Chi

Its story

Chi Aquarii is an aged red giant whose variability was announced by Stebbins and Huffer in 1928. It pulses in three overlapping periods — 32, 38 and 45 days — like a stringed instrument tuned to different scales at once. At 613 light-years in the Water Bearer, it has swollen to 142 times the Sun's radius and now shines two thousand five hundred times brighter than the Sun, before continuing its slow decline toward the end.