Submillimeter Observations of the Young Low-Mass Object IRAS 04158+2805

Abstract

We present high spatial resolution Submillimeter Array observations and supplementary single-dish photometry of the molecular gas and dust around IRAS 04158+2805, a young source with spectral type M5-M6 in the Taurus star-forming region. A bright, highly elongated dust structure that extends 8" (~1120 AU) in diameter is revealed in a 883 micron thermal continuum image. This emission geometry is in good agreement with optical observations that show a similar structure in absorption, aligned perpendicular to bipolar scattered light nebulae. However, the interferometric data also clearly demonstrate that the submillimeter continuum emission is not centrally concentrated, but rather appears to have a toroidal geometry with substantially lower intensities inside a radius of ~250-300 AU. Spatially resolved emission from the CO J=3-2 transition exhibits a velocity gradient along the major axis of the dust structure. If this kinematic pattern is interpreted as the signature of rotation around a central object, a relatively low mass is inferred (M_star = 0.3 M_sun, with a ~50% uncertainty). We discuss several possible explanations for the observed gas and dust environment around IRAS 04158+2805, including a flattened envelope with an outflow cavity and a large circumbinary ring. This source offers unique views of the gas and dust environment surrounding a young low-mass stellar system. Its properties are generally not commensurate with formation scenarios for such low-mass objects that rely on dynamical ejection, but rather confirms that a single mechanism - molecular cloud core collapse and fragmentation - can produce stars over a wide range of stellar masses (at least an order of magnitude).

accepted for publication in ApJ; 18 pages, 5 figures

References in corpus (16)

• A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus
• The Evolution of Outflow-Envelope Interactions in Low-Mass Protostars
• The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects II: CO2
• The Disk Around CoKu Tau/4: Circumbinary, not Transitional
• Exploring brown dwarf disks: A 1.3 mm survey in Taurus
• Gas and Dust Emission at the Outer Edge of Protoplanetary Disks
• An Inner Hole in the Disk around TW Hydrae Resolved in 7 Millimeter Dust Emission
• A Survey for New Members of Taurus with the Spitzer Space Telescope
• Spitzer IRS Spectra and Envelope Models of Class I Protostars in Taurus
• A Flattened Protostellar Envelope in Absorption around L1157
• Young, Low-Mass Brown Dwarfs with Mid-Infrared Excesses
• The Spatial Distribution of Brown Dwarfs in Taurus
• Structural and compositional properties of brown dwarf disks: the case of 2MASS J04442713+2512164
• Submillimeter Structure of the Disk of the Butterfly Star
• Multiwavelength studies of the gas and dust disc of IRAS 04158+2805
• Investigating the Nature of Variable Class I and Flat Spectrum Protostars Using 2-4$\mu$m Spectroscopy

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• Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud
• Circumbinary and circumstellar discs around the eccentric binary IRAS 04158+2805 -- a testbed for binary-disc interaction
• The Taurus Boundary of Stellar/Substellar (TBOSS) Survey I: far-IR disk emission measured with Herschel
• Brown dwarf disks with Herschel: Linking far-infrared and (sub)-mm fluxes
• High-resolution Pan-STARRS and SMA observations of IRAS 23077+6707: A giant edge-on protoplanetary disk
• ALMA Reveals an Eccentricity Gradient in the Fomalhaut Debris Disk