";s:4:"text";s:2076:"A planetary nebula is not a planet, although its name often gives that initial impression. A planetary nebula is a nebula that is made up of gas and plasma.They are made by certain types of stars when they die. Originally they were thought to be a region around a star where planets would … Compared with diffuse nebulae (see H II region), planetary nebulae are small objects, having a radius typically of 1 light-year and containing a mass of gas of about 0.3 solar mass. More than one nebula are called nebulae. Forms and structure. One of the largest-known planetary nebulae, the Helix Nebula (NGC 7293) in the constellation Aquarius, subtends an angle of about 20 minutes of arc—two-thirds the angular size of the Moon. We have another type of nebula known as planetary nebula. A planetary nebula forms when a star similar to the size of our Sun runs out of hydrogen fuel in the core and the hydrogen in the outer shell starts fusing. They do not last for very long compared to a star, only tens of thousands of years. Nebula Facts: 11-15. Don’t be deceived by the name. They are named this because they look like planets through small optical telescopes. Planetary Nebula is a misleading name.
Planetary nebulae have nothing to do with planets.