APOD: 2022 December 7 - NGC 7293: The Helix Nebula

Good morning, Rallypoint, and welcome to the December 7th Pearl Harbor Day edition of Astronomy Picture of the Day (APOD): "NGC 7293: The Helix Nebula." The Helix Nebula is a 'planetary nebula' that regularly appears on APOD, and with good reason: due to its proximity to Earth (only 700 light years away).

The term 'planetary nebula' is a bit of a misnomer, in that the nebula is not related to a planet. It is an emission nebula, formed by an expanding, glowing shell of ionized gas ejected from stars late in their lives. These objects resembled planets when viewed through early telescopes...and so the name stuck. In this rendition of NGC 7293, we see the typical red of hydrogen and blue of oxygen. The source of the nebula is the star appearing right in the middle.