EPoS Contribution
EPoS Contribution
An ALMA + VLA Survey of Orion Protostars: The Youngest Class 0 Objects

Nicole Karnath
U Toledo, Toledo, OH, US
Using ALMA (continuum at 0.87 mm) and the VLA (Ka-band, 9 mm) data, we present 0.1" resolution images of 24 of the most deeply embedded protostars in the Orion Molecular Cloud. These protostars were selected by their weak or lack of emission at 24 μm from Spitzer but are bright at 70 μm and were first identified by the HOPS (Herschel Orion Protostar Survey) program. Due to their rarity, these deeply embedded protostars have estimated ages < 25,000 yrs. Our data has produced the first images of the dense structures found in the inner envelopes of these protostars and provide a unique glimpse into disk formation, envelope structure, and multiplicity in the early Class 0 phase.
Our images resolve structures down to 40 AU in the inner (<1000 AU) envelopes of our sample. Based on the 870 μm data, we estimate masses in this inner region of 0.01 to 2 Msun. We find a variety of morphologies including three binaries, five disk-like structures, and four cases of irregular, extended emission. The five disk like sources have perpendicular outflow detections, but kinematic confirmation with additional observations are required to fully characterize them. If confirmed, the masses are expected to be more massive than typical proto-planetary disks. The irregular sources show morphologies that appear asymmetric; we discuss possible explanations for these structures. We also compare the VLA and ALMA morphologies to examine the effect of optical depth at 870 μm. Finally, we discuss possible reasons for the different morphologies and whether they represent an early evolutionary sequence.
Caption:
Collaborators:
J.J. Tobin, OU, US
S.T. Megeath, U Toledo, US
Suggested Session: Protostellar disks