A 1000 au scale molecular outflow driven by a protostar with an age of <=4000 yr.
FURUYA R.S., KITAMURA Y. and SHINNAGA H.
Abstract (from CDS):
To shed light on the early phase of a low-mass protostar formation process, we conducted interferometric observations toward protostar GF 9-2 using the CARMA and SMA. The observations were carried out in the 12CO J=3-2 line and the continuum emission at wavelengths of 3.3 mm, 1.1 mm, and 850 µm with a spatial resolution of ≃400 au. All of the continuum images detected a single point-like source with a beam-deconvolved effective radius of 250 ± 80 au at the center of the previously known 1.1-4.5 M☉ molecular cloud core. Compact emission is detected toward the object at the Spitzer MIPS and IRAC bands, as well as the four bands at the Wide-field Infrared Survey Explorer. Our spectroscopic imaging of the CO line revealed that the continuum source is driving a 1000 au scale molecular outflow, including a pair of lobes where a collimated "higher"-velocity (∼10 kms–1 with respect to the velocity of the cloud) red lobe exists inside a poorly collimated "lower"-velocity (∼5 kms–1) red lobe. These lobes are rather young (dynamical timescales of ∼500-2000 yr) and the least powerful (momentum rates of ∼10–8–10–6M☉kms–1 yr–1 ) ones so far detected. A protostellar mass of M*≲0.06M☉ was estimated using an upper limit of the protostellar age of τ* <= (4 ± 1) x 103 yr and an inferred nonspherical steady mass accretion rate of ∼1 x 10–5 M☉ yr–1. Together with the results from an SED analysis, we discuss that the outflow system is driven by a protostar with a surface temperature of ∼3000 K, and that the natal cloud core is being dispersed by the outflow.