THE HOURGLASS NEBULA This planetary nebula is otherwise known as MyCn18, and is located 8,000 light-years away from Earth in the southern constellation Musca. It was discovered by Annie Jump Cannon and Margaret W. Mayall between 1918 and 1924. The shape of the nebula is thought to be due to the expansion of a fast stellar wind within a slowly expanding cloud; the cloud is believed to be denser near its equator than at its poles. The nebula has exhausted its supply of nuclear fuel and ejected its outer layers; its core is becoming a cooling white dwarf. The image was captured in 1995 using the Hubble Space Telescope. The colours within the rings of the nebula represent the different gases within: nitrogen is red; hydrogen is green; and oxygen is blue. -TEL Image Credit: R. Sahai and J. Trauger (JPL), WFPC2, HST, NASA apod.nasa.gov/apod/ap110807.html
Posted on: Fri, 21 Jun 2013 18:41:27 +0000
Trending Topics
Recently Viewed Topics
© 2015