O assunto astronômico dessa semana é evolução estelar! Venha saber mais sobre o que acontece com as estrelas nessa #AstroThreadBr ⭐️
This week's astronomical subject is stellar evolution! Join us to know more about what happens with the stars! ✨🌞
By: @astroaline
This week's astronomical subject is stellar evolution! Join us to know more about what happens with the stars! ✨🌞
By: @astroaline
How stars are born?
Stars are born in huge and cold clouds made of gas and dust inside the galaxies, the so-called molecular clouds. As an example, we have the Orion Nebula and the Pillar of Creations Nebula - the one on the picture.
Stars are born in huge and cold clouds made of gas and dust inside the galaxies, the so-called molecular clouds. As an example, we have the Orion Nebula and the Pillar of Creations Nebula - the one on the picture.
Due to its own gravity, the cloud starts to collapse and the matter to gather forming small "piles". Those piles, start to unite, and eventually, the density is so high that the temperature grows in the middle and starts nuclear reactions. It's the beginning of a protostar.
Frequently, some fragments of the piles remain on the protostar formation cloud. This may lead to the formation of double and triple systems. And this is the reason why a huge part of stars in the Universe has a binary companion.
How do stars evolve?
With the collapse of the formation cloud, a hot and dense nuclei is formed, which starts to gather gas and dust. All material will be part of the star, and what's left, will form planets, moons, asteroids, or just keep as dust, spinning around the star.
With the collapse of the formation cloud, a hot and dense nuclei is formed, which starts to gather gas and dust. All material will be part of the star, and what's left, will form planets, moons, asteroids, or just keep as dust, spinning around the star.
Once they're formed, the mass of the star is what will determine their evolution path. So, high mass stars have a different evolution process from low mass stars, and stars with the same mass, usually evolve in the same way.
Stars are classified according to their temperature, from the hottest to the coldest ones on the OBAFGKM sequence (Just remember: Oh Be A Fine Guy, Kiss Me). The blue stars (O) are the hottest achieving temp. of 20.000K. The red (M) ones are the coldest, with temp. of 2.500K.
How stars die?
Low mass stars, at the end of their lives, expel their most external layers forming a Planetary Nebula. This slowly dissipates and, in the end, will leave the stars nuclei in the middle, the so-called White Dwarf.
Low mass stars, at the end of their lives, expel their most external layers forming a Planetary Nebula. This slowly dissipates and, in the end, will leave the stars nuclei in the middle, the so-called White Dwarf.
The high mass stars explode as Supernovas! If their mass is not-that-high, the remainder of the star is a Neutron Star. If the mass is very high, the remainder becomes a stellar Black Hole.
