Identifying the SN 2022acko progenitor with JWST

September 2023 • 2023MNRAS.524.2186V

Authors • Van Dyk, Schuyler D. • Bostroem, K. Azalee • Zheng, WeiKang • Brink, Thomas G. • Fox, Ori D. • Andrews, Jennifer E. • Filippenko, Alexei V. • Dong, Yize • Hoang, Emily • Hosseinzadeh, Griffin • Janzen, Daryl • Jencson, Jacob E. • Lundquist, Michael J. • Meza, Nicolas • Milisavljevic, Dan • Pearson, Jeniveve • Sand, David J. • Shrestha, Manisha • Valenti, Stefano • Howell, D. Andrew

Abstract • We report on analysis using the JWST to identify a candidate progenitor star of the Type II-plateau (II-P) supernova SN 2022acko in the nearby, barred spiral galaxy NGC 1300. To our knowledge, our discovery represents the first time JWST has been used to localize a progenitor system in pre-explosion archival Hubble Space Telescope (HST) images. We astrometrically registered a JWST NIRCam image from 2023 January, in which the SN was serendipitously captured, to pre-SN HST F160W and F814W images from 2017 and 2004, respectively. An object corresponding precisely to the SN position has been isolated with reasonable confidence. That object has a spectral energy distribution (SED) and overall luminosity consistent with a single-star model having an initial mass possibly somewhat less than the canonical 8 M theoretical threshold for core collapse (although masses as high as 9 M for the star are also possible); however, the star's SED and luminosity are inconsistent with that of a super-asymptotic giant branch star that might be a forerunner of an electron-capture SN. The properties of the progenitor alone imply that SN 2022acko is a relatively normal SN II-P, albeit most likely a low-luminosity one. The progenitor candidate should be confirmed with follow-up HST imaging at late times, when the SN has sufficiently faded. This potential use of JWST opens a new era of identifying SN progenitor candidates at high spatial resolution.