Abstract
We have obtained ALMA Band 7 observations of the FU Ori outburst system at
0.6"x0.5" resolution to measure the link between the inner disk instability and
the outer disk through sub-mm continuum and molecular line observations. Our
observations detect continuum emission which can be well modeled by two
unresolved sources located at the position of each binary component. The
interferometric observations recover the entire flux reported in previous
single-dish studies, ruling out the presence of a large envelope. Assuming that
the dust is optically thin, we derive disk dust masses of \$2\times
10^-4\$M\$\_ødot\$ and \$810^-5\$M\$\_ødot\$, for the north and south
components respectively. We place limits on the disks' radii of \$r<\$45 AU. We
report the detection of molecular emission from \$^12\$CO(3-2), HCO\$^+\$(4-3)
and from HCN(4-3). The \$^12\$CO appears widespread across the two binary
components, and is slightly more extended than the continuum emission. The
denser gas tracer HCO\$^+\$ peaks close to the position of the southern binary
component, while HCN appears peaked at the position of the northern component.
This suggests that the southern binary component is embedded in denser
molecular material, consistent with previous studies that indicate a heavily
reddened object. At this angular resolution any interaction between the two
unresolved disk components cannot be disentangled. Higher resolution images are
vital to understanding the process of star formation via rapid accretion FU
Ori-type episodes.
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