A protostellar system fed by a streamer of 10,500 au length

TL;DR

This study reports the first observation of a large-scale streamer connecting a dense core to a young protostellar disk, highlighting the role of environmental inflows in early disk formation.

Contribution

It introduces the discovery of a 10,500 au streamer feeding a protostellar system, emphasizing the significance of large-scale accretion flows in early star and disk formation.

Findings

Detected a large-scale streamer (>10,500 au) connecting core to disk.

Streamer composed of chemically fresh material, indicating recent accretion.

Suggests large-scale inflows influence early disk evolution.

Abstract

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$^{[15,16]}$.