Outbursting Young Stellar Object PGIR 20dci in the Perseus Arm
Lynne A. Hillenbrand, Kishalay De, Matthew Hankins, Mansi M. Kasliwal, Luisa M. Rebull, Ryan M. Lau, Roc M. Cutri, Michael C. B. Ashley, Viraj R. Karambelkar, Anna M. Moore, T. Travouillon, A. K. Mainzer
Abstract
Abstract We report the discovery of a likely outbursting Class I young stellar object, associated with the star-forming region NGC 281-W (distance ∼2.8 kpc). The source is currently seen only at infrared wavelengths, appearing in both the Palomar Gattini InfraRed (1.2 μ m) and the Near-Earth Object Wide-field Infrared Survey Explorer (3.4 and 4.6 μ 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 He i λ 10830 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.