Testing Magnetic Field Models for the Class 0 Protostar L1527

Abstract

For the Class 0 protostar, L1527, we compare 131 polarization vectors from SCUPOL/JCMT, SHARP/CSO and TADPOL/CARMA observations with the corresponding model polarization vectors of four ideal-MHD, non-turbulent, cloud core collapse models. These four models differ by their initial magnetic fields before collapse; two initially have aligned fields (strong and weak) and two initially have orthogonal fields (strong and weak) with respect to the rotation axis of the L1527 core. Only the initial weak orthogonal field model produces the observed circumstellar disk within L1527. This is a characteristic of nearly all ideal-MHD, non-turbulent, core collapse models. In this paper we test whether this weak orthogonal model also has the best agreement between its magnetic field structure and that inferred from the polarimetry observations of L1527. We found that this is not the case; based on the polarimetry observations the most favored model of the four is the weak aligned model. However, this model does not produce a circumstellar disk, so our result implies that a non-turbulent, ideal-MHD global collapse model probably does not represent the core collapse that has occurred in L1527. Our study also illustrates the importance of using polarization vectors covering a large area of a cloud core to determine the initial magnetic field orientation before collapse; the inner core magnetic field structure can be highly altered by a collapse and so measurements from this region alone can give unreliable estimates of the initial field configuration before collapse.

43 pages, 9 figures, 4 tables. Accepted by the Astrophysical Journal

References in corpus (7)

• Theory of Star Formation
• Tracing Magnetic Fields with Aligned Grains
• Magnetic Fields in Dark Cloud Cores: Arecibo OH Zeeman Observations
• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• Gravitational collapse of magnetized clouds. I. Ideal MHD accretion flow
• Constraining the Envelope Structure of L1527 IRS: Infrared Scattered Light Modeling
• Results of SPARO 2003: Mapping Magnetic Fields in Giant Molecular Clouds

Cited by in corpus (6)

• Global simulations of protoplanetary disks with ohmic resistivity and ambipolar diffusion
• Interferometric observations of magnetic fields in forming stars
• The Magnetic Field in the Class 0 Protostellar Disk of L1527
• An Ordered Magnetic Field in the Protoplanetary Disk of AB Aur Revealed by Mid-Infrared Polarimetry
• JCMT POL-2 and ALMA polarimetric observations of 6000-100 au scales in the protostar B335: linking magnetic field and gas kinematics in observations and MHD simulations
• Mid-Infrared Polarization of Herbig Ae/Be Discs