Letter to the Editor

SN 2022jli: The ultraluminous birth of a low-mass X-ray binary

¹ Astronomical Institute Anton Pannekoek, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
² Astrophysics Group, School of Physics & Astronomy, University of Leicester, Leicester LE1 7RH, UK
³ Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
⁴ Institut d’Astrophysique de Paris, CNRS et Sorbonne Université, UMR 7095, 98bis Bd Arago, 75014 Paris, France
e-mail: lasota@iap.fr
⁵ Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, Poland

Received: 18 December 2023
Accepted: 6 February 2024

Abstract

Observations show that the 12.4 d binary system descending from the recent supernova SN 2022jli closely fits hypotheses of how low-mass X-ray binaries form, but requires an apparently super-Eddington accretion luminosity from the accreting component. We show that this agrees very well with the type of accretion-induced beaming found in ultraluminous X-ray sources, as recently strongly confirmed by X-ray polarimetry of the X-ray binary Cyg X-3. Beaming in the SN 2022jli binary system occurs because of the very high mass-transfer rate induced by the violent effect of the supernova on the binary geometry. This explains the very soft nature of the accretion luminosity, its distinctive periodic light curve, and its luminosity decay on a ∼250 day timescale. A test of this picture is that the system’s orbital period should increase on a 10⁵ year timescale.