On the magnetic field properties of protostellar envelopes in Orion

Abstract

We present 870 um polarimetric observations toward 61 protostars in the Orion molecular clouds, with ~400 au (1") resolution using the Atacama Large Millimeter/submillimeter Array. We successfully detect dust polarization and outflow emission in 56 protostars, in 16 of them the polarization is likely produced by self-scattering. Self-scattering signatures are seen in several Class 0 sources, suggesting that grain growth appears to be significant in disks at earlier protostellar phases. For the rest of the protostars, the dust polarization traces the magnetic field, whose morphology can be approximately classified into three categories: standard-hourglass, rotated-hourglass (with its axis perpendicular to outflow), and spiral-like morphology. 40.0% (+-3.0%) of the protostars exhibit a mean magnetic field direction approximately perpendicular to the outflow on several 100--1000 au scales. However, in the remaining sample, this relative orientation appears to be random, probably due to the complex set of morphologies observed. Furthermore, we classify the protostars into three types based on the C17O (3--2) velocity envelope's gradient: perpendicular to outflow, non-perpendicular to outflow, and unresolved gradient (<1.0~km/s/arcsec). In protostars with a velocity gradient perpendicular to outflow, the magnetic field lines are preferentially perpendicular to outflow, most of them exhibit a rotated hourglass morphology, suggesting that the magnetic field has been overwhelmed by gravity and angular momentum. Spiral-like magnetic fields are associated with envelopes having large velocity gradients, indicating that the rotation motions are strong enough to twist the field lines. All of the protostars with a standard-hourglass field morphology show no significant velocity gradient due to the strong magnetic braking.

12 pages, 5 figures (16 pages and 7 figures for the supplementary materials) Accepted for publication on ApJ Letters

References in corpus (29)

• CASA, the Common Astronomy Software Applications for Radio Astronomy
• Magnetic Fields in the Formation of Sun-Like Stars
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. A Statistical Characterization of Class 0 and I Protostellar Disks
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Magnetic Fields and Massive Star Formation
• Placing Confidence Limits on Polarization Measurements
• A protostellar system fed by a streamer of 10,500 au length
• Magnetic Fields and Rotations of Protostars
• Gravitational collapse of magnetized clouds. I. Ideal MHD accretion flow
• The evidence of radio polarization induced by the radiative grain alignment and self-scattering of dust grains in a protoplanetary disk
• ALMA Reveals Transition of Polarization Pattern with Wavelength in HL Tau's Disk
• Magnetically self-regulated formation of early protoplanetary discs
• Interferometric observations of magnetic fields in forming stars
• Gravity Driven Magnetic Field at ~1000 au Scales in High-mass Star Formation
• The Role of Magnetic Fields in Protostellar Outflows and Star Formation
• Submillimeter Array Observations of Magnetic Fields in G240.31+0.07: an Hourglass in a Massive Cluster-forming Core
• Alignment Between Protostellar Outflows and Filamentary Structure
• A case of simultaneous star and planet formation
• Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422
• A statistical analysis of dust polarization properties in ALMA observations of Class 0 protostellar cores
• Misalignment of Magnetic Fields, Outflows and Discs in Star-forming Clouds
• Magnetic Fields in Massive Star-Forming Regions (MagMaR) II. Tomography Through Dust and Molecular Line Polarization in NGC 6334I(N)
• Origin of Misalignments: Protostellar Jet, Outflow, Circumstellar Disc, and Magnetic Field
• Hall Effect in Protostellar Disc Formation and Evolution
• 300: An ACA 870 $\mu$m Continuum Survey of Orion Protostars and their Evolution
• An observational correlation between magnetic field, angular momentum and fragmentation in the envelopes of Class 0 protostars?
• Magnetic Field Structure in Spheroidal Star-Forming Clouds. II. Estimating Field Structure from Observed Maps
• Outflows, cores and magnetic field orientations in W43-MM1 as seen by ALMA
• Magnetic Spirals in Accretion Flows Originated from Misaligned Magnetic Field

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