A protostellar system fed by a streamer of 10,500 au length
  Binary formation is an important aspect of star formation. One possible route
for close-in binary formation is disk fragmentation$^{[1,2,3]}$. Recent
observations show small scale asymmetries (<300 au) around young
protostars$^{[2,4]}$, although not always resolving the circumbinary disk, are
linked to disk phenomena$^{[5,6]}$. In later stages, resolved circumbinary disk
observations$^{[7]}$ (<200 au) show similar asymmetries, suggesting the origin
of the asymmetries arises from binary-disk interactions$^{[8,9,10]}$. We
observed one of the youngest systems to study the connection between disk and
dense core. We find for the first time a bright and clear streamer in
chemically fresh material (Carbon-chain species) that originates from outside
the dense core (>10,500 au). This material connects the outer dense core with
the region where asymmetries arise near disk scales. This new structure type,
10x larger than those seen near disk scales, suggests a different
interpretation of previous observations: large-scale accretion flows funnel
material down to disk scales. These results reveal the under-appreciated
importance of the local environment on the formation and evolution of disks in
early systems$^{[13,14]}$ and a possible initial condition for the formation of
annular features in young disks$^{[15,16]}$.
