Disks and Outflows in CO Rovibrational Emission from Embedded, Low-Mass Young Stellar Objects

Abstract

Young circumstellar disks that are still embedded in dense molecular envelopes may differ from their older counterparts, but are historically difficult to study because emission from a disk can be confused with envelope or outflow emission. CO fundamental emission is a potentially powerful probe of the disk/wind structure within a few AU of young protostars. In this paper, we present high spectral (R=90,000) and spatial (0.3") resolution VLT/CRIRES M-band spectra of 18 low-mass young stellar objects (YSOs) with dense envelopes in nearby star-froming regions to explore the utility of CO fundamental 4.6 micron emission as a probe of very young disks. CO fundamental emission is detected from 14 of the YSOs in our sample. The emission line profiles show a range of strengths and shapes, but can generally be classified into a broad, warm component and a narrow, cool component. The broad CO emission is detected more frequently from YSOs with bolometric luminosities of <15 Lsun than those with >15 Lsun, and as with CO emission from CTTSs is attributed to the warm (~1000 K) inner AU of the disk. The CO emission from objects with high bolometric luminosity is produced in cooler (~320 K), narrow lines in 12CO and in rarer isotopologues. From some objects, the narrow lines are blueshifted by up to ~10 km/s, indicating a slow wind origin. For other sources the lines are located at the systemic velocity of the star and likely arise in the disk. For a few YSOs, spatially-extended CO and H2 S(9) emission is detected up to 2" from the central source and is attributed to interactions between the wind and surrounding molecular material. Warm CO absorption is detected in the wind of six objects with velocities up to 100 km/s, often in discrete velocity components. That the wind is partially molecular where it is launched favors ejection in a disk wind rather than a coronal or chromospheric wind.

26 pages, accepted by A&A

References in corpus (41)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• The Magnetic Fields of Classical T Tauri Stars
• UV excess measures of accretion onto young very low-mass stars and brown dwarfs
• Which jet launching mechanism(s) in TTauri stars?
• Accretion in the Rho-Oph pre-main sequence stars
• A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• The Evolution of Outflow-Envelope Interactions in Low-Mass Protostars
• Photoevaporation of protoplanetary discs I: hydrodynamic models
• Spectro-astrometric imaging of molecular gas within protoplanetary disk gaps
• Probing T Tauri Accretion and Outflow with 1 Micron Spectroscopy
• The Mid-Infrared Extinction Law in the Ophiuchus, Perseus, and Serpens Molecular Clouds
• The structure and dynamics of molecular gas in planet-forming zones: A CRIRES spectro-astrometric survey
• c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe I], and H_2 gas-phase lines
• The Origin and Formation of the Circumstellar Disk
• Characterizing the nature of embedded young stellar objects through silicate, ice and millimeter observations
• Spitzer IRS Spectra and Envelope Models of Class I Protostars in Taurus
• Spatially Resolved Molecular Hydrogen Emission in the Inner 200AU Environments of Classical T Tauri Stars
• Multiple protostellar systems. II. A high resolution near-infrared imaging survey in nearby star-forming regions
• The nature of the Class I population in Ophiuchus as revealed through gas and dust mapping
• Tracing the inner edge of the disk around HD 100546 with Ro-vibrational CO Emission Lines
• Single peaked CO emission line profiles from the inner regions of protoplanetary disks
• The Origins of Fluorescent H2 Emission From T Tauri~Stars
• On the origin of [NeII] 12.81 micron emission from pre-main sequence stars: Disks, jets, and accretion
• SMA observations of young disks: separating envelope, disk, and stellar masses in class I YSOs
• [NeII] emission line profiles from photoevaporative disc winds
• The non-dipolar magnetic fields of accreting T Tauri stars
• Mapping warm molecular hydrogen with Spitzer's Infrared Array Camera (IRAC)
• A deeply embedded young protoplanetary disk around L1489 IRS observed by the submillimeter array
• Deep near-IR variability survey of pre-main-sequence stars in Rho Ophiuchi
• The TEXES Survey For H2 Emission From Protoplanetary Disks
• An outflow origin of the [NeII] emission in the T Tau triplet
• Fundamental Vibrational Transition of CO during the Outburst of EX Lupi in 2008
• Quiescent H2 Emission From Pre-Main Sequence Stars in Chamaeleon I
• A Micro Molecular Bipolar Outflow From HL Tau
• The Inner Envelope and Disk of L1527 Revealed: Gemini L'-band Scattered Light Imaging
• Mid-Infrared Observations of Class I/Flat-Spectrum Systems in Six Nearby Molecular Clouds
• Stellar and Circumstellar Properties of Class I Protostars
• Near-IR Molecular Hydrogen Emission of Protostars: Probing Circumstellar Environments
• Near-Infrared Imaging Polarimetry of Young Stellar Objects in rho-Ophiuchi
• AST/RO 13CO(J=2-1) and 12CO(J=4-3) Mapping of Southern Spitzer c2d Small Clouds and Cores

