Astr110 Photography Projects, Fall 2005

Bubble Nebula, Stephanie Cutcher

The Bubble Nebula consists of hot, ionized gas that has been ejected outward from the massive star in its center, BD+602522, through stellar wind. It is called an emission nebula, or an ionization nebula. This basically means that it occurs when ultraviolet light from a nearby star shines on hydrogen gas, strips it of its electrons (ionizing it), and causes it to glow. The bubble shape is formed when the gases expand outward in a spherical shell around the star. The Bubble Nebula can be found in the constellation Cassiopeia.

This image of the Bubble Nebula was taken using only a clear filter for improved sensitivity, so we don't see the color of the ionized gas. A color picture would show the hazy gas surrounding the bright star in the middle as red. The gas that makes up the "bubble" is hydrogen gas. Since this image shows the star within the nebula, it is easy to see how the gas has been ejected out from that star. The linear size of the Bubble Nebula is approximately 6.1 light years across.

References:
APOD: 2000 January 18 - NGC 7635: The Bubble Nebula

Hubble Nebulae

Bennett, Jeffrey. The Cosmic Perspective . 3rd ed. San Francisco: Pearson: Addison Wesley, 2004.