A Faint Progenitor System for the Faint Supernova 2024vjm
Abstract
Type Ia Supernovae (SNe Ia) are well known for their role as standardizable cosmological candles. Their uniformity is credited to their single origin as thermonuclear explosions of White dwarf (WD) stars. Nevertheless, some SNe Ia break this regularity. Prominently, the Iax subclass are less energetic and remarkably diverse, raising questions about their progenitor systems. While no progenitor system of a normal SN Ia has ever been detected, a luminous blue star was identified in pre-explosion images of the site of the bright SN Iax SN 2012Z, suggested to be a helium giant companion star acting as a mass donor to a WD SN progenitor. This is in line with models of weak mass accretion of a WD from a binary companion, producing an explosion that does not fully disrupt the star. However, these models fail to explain the properties of the faintest Type Iax explosions, suggesting either they originate from other WD binary systems, or even from massive progenitor stars. Here, we present the faint SN Iax SN 2024vjm - possibly the faintest supernova observed to date. Using a deep pre-explosion image taken by the recently launched Euclid space mission, we show that its progenitor system must be fainter than the helium giant SN Iax progenitor candidate of SN 2012Z, as well as that of the luminous red companion or remnant of the faint SN 2008ha, and may require a subdwarf helium star as a mass donor. The deep image also provides strong arguments against a massive star origin for this faint supernova. Our observations argue that SN 2024vjm is a WD explosion, but we find that remarkably faint SNe Iax fade more slowly than bright ones, i.e., they evolve in an opposite manner from the famous Phillips relation that makes regular SNe Ia cosmological candles.
Cite
@article{arxiv.2602.09096,
title = {A Faint Progenitor System for the Faint Supernova 2024vjm},
author = {Erez A. Zimmerman and Avishay Gal-Yam and Paul J. Groot and Eran O. Ofek and Jan van Roestel and Andrea Pastorello and Stefano Valenti and Aravind P. Ravi and Ping Chen and Steve Schulze and Nadejda Blagorodnova and Maxime Wavasseur and Marco A. Gomez-Munoz and Hugo Tranin and Simon de Wet and Giorgos Leloudas and Paul M. Vreeswijk and Lindsey A. Kwok and Michaela Schwab and Saurabh W. Jha and Kate Maguire and David J. Sand and Eric Stringer and Thomas Kupfer and Tamar Faran and Joseph P. Anderson and Jennifer Andrews and Moira Andrews and Avshalom Badash and Steven Bloemen and K. Azalee Bostroem and Ting-Wan Chen and Massimo Della Valle and Georgios Dimitriadis and Yize Dong and Joseph R. Farah and James H. Gillanders and Benjamin Godson and Mariusz Gromadzki and Daichi Hiramatsu and Emily Hoang and D. Andrew Howell and Daryl Janzen and Hanindyo Kuncarayakti and Jiaxuan Li and Joseph D. Lyman and Keiichi Maeda and Mark R. Magee and Curtis McCully and Darshana Mehta and Andrew Milligan and Shane Moran and Yuan Qi Ni and David O'Neill and Jeniveve Pearson and Danielle L. A. Pieterse and Giuliano Pignata and Andrea Reguitti and Daniel E. Reichart and Nicolas Meza Retamal and Rita P. Santos and Simone Scaringi and Manisha Shrestha and Shubham Srivastav and Fiorenzo Stoppa and Bhagya Subrayan and Giorgio Valerin and Xiaofeng Wang and Kathryn Wynn and Ofer Yaron and Weicheng Zang},
journal= {arXiv preprint arXiv:2602.09096},
year = {2026}
}