Template:POTD/2023-10-11
AG Carinae is a luminous blue variable star in the constellation Carina. It is one of the most luminous stars in the Milky Way, although its great distance from Earth (20,000 light-years) and intervening interstellar dust mean that the star is not usually visible to the naked eye; its apparent brightness varies erratically between magnitude 5.7 and 9.0. Apparently in a transitional phase between a massive class-O blue supergiant and a Wolf–Rayet star, AG Carinae is highly unstable and suffers from erratic pulsations, occasional larger outbursts, and rare massive eruptions. The star is surrounded by a nebula of ejected material at a distance of 0.4 to 1.2 parsecs (1.3 to 3.9 light-years). The nebula contains around 15 solar masses of material, all lost from the star around 10,000 years ago. This photograph of AG Carinae and its surrounding nebula was taken by the Hubble Space Telescope in 2021, as one of its anniversary images.Photograph credit: NASA, ESA and the Space Telescope Science Institute