Like any living creatures in this world, star also has birth and death. It has a huge life cycle which may cover billions of years.
Stage 1 - Nebulae - The Dust of Stars
Nebulae are considered as the birth of stars. It consists of clouds of dust and gas from which planets and stars are born. Gases may include Hydrogen and Helium and are cool and spread out compared to gases in stars which are hot and dense. In fact gases in Nebulae are very less dense such that water is considered to be 1,000,000,000,000,000 times denser than the gas in Nebulae.
Nebulae got its name from its shape – like a ring. It is also called star dust because the gases in Nebulae are got from dying stars and it is used in forming new stars.
What makes Nebulae glow? There are 3 types of nebulae depending on its glowing color.
Emission Nebulae: Emission nebulae glow greenish-yellow and red. This is caused by the nearby presence of one or more extremely hot stars. The ultraviolet radiation from the stars causes the hydrogen and oxygen of the nebulae to glow.
Radiation Nebulae: Reflection nebulae glow bluish. They reflect the bluish light emitted by one or more cooler stars in it.
Dark Nebulae: They appear as dark patches due to the absence of nearby stars to light up its gases.
So want to know about the Nebulae nearest to our Planet. Yup, Helix is the Nebulae nearest to earth which is lies about 650 light-years away towards the constellation of Aquarius and spans about 2.5 light-years. Helix Nebula is given a technical designation of NGC 7293. It is created at the end of the life of a Sun-like star.
The above picture is a composite of images released from the ACS instrument on the Hubble Space Telescope and wide-angle images from the Mosaic Camera on the WIYN 0.9-m Telescope at Kitt Peak National Observat.
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