SN 2024jlf
© arXiv (2025). DOI: 10.48550/arxiv.2501.18686Multi-band light curve of SN 2024jlf and best fit model light curves.
An international team of astronomers has investigated a newly detected Type II supernova designated SN 2024jlf. The new study, detailed in a paper published Jan. 30 on the arXiv pre-print server, yields important information regarding the evolution of this supernova and the nature of its progenitor.

Type II supernovae (SNe) are the results of rapid collapse and violent explosion of massive stars (with masses above 8.0 solar masses). They are distinguished from other SNe by the presence of hydrogen in their spectra.

Based on the shape of their light curves, they are usually divided into Type IIL and Type IIP. Type IIL SNe show a steady (linear) decline after the explosion, while Type IIP exhibit a period of slower decline (a plateau) that is followed by a normal decay.

SN 2024jlf was first spotted on May 28, 2024 using the Zwicky Transient Facility (ZTF), with a brightness of 15.88 mag. The supernova occurred in NGC 5690 — an edge-on spiral galaxy at a redshift of 0.0058.

Subsequent observations of SN 2024jlf after its discovery have revealed that its spectrum shows a blue continuum with weak flash features, indicating a young core-collapse supernova of Type II. A search for the progenitor of SN 2024jlf has also been conducted. However, no source has been identified in the location of this supernova.

One of the groups of astronomers studying SN 2024jlf was led by Nabeel Rehemtulla of Northwestern University in Evanston, Illinois. Rehemtulla's team employed the BTSbot machine learning model for investigating infant supernovae in the ZTF data.

"The discovery and follow-up of SN 2024jlf demonstrated the efficacy of automating rapid response follow-up of quickly evolving transients. This was done with a new program repurposing the BTSbot model: BTSbot-nearby," the researchers explained.

The study found that the early spectra of SN 2024jlf showcase flash ionization features in hydrogen-alpha, carbon and helium emission lines, which persist for about 1.3-1.8 days.

The photometric data show that SN 2024jlf initially brightened by more than 4.0 mag per day, which is quicker than 90% of Type II SNe in a large ZTF sample. Moreover, SN 2024jlf later appears as a normal Type IIP SN with a plateau phase lasting about 85 days and broad, prominent Balmer P-Cygni features.

According to the authors of the paper, the results suggest that the progenitor of SN 2024jlf was a red supergiant star with a mass of about 10 solar masses. The explosion energy was estimated to be at a level of approximately 1.5 sexdecillion erg, while the mass-loss rate was inferred to be between 0.0001 and 0.001 solar masses per year.

Summing up the findings, the researchers note that their study demonstrates the value of automated follow-up observations of transients for probing the nature of core-collapse supernovae.