THE ROTTEN EGG NEBULA, ANOTHER NEBULA NOT WELL KNOWN THOUGH IT’S NO LESS SPECTACULAR.
Photo By: NASA/ESA Hubble Space Telescope.
The Rotten Egg Nebula (Named because of the vast quantities of sulfur compounds in it, which when combined with other elements, smell like a rotten egg.) is relatively close at only around 5000 light years away and it’s an example of what’s called a proto-planetary nebula or pre-planetary nebula (Not to be confused with proto-planetary or pre planetary DISKS which form solar systems). That means that thousands of years in the future this structure should unfurl into a full blown bipolar planetary nebula.
As usual with planetary nebula it begins with a star that has begun to die. That star as it releases its outer layers of material into the surrounding universe becomes a white dwarf. In this particular case; because of a very dense ring of material surrounding and shrouding the star, the ejected material fires out in opposite directions at nearly one million miles an hour. As it slams into the surrounding material a shock wave of ionized hydrogen and nitrogen (Shown here in blue) forms what looks like a bullet ripping through ballistic gel.
This photo was released by the European Space Agency back in 2001 and at the time it was the first time the then only hypothesized shock structures were observed. They’re unsure of weather the disproportionate shells are a result of different release velocity or if it’s because of the material that it’s colliding into being denser on one side then the other. This object is also called the Calabash Nebula because of its resemblance to well, a calabash.
NAME: OH 231.84+4.22, Rotten Egg Nebula, Calabash Nebula.
WHAT IS IT?: Proto-Planetary Nebula or Pre-Planetary Nebula.
HOW FAR AWAY IS IT?: About 5000 light years.
HOW BIG IS IT?: About 1.4 light years in length.
HOW OLD IS IT?: About 1000 years old as we see it.
APPARENT MAGNITUDE?: About 9.5
WHERE IS IT? (General): Southern constellation Puppis.
WHERE IS IT? (Exact RA/DEC J2000): RA 07h 42m 16.8s / DEC -14° 42′ 52.1″.
SIMBAD Data page for this object: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Rotten+Egg+Nebula
NASA APOD page for this object: http://apod.nasa.gov/apod/ap010903.html