By Mohan Babu
Nebulae are the diffuse objects that we see in night sky that cannot be resolved as individual stars. Galaxies and star clusters were also called nebulae earlier but not any longer. Emission nebulae is the most common type and it acts as a nursery for star formation with interstellar dust and gases. Planetary nebulae is another type that is named so because it looks like a planet when viewed through a telescope. Planetary nebula is formed when gaseous shells are ejected when the giant stars transform into white dwarf. A supernova remnant is an interesting type of nebula which is an expanding shell of gas left behind after a star has exploded into a supernova.
Cat's eye nebula
Located at a distance of about 3000 light years from Earth in Milky way, Cat's eye nebula is one of the stunning sights in Northern hemisphere. It is a planetary nebula where a dying red giant star ejects ionised gas. Usually a nebula refers to a region where new stars are born. A planetary nebula is different as it marks the end of life of a star.
This is remnant of a supernova that is believed to have occurred in the year 1054. It is located in milky way galaxy at a distance of 6300 light years from Earth. The supernova is rightly named SN 1054 based on the year it occurred. The major credit of recording this event goes to ancient Chinese astronomers.
This is located at distance of about 160,000 light years in the Large Magellanic Cloud, a satellite galaxy of milky way. A supernova was recorded on the outskirts of Tarantula nebula on 1987. This is considered to be the closest Supernova recorded in recent times.
It is a spiral galaxy located at a distance of 2.5 million light years from us. This is the farthest object visible to naked eye in clear viewing conditions. It appears like a cloud to naked eye or when viewed through binoculars. This used to be called the Andromeda nebula earlier. Now, this has been removed from the list of nebula and categorized as a galaxy.