An international team of astronomers has recently published a study examining SN 2024jlf, a newly detected Type II supernova (SN) that was first spotted on May 28, 2024. Detailed in a paper released on January 30, 2025, on the arXiv pre-print server, the study provides new insights into the evolution of SN 2024jlf and the nature of its progenitor star. This discovery is significant as it enhances our understanding of the physical processes involved in core-collapse supernovae and helps illuminate the characteristics of the progenitors of these cosmic explosions.
Type II Supernovae: A Quick Overview
Type II supernovae are among the most energetic and spectacular events in the universe. These explosions occur when massive stars (typically greater than 8.0 solar masses) undergo rapid collapse at the end of their lifetimes. The process involves the implosion of a star’s core, leading to a violent explosion that ejects its outer layers into space. Type II supernovae are distinct because they contain hydrogen in their spectra, which is a key feature used to classify them.
Type II supernovae are further divided into Type IIL and Type IIP, based on the shape of their light curves. Type IIL supernovae exhibit a linear decline in brightness after the initial explosion, while Type IIP supernovae show a plateau phase, where the brightness remains relatively stable for an extended period before declining in a more typical fashion.
Discovery of SN 2024jlf
SN 2024jlf was discovered through observations made by the Zwicky Transient Facility (ZTF) on May 28, 2024. At the time of its detection, the supernova had a brightness of 15.88 magnitude. The supernova occurred in NGC 5690, an edge-on spiral galaxy located at a redshift of 0.0058, which is approximately 60 million light-years away from Earth. This proximity made SN 2024jlf an excellent candidate for detailed observation.
The initial spectrum of SN 2024jlf revealed several important characteristics. It displayed a blue continuum with weak flash features, which indicated that the supernova was a young core-collapse supernova of Type II. These early observations also revealed that SN 2024jlf’s light curve exhibited characteristics that set it apart from other Type II supernovae, offering astronomers the chance to learn more about its progenitor star and the explosion itself.
Automated Follow-Up: BTSbot Machine Learning Model
The study, led by Nabeel Rehemtulla from Northwestern University, employed innovative techniques to enhance the efficiency of supernova follow-up observations. The team used a new program based on the BTSbot machine learning model designed to automate the rapid response follow-up of evolving transients, such as supernovae, in the ZTF data. The program, called BTSbot-nearby, was developed to investigate nearby supernovae and quickly analyze their light curves and spectra.
This approach proved to be highly effective in studying the quickly evolving nature of SN 2024jlf. The team was able to observe the supernova’s behavior in near real-time and collect detailed data to investigate its characteristics and evolution.
Spectral Features and Photometric Data
The study’s findings revealed important features in the spectra and photometric data of SN 2024jlf. The early spectra exhibited distinct flash ionization features in the hydrogen-alpha, carbon, and helium emission lines. These features lasted for a period of about 1.3 to 1.8 days, a relatively short duration that provided valuable insights into the nature of the explosion.
The photometric data from the supernova showed that SN 2024jlf initially brightened by more than 4.0 magnitudes per day, which is significantly faster than 90% of other Type II supernovae in a large sample of data from the ZTF. This rapid increase in brightness highlights the dynamic nature of the explosion and provides crucial information about the mechanisms driving the event.
As time progressed, the supernova’s light curve evolved to resemble that of a more typical Type IIP supernova, characterized by a plateau phase lasting approximately 85 days. During this phase, the supernova exhibited broad, prominent Balmer P-Cygni features, a hallmark of Type IIP events. These features further reinforced the classification of SN 2024jlf as a Type II supernova.
Progenitor and Explosion Energy
The study’s authors also sought to determine the characteristics of the progenitor star that led to the explosion of SN 2024jlf. Based on the observed data, they concluded that the progenitor was likely a red supergiant star with an estimated mass of approximately 10 solar masses. This estimate is consistent with other Type II supernovae, which typically result from the death of stars in this mass range.
The explosion energy of SN 2024jlf was estimated to be around 1.5 sexdecillion erg, which is an immense amount of energy released in a short period. In addition, the progenitor star’s mass-loss rate was inferred to be between 0.0001 and 0.001 solar masses per year, suggesting that the star had shed a significant portion of its outer layers prior to the explosion.
Significance of the Study
This new study contributes valuable information to the growing body of research on core-collapse supernovae, particularly in terms of the evolution of Type II supernovae and the properties of their progenitor stars. The use of automated follow-up observations, like the BTSbot-nearby program, is an important step forward in the field, enabling astronomers to rapidly investigate transient events and gain more insights into their nature.
The study of SN 2024jlf is especially significant because it sheds light on the detailed processes that occur during the explosion of a massive star and provides further evidence for the importance of red supergiants as progenitors of Type II supernovae. The information gained from this event can help refine models of supernova evolution and may contribute to a deeper understanding of the end stages of stellar life.
Conclusion
The investigation of SN 2024jlf provides important new insights into the nature of Type II supernovae and the stars that give rise to them. By combining rapid follow-up observations with cutting-edge machine learning tools, astronomers were able to gather detailed data on the supernova’s spectrum, light curve, and progenitor star. This work enhances our understanding of the processes behind these cosmic explosions and underscores the importance of automating the observation of transient events to gain timely insights.
As the study of core-collapse supernovae continues to evolve, the discovery of SN 2024jlf represents an exciting step forward in unraveling the mysteries of stellar evolution and the explosive end of massive stars.
Reference: Nabeel Rehemtulla et al, The BTSbot-nearby discovery of SN 2024jlf: rapid, autonomous follow-up probes interaction in an 18.5 Mpc Type IIP supernova, arXiv (2025). DOI: 10.48550/arxiv.2501.18686