Two Bipolar Outflows and Magnetic Fields in the Multiple Protostar System L1448 IRS 3

Abstract

We present spectral line observations of CO J=2-->1, 13CO J=1-->0, and C18O J=1-->0 and polarimetric observations in the λ=1.3 mm continuum and in CO J=2-->1 toward the multiple protostar system L1448 IRS 3, using the BIMA array. In the λ=1.3 mm continuum, two sources (IRS 3A and 3B) were clearly detected with estimated envelope masses of 0.21 and 1.15 Msolar, and one source (IRS 3C) was marginally detected with an upper mass limit of 0.03 Msolar. In CO J=2-->1, we revealed two outflows originating from IRS 3A and 3B. The masses, mean number densities, momentums, and kinetic energies of outflow lobes were estimated. Based on those estimates and outflow features, we conclude that the two outflows are interacting and that the IRS 3A outflow is nearly perpendicular to the line of sight. In addition, we estimate the velocity, inclination, and opening of the IRS 3B outflow using Bayesian statistics. Linear polarization was detected in both the λ=1.3 mm continuum and CO J=2-->1. The linear polarization in the continuum shows a magnetic field at the central source (IRS 3B) perpendicular to the outflow direction, and the linear polarization in the CO J=2-->1 was detected in the outflow regions either parallel or perpendicular to the outflow direction. Moreover, we comprehensively discuss whether the binary system of IRS 3A and 3B is gravitationally bound, based on the velocity differences detected in 13CO J=1-->0 and C18O J=1-->0 observations and on the outflow features. The specific angular momentum of the system is estimated as ~3×1020 cm2 s-1, comparable to the values obtained from previous studies of binary stars and molecular cloud cores.