Aims: We aim to study the rotating and expanding gas in the Red Rectangle, which is a well known bipolar nebula surrounding a double stellar system whose primary is a post-asymptotic giant branch (post-AGB) star.

Hubble discovered that supermassive black holes lurk at the hearts of most galaxies. But not all black holes are equal.

The results of the study were published in The Astrophysical Journal on December 1. Type I X-ray bursts are intense and recurring thermonuclear explosions seen throughout the galaxy.