectrograph Spectra of T Tauri Stars in Taurus
• The Burst Mode of Protostellar Accretion
• A 10 micron spectroscopic survey of Herbig Ae star disks: grain growth and crystallization
• ISO spectroscopy of gas and dust: from molecular clouds to protoplanetary disks
• C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth
• ISO spectroscopy of disks around Herbig Ae/Be stars
• Annealing of Silicate Dust by Nebular Shocks at 10 AU
• The Thermal Regulation of Gravitational Instabilities in Protoplanetary Disks III. Simulations with Radiative Cooling and Realistic Opacities
• The unusual hydrocarbon emission from the early carbon star HD 100764: The connection between aromatics and aliphatics
• Ices in the edge-on disk CRBR 2422.8-3423: Spitzer spectroscopy and Monte Carlo radiative transfer modeling
• Spitzer Mid-infrared Spectroscopy of Ices Toward Extincted Background Stars
• Origin of the 6.85 micron band near young stellar objects: The ammonium ion (NH4+) revisited
• Spitzer Space Telescope Spectroscopy of Ices toward Low Mass Embedded Protostars
• Evidence for grain growth in T Tauri disks
• Mid-Infrared Spectroscopy of Disks around Classical T Tauri Stars
• Mid-infrared spectra of PAH emission in Herbig AeBe stars
• Binarity as a key factor in protoplanetary disk evolution: Spitzer disk census of the eta Chamaeleontis cluster
• Spitzer Observations of CO2 Ice Towards Field Stars in the Taurus Molecular Cloud
• 8--13 um spectroscopy of YSOs: Evolution of the silicate feature
• Dust Processing in Disks around T Tauri Stars
• Spitzer-IRS Observations of FU Orionis Objects
• New insights on the AU-scale circumstellar structure of FU Orionis
• The circumstellar envelope of the C-rich post-AGB star HD 56126
• The outburst of the eruptive young star OO Serpentis between 1995 and 2006
• The Outburst of V1647 Ori Revealed by Spitzer
• FU Orionis - The MIDI/VLTI Perspective
• Keck Interferometer Observations of FU Orionis Objects
• First AU-scale observations of V1647 Ori with VLTI/MIDI
• The Unusual X-ray Spectrum of FU Orionis
• The Evolution and Simulation of the Outburst from XZ Tauri - A Possible EXor?
• Deeply embedded objects and shocked molecular hydrogen: The environment of the FU Orionis stars RNO 1B/1C
• The vertical structure of T Tauri accretion discs IV. Self-irradiation of the disc in the FU Orionis outburst phase

Cited by in corpus (56)

• Variable protostellar accretion with episodic bursts
• Resolving the Luminosity Problem in Low-Mass Star Formation
• The formation and evolution of planetary systems: Grain growth and chemical processing of dust in T Tauri systems
• Episodic formation of cometary material in the outburst of a solar-like young star
• Long-term Evolution of Protostellar and Protoplanetary Disks. I. Outbursts
• HOPS 383: An Outbursting Class 0 Protostar in Orion
• Circumstellar Disks of the Most Vigorously Accreting Young Stars
• The 2008 outburst of EX Lup - silicate crystals in motion
• The Long-Lived Disks in the Eta Chamaeleontis Cluster
• EX Lupi in quiescence
• Multiwavelength Observations of V2775 Ori, an Outbursting Protostar in L 1641: Exploring the Edge of the FU Orionis Regime
• Tracing the potential planet-forming regions around seven pre-main-sequence stars
• Near-Infrared High-Resolution Imaging Polarimetry of FU Ori-Type Objects: Towards A Unified Scheme for Low-Mass Protostellar Evolution
• Chemical Signatures of the FU Ori Outbursts
• Long-wavelength excesses of FU Orionis objects: flared outer disks or infalling envelopes?
• Encounter-driven accretion in young stellar clusters - A connection to FUors?
• An Analysis of the Environments of FU Orionis Objects with Herschel
• Knotty protostellar jets as a signature of episodic protostellar accretion?
• Massive compact disks around FU Orionis-type young eruptive stars revealed by ALMA
• A 1.3 mm SMA Survey of 29 Variable Young Stellar Objects
• Mid-infrared spectra of comet nuclei
• A concordant scenario to explain FU Ori from deep centimeter and millimeter interferometric observations
• Evolution of dust in protoplanetary disks of eruptive stars
• Disentangling the Environment of the FU Orionis Candidate HBC 722 with Herschel
• V346 Normae: First post-outburst observations of an FU Orionis star
• Mass transport from the envelope to the disk of V346 Nor: a case study for the luminosity problem in an FUor-type young eruptive star
• The progenitor of the FUor-type young eruptive star 2MASS J06593158-0405277
• Brightness variations of the FUor-type eruptive star V346 Nor
• Dynamics during outburst: VLTI observations of the young eruptive star V1647 Ori during its 2003-2006 outburst
• Interferometric view of the circumstellar envelopes of northern FU Orionis-type stars
• Variability at the Edge: Optical Near/IR Rapid Cadence Monitoring of Newly Outbursting FU Orionis Object HBC 722
• High-resolution polarimetry of Parsamian 21: revealing the structure of an edge-on FU Ori disc
• Spectral evolution and radial dust transport in the prototype young eruptive system EX Lup
• 2MASS J17112318-2724315: A Deeply-Embedded Low-Mass Protostellar System in the B59 Molecular Cloud
• Circumbinary Disks of the Protostellar Binary Systems in the L1551 Region
• Cold CO gas in the envelopes of FU Orionis-type young eruptive stars
• Millimeter interferometric observations of FU Orionis-type objects in Cygnus
• Mid-IR observations of circumstellar disks -- Part III: A mixed sample of PMS stars and Vega-type objects
• Emission from Water Vapor and Absorption from Other Gases at 5-7.5 Microns in Spitzer-IRS Spectra of Protoplanetary Disks
• An ALMA Study of the FU-Ori Type Object V900 Mon: Implications for the Progenitor
• The Mid-Infrared Evolution of the FU Orionis Disk
• Testing the Binary Trigger Hypothesis in FUors
• An APEX study of molecular outflows in FUor-type stars
• Grain growth in newly discovered young eruptive stars
• APEX Observations of the CO Envelope around the Young FUor-type Star V883 Ori
• The Spectroscopic Variations of the FU Orionis Object V960 Mon
• The Brightening of Re50N: Accretion Event or Dust Clearing?
• Infrared spectroscopy of intermediate mass young stellar objects
• Primordial dust rings, hidden dust mass, and the first generation of planetesimals in gravitationally unstable protoplanetary disks
• Accretion Burst Crystallizes Silicates in a Planet-Forming Disk
• Time-domain study of the young massive cluster Westerlund 2 with the Hubble Space Telescope. I
• New Candidate Eruptive Young Stars in Lynds 1340
• The Effelsberg survey of FU Orionis and EX Lupi objects I. -- Host environments of FUors/EXors traced by NH${}_3$
• Near-Infrared Monitoring and Modelling of V1647 Ori in its On-going 2008-12 Outburst Phase
• Semi-analytic calculations for extended mid-Infrared emission associated with FU Ori-type objects
• Episodic accretion in focus: revealing the environment of FU Orionis-type stars