Overview

• The peer-reviewed study, published in The Astrophysical Journal Letters (DOI: 10.3847/2041-8213/adf62b), compiles and calibrates observations spanning 130 years.
• The central star’s temperature has risen by about 3,000°C since 1893, roughly 1,000°C every 40 years, driving a marked brightening of the nebula’s oxygen green line.
• Researchers report the most prolonged rapid transformation directly tracked in a planetary nebula, yet the heating proceeds more slowly than recent theoretical models predict.
• The star’s current mass is estimated at about 0.57 times the Sun’s, with a progenitor mass of roughly 1.25–1.55 solar masses, informing debates over carbon-production thresholds.
• The dataset blends human-eye measurements with modern spectroscopy and imaging, and places IC 418 about 4,000 light-years away in Lepus.