Upcoming space telescopes could reveal 24 dying stars before they explode annually

Astronomers are set to make major progress in understanding the final stages of massive stars. Upcoming space surveys, including Euclid and the Chinese Space Station Telescope (CSST), could dramatically increase the detection of red supergiant (RSG) stars before they explode as supernovae. Currently, only about one such progenitor is found each year—but new research suggests this number may rise to around 24 annually.

The study highlights how Euclid and CSST’s optical and near-infrared filters are particularly well-suited for spotting RSG progenitors. These instruments are expected to detect between 13 and 24 stars per year within a mass range of 8 to 25 times that of the Sun. This surge in detections—an increase by a factor of ten—could finally help solve the long-standing 'RSG problem' in stellar evolution.

The research also clarifies how dust affects observations of these stars. While dust temperature plays a minor role, the optical depth of the dust significantly shapes the observed spectral energy distribution. This insight ensures more accurate mass measurements of progenitors, a key factor in studying their explosive deaths. Euclid, launched in 2023, will release its first major datasets in mid-2026, with Quick Data Release 2 due on 24 June 2026 and Data Release 1 on 21 October 2026. CSST, originally planned for around 2024, has faced delays, but its eventual operation will further boost detection capabilities. Together, these missions will provide the largest-ever sample of directly observed progenitors, offering clearer answers about how massive stars end their lives.

The combined power of Euclid and CSST will transform the study of red supergiant supernovae. With more progenitors identified each year, astronomers can refine models of stellar evolution and the physics behind core collapse. This larger dataset, complete with precise mass measurements, will bring scientists closer to resolving one of astrophysics’ most persistent challenges.