The text is a detailed explanation of the universe's largest stars and their characteristics. The smallest star-like objects are brown dwarfs, which are between 13 and 90 times the mass of Jupiter but do not have enough mass to undergo nuclear fusion.
Main sequence stars, which have cores hot and dense enough to ignite hydrogen, are larger and brighter than brown dwarfs. The more mass a star has, the shorter its lifespan. After the hydrogen burning phase ends, stars grow to hundreds of thousands of times their original size.
Red dwarfs, the smallest real stars, are about 100 times the mass of Jupiter and can last up to ten trillion years. The Sun, which is about 7 times more massive than Barnard's Star, has a lifespan of around 10 billion years.
Bigger stars, like Sirius, are 25 times brighter but have a shorter lifespan. The most massive star we know of is R136a1, which is almost 9 million times brighter than the Sun but only 30 times the size of the Sun.
Red Giants, when main sequence stars run out of hydrogen, become giants by swelling their outer layers. Hypergiants, the giant phase of the most massive stars in the universe, have a huge surface area and can radiate a large amount of light.
The largest known stars, possibly the largest possible stars, are red hypergiants. Currently, the star we believe to be among the largest ever found is Stephenson 2-18, which has a diameter 2,150 times the Sun's radius and shines with nearly half a million times the Sun's power.
1. The smallest things with star-like properties are gas giants and brown dwarfs, similar to Jupiter [Document(page_content='00:00:24.31: Like Jupiter, the most massive planet in the solar system.', metadata={})].
2. Brown dwarfs are between 13 and 90 times the mass of Jupiter [Document(page_content='00:00:45.61: They are between 13 and 90 times the mass of Jupiter.', metadata={})].
3. Adding more mass to a brown dwarf makes its interior denser, which increases the pressure in the core enough for nuclear fusion reactions to happen [Document(page_content='00:01:03.30: Interestingly, adding a lot of mass to a brown dwarf doesn\'t make it much bigger, it just makes its interior denser.', metadata={})].
4. Main sequence stars are large balls of gas whose mass exceeds a certain limit, and their cores are hot and dense enough to ignite [Document(page_content='00:01:31.54: Large balls of gas whose mass exceeds a certain limit have their cores hot and dense enough to ignite.', metadata={})].
5. The more mass these stars have, the hotter and brighter they are, and the shorter their lives [Document(page_content='00:01:46.41: The more mass these stars have, the hotter and brighter they are, and the shorter their lives.', metadata={})].
6. Red dwarfs are the smallest real stars and are about 100 times the mass of Jupiter [Document(page_content='00:02:20.18: The smallest real stars are red dwarfs, which are about 100 times the mass of Jupiter,', metadata={})].
7. Red dwarfs are the most abundant type of stars in the universe and can last up to ten trillion years [Document(page_content='00:02:46.83: Because they burn their fuel very slowly, red dwarfs can last up to ten trillion years, a thousand times the current age of the universe.', metadata={})].
8. The Sun dominates the Solar System, representing 99.86% of its entire mass [Document(page_content='00:03:18.37: Because it is much hotter and brighter than red dwarfs, its lifespan is shorter: around 10 billion years. The Sun is 7 times more massive than Barnard\'s Star, and this makes it almost 300 times brighter, with twice the surface temperature.', metadata={})].
9. The brightest star in the night sky, Sirius, is twice the mass of the Sun, with a radius 1.7 times larger, but its surface temperature is almost 10,000° Celsius, making it 25 times brighter [Document(page_content='00:03:43.50: The brightest star in the night sky, Sirius, is twice the mass of the Sun, with a radius 1.7 times larger, but its surface temperature is almost 10,000° Celsius, making it 25 times brighter.', metadata={})].
10. The most massive star we know of is R136a1, which has 315 times the solar mass and is almost 9 million times brighter than the Sun [Document(page_content='00:04:44.78: The most massive star we know of is R136a1. It has 315 times the solar mass and is almost 9 million times brighter than the Sun.', metadata={})].
11. Stars like R136a1 are probably born by the merger of several more massive stars in dense star-forming regions and burn up their hydrogen core in just a few million years [Document(page_content='00:05:36.26: Stars like R136a1 are probably born by the merger of several more massive stars in dense star-forming regions and burn up their hydrogen core in just a few million years.', metadata={})].
12. When main sequence stars run out of hydrogen, their cores contract and become hotter and denser, leading to hotter, faster fusion and causing the outer layers to swell [Document(