JCMT POL-2 and BISTRO Survey Observations of Magnetic Fields in the L1689 Molecular Cloud

We present 850 ?m polarization observations of the L1689 molecular cloud, part nearby Ophiuchus cloud complex, taken with POL-2 polarimeter on James Clerk Maxwell Telescope (JCMT). observe three regions L1689: clump L1689N which houses IRAS 16293-2433 protostellar system, starless SMM-16, and core L1689B. use Davis–Chandrasekhar–Fermi method to estimate plane-of-sky field strengths 366 ± 55 ?G in L1689N, 284 34 72 33 L1689B, for our fiducial value dust opacity. These values indicate that all are likely be magnetically transcritical sub-Alfvénic turbulence. In regions, inferred mean magnetic direction is approximately perpendicular local filament identified Herschel Space observations. The core-scale morphologies L1689B consistent cloud-scale morphology measured by Planck Observatory, suggesting material can flow freely from large small scales these sources. Based measurements, we posit accretion onto may regulated. However, clump-scale nearly seen Planck, it unable efficiently accrete further its surroundings.