A gorgeous new image of a nebular 500 light-years away gives a peek into the process of star formation.
This image from the Dark Energy Camera shows both the dark cloud of Lupus 3 and the shining bright young stars of the nebula Bernes 149. The dark cloud here is essential to the star formation process, as it is a collection of gas and dust which provides the building blocks for new stars to be born. Known as a dark nebula because of its density, Lupus 3 obscures the light of the stars behind it, giving the impression of a swath of black across the starry sky.
The other type of nebula shown here, Bernes 149, is a type called a reflection nebula. This is also a cloud of dust and gas, but less dense than the dark nebula. Instead of blocking out light from stars, this cloud reflects that light, making the cloud appear to glow. Unlike emission nebulae, in which the gas actually glows because it is ionized, the reflection nebula isn’t producing light of its own but is still reflecting enough light to be seen.
Within the nebulae, you can see bright points of light which are young stars. Right in the middle of the image are two close-together stars, HR 5999 and HR 6000, which are blue because of their young age. They are just 1 million years old and aren’t yet big or old enough for nuclear fusion to be occurring in their cores. That means they are not yet main sequence stars, but are instead pre-main-sequence stars that glow because of the strong gravity compressing the matter within them, warming it up.
When stars are born and are young, they give off strong stellar winds which blow away dust and gas from around them. That prevents more stars from being born nearby, which creates an equilibrium to keep the number of new stars being born in balance. Studying sites of star formation like these nebulae can help astronomers learn more about this process and about the early stages of the stellar life cycle.
