SN 2022erq: A Superluminous Thermonuclear Supernova with Escalating Preexplosion Mass Loss

Zhai, Q, Zhang, J, Wang, X, Pastorello, A, Filippenko, AV, Vinkó, J, Brink, TG, Han, Y, Valerin, G, Rosa, NE, Cai, Y, Lin, W, Yang, Y, Zheng, WK, Meng, X, Wu, C, Li, L, Zhao, Z, Wheeler, JC, Prieto, JL et al (2026) SN 2022erq: A Superluminous Thermonuclear Supernova with Escalating Preexplosion Mass Loss. The Astrophysical Journal, 1007 (2). ISSN 0004-637X

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Abstract

We present a photometric and spectroscopic study of the superluminous Type Ia supernova SN 2022erq. Its early spectra, dominated by iron-group elements with weak intermediate-mass features, might indicate highly efficient nuclear burning, broadly similar to that inferred for some overluminous Type Ia supernovae. The rapid emergence and persistence of narrow Balmer emission lines superposed on this iron-rich spectrum provide clear evidence of long-lived interaction with a hydrogen-rich circumstellar medium (CSM), establishing SN 2022erq as a member of the rare Ia–CSM class. SN 2022erq reached a peak bolometric luminosity of ∼8 × 1043 erg s−1 and exhibited an exceptionally slow postpeak decline, indicating that its light curve is dominated by long duration ejecta–CSM interaction. By combining Hα diagnostics with bolometric light-curve modeling, we reconstruct the preexplosion mass-loss history of the progenitor. The mass-loss rate escalated by 1 order of magnitude over the final decades, rising from ∼0.04 to ∼0.6 M⊙ yr−1. This surge produced a massive, extended CSM shell of ∼3 M⊙ out to ∼3.5 × 1016 cm. The young stellar environment (∼100 Myr) together with this substantial, extensive CSM points to a progenitor system consisting of a white dwarf and an intermediate-mass companion that underwent increasing mass loss prior to explosion.

Item Type:	Article
Uncontrolled Keywords:	5101 Astronomical Sciences; 51 Physical Sciences; 0201 Astronomical and Space Sciences; 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics; 0306 Physical Chemistry (incl. Structural); Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	IOP Publishing
Date of acceptance:	7 July 2026
Date of first compliant Open Access:	24 September 2026
Date Deposited:	24 Sep 2026 09:38
Last Modified:	24 Sep 2026 09:38
DOI or ID number:	10.3847/1538-4357/ae8a46
URI:	https://researchonline.ljmu.ac.uk/id/eprint/29526

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