Sextans A: A Seemingly Square Galaxy
What's bothering local galaxy Sextans A ? A small dwarf irregular galaxy spanning 5 thousand light years across, Sextans A is located only 5 million light-years away. Named for its home constellation of Sextans , the “diamond in the rough” structure relates to an ancient unknown event. 100 million years ago, something mysterious started a new wave of star formation in Sextans A's center . Massive short-lived stars exploded in supernovae that caused more star formation and yet more supernovae, ultimately resulting in an expanding shell . Today, young blue stars highlight areas and shell edges high in current star formation, a shell that from our perspective appears roughly square . In the above picture , a bright orange star in our own Milky Way Galaxy appears superposed in the foreground.