The Per-Tau Shell: A Giant Star-Forming Spherical Shell Revealed by 3D Dust Observations

TL;DR

This paper uses high-resolution 3D dust mapping to reveal a giant spherical shell, the Per-Tau Shell, formed by stellar feedback, providing direct 3D observational evidence of feedback-triggered molecular cloud and star formation.

Contribution

It presents the first 3D observational evidence of a feedback-formed shell that triggered molecular cloud formation, based on high-resolution dust maps and auxiliary data.

Findings

Discovery of the 156 pc diameter Per-Tau Shell

Identification of the Tau Ring structure

Support for a feedback-driven formation scenario

Abstract

A major question in the field of star formation is how molecular clouds form out of the diffuse Interstellar Medium (ISM). Recent advances in 3D dust mapping are revolutionizing our view of the structure of the ISM. Using the highest-resolution 3D dust map to date, we explore the structure of a nearby star-forming region, which includes the well-known Perseus and Taurus molecular clouds. We reveal an extended near-spherical shell, 156 pc in diameter, hereafter the "Per-Tau Shell", in which the Perseus and Taurus clouds are embedded. We also find a large ring structure at the location of Taurus, hereafter, the "Tau Ring". We discuss a formation scenario for the Per-Tau Shell, in which previous stellar and supernova (SN) feedback events formed a large expanding shell, where the swept-up ISM has condensed to form both the shell and the Perseus and Taurus molecular clouds within it. We present auxiliary observations of HI, H$\alpha$, $^{26}$Al, and X-rays that further support this scenario, and estimate Per-Tau Shell's age to be $\approx 6-22$ Myrs. The Per-Tau shell offers the first three-dimensional observational view of a phenomenon long-hypothesized theoretically, molecular cloud formation and star formation triggered by previous stellar and SN feedback.