Cited by in corpus (36)

• Towards a Global Evolutionary Model of Protoplanetary Disks
• Hall-effect Controlled Gas Dynamics in Protoplanetary Disks: II. Full 3D Simulations toward the Outer Disk
• Magneto-thermal Disk Wind from Protoplanetary Disks
• Wind-driven Accretion in Protoplanetary Disks --- II: Radial Dependence and Global Picture
• VLT-CRIRES Survey of Rovibrational CO Emission from Protoplanetary Disks
• Measuring Protoplanetary Disk Accretion with H I Pf-beta
• Misaligned Disks in the Binary Protostar IRS 43
• CORINOS I: JWST/MIRI Spectroscopy and Imaging of a Class 0 protostar IRAS 15398-3359
• Evidence for the start of planet formation in a young circumstellar disk
• Water in star-forming regions with Herschel: highly excited molecular emission from the NGC 1333 IRAS 4B outflow
• An empirical sequence of disk gap opening revealed by rovibrational CO
• The depletion of water during dispersal of planet-forming disk regions
• Outflow forces of low mass embedded objects in Ophiuchus: a quantitative comparison of analysis methods
• Scanning disk rings and winds in CO at 0.01-10 au: a high-resolution $M$-band spectroscopy survey with IRTF-iSHELL
• Far-infrared molecular lines from Low- to High-Mass Star Forming Regions observed with Herschel
• Investigating Protostellar Accretion-Driven Outflows Across the Mass Spectrum: JWST NIRSpec IFU 3-5~$\mu$m Spectral Mapping of Five Young Protostars
• Heterogeneity in ${}^{12}$CO/${}^{13}$CO Ratios Toward Solar-Type Young Stellar Objects
• The kinematics and excitation of infrared water vapor emission from planet-forming disks: results from spectrally-resolved surveys and guidelines for JWST spectra
• Observational evidence for dissociative shocks in the inner 100 AU of low-mass protostars using Herschel-HIFI
• High-Resolution Near Infrared Spectroscopy of HD 100546: II. Analysis of variable rovibrational CO emission lines
• JWST Observations of Young protoStars (JOYS): overview of program and early results
• JWST Peers into the Class I Protostar TMC1A: Atomic Jet and Spatially Resolved Dissociative Shock Region
• Direct Determination of the HF/H2 Abundance Ratio in Interstellar Gas
• JWST Observations of Young protoStars (JOYS). Overview of gaseous molecular emission and absorption in low-mass protostars
• Missing water in Class I protostellar disks
• Evolution of CO lines in time-dependent models of protostellar disk formation
• The Identification of 93 Day Periodic Photometric Variability for YSO YLW 16A
• HST FUV imaging of DG Tau: Fluorescent molecular hydrogen emission from the wide angle outflow
• Resolved molecular line observations reveal an inherited molecular layer in the young disk around TMC1A
• Dissecting the different components of the modest accretion bursts of the very young protostar HOPS 373
• IGRINS spectroscopy of Class I sources: IRAS 03445+3242 and IRAS 04239+2436
• Revealing a main-sequence star that consumed a planet with JWST
• Velocity-resolved hot water emission detected toward HL Tau with the Submillimeter Array
• Spectroastrometric Study of Ro-vibrational CO Emission from the Herbig Ae star HD~179218 with iSHELL on the NASA Infrared Telescope Facility
• Ices in the Galactic Centre : solid ice and gaseous CO in the central parsec
• Evidence of Accretion Burst: The Viscously Heated Inner Disk of the Embedded Protostar IRAS 16316-1540