Calabash Nebula

The Calabash Nebula, also known as the Rotten Egg Nebula or by its technical name OH 231.84 +4.22, is a protoplanetary nebula (PPN) 1.4 light years (13 Pm) long and located some 5,000 light years (47 Em) from Earth in the constellation Puppis. The name "Calabash Nebula" was first proposed in 1989 in an early paper on the expected nebular dynamics, based on the nebula's appearance  The Calabash is an almost certain member of the open cluster Messier 46, as it has the same distance, radial velocity, and proper motion. The central star is QX Puppis, a binary composed of a very cool mira variable and an A-type main sequence star.
== Description ==
Violent gas collisions that produced supersonic shock fronts in a dying star are seen in a detailed image from NASA's Hubble Space Telescope.
The object is sometimes called the Rotten Egg Nebula as it contains a relatively large amount of sulphur. The densest parts of the nebula are composed of material ejected recently by the central star and accelerated in opposite directions. This material, shown as yellow in the image, is zooming away at speeds up to one and a half million kilometers per hour (one million miles per hour). Most of the star's original mass is now contained in these bipolar gas structures.
This new Hubble image used filters that only let through light from ionized hydrogen and nitrogen atoms. Astronomers were able to distinguish the warmest parts of the gas heated by the violent shocks and found that they form a complex double-bubble shape. The bright yellow-orange colors in the picture show how dense, high-speed gas is flowing from the star, like supersonic speeding bullets ripping through a medium in opposite directions. The central star itself is hidden in the dusty band at the center.
Much of the gas flow observed today seems to stem from a sudden acceleration that took place about 800 years ago. Astronomers believe that 1,000 years from now, the Calabash Nebula will become a fully developed planetary nebula.
Category:Nebulae
Category:Protoplanetary nebula