Outbursting Young Stellar Object PGIR 20dci in the Perseus Arm

TL;DR

This paper reports the discovery and analysis of PGIR 20dci, a young stellar object in the Perseus Arm exhibiting FU Ori-like outburst behavior, with detailed infrared observations confirming its nature and documenting its outburst evolution.

Contribution

It presents the first detailed infrared observational study of PGIR 20dci, a rare FU Ori-type outbursting young star with a well-documented two-step brightening.

Findings

Infrared detection of PGIR 20dci in outburst in the Perseus Arm.

Spectroscopic confirmation of FU Ori characteristics, including molecular absorption and wind signatures.

Observation of a two-step brightening process in the mid-infrared.

Abstract

We report the discovery of a likely outbursting Class I young stellar object, associated with the star-forming region NGC 281-W (distance $\sim 2.8$ kpc). The source is currently seen only at infrared wavelengths, appearing in both the Palomar Gattini InfraRed ($1.2~\mu$m) and the Near Earth Object Widefield Infrared Survey Explorer ($3.4$ and $4.6~\mu$m) photometric time-domain surveys. Recent near-infrared imaging reveals a new, extended scattered light nebula. Recent near-infrared spectroscopy confirms the similarity of PGIR 20dci to FU Ori type sources, based on strong molecular absorption in CO, H$_2$O, and OH, weak absorption in several atomic lines, and a warm wind/outflow as indicated by a P Cygni profile in the HeI 10830 A line. This is a rare case of an FU Ori star with a well-measured long term photometric rise before a sharper outburst, and the second instance of an FU Ori star with a documented two-step brightening in the mid-infrared.