Different Types of Stars
One is the main sequence star. Most stars are a main sequence stars, and so the majority of stars are main sequence star so that’s just your normal star. You may not know that the sun is actually a star, it just happens to be very close to Earth so it provides us with heat.
The sun is a main sequence star and then we have red supergiants, that’s another type. A star that you’re familiar with that’s a red supergiant is Betelgeuse. (Which isn’t really spelled like you think Betelgeuse would be spelled, but it has the same pronunciation.)
To give you an idea of how big these types of stars are, I’m going to kind of provide an analogy. Some other types of stars I didn’t get to are the White Dwarf and the Red Dwarf. Right here I have sun, which is an example it’s kind of representing main sequence stars in general.
If the sun were the size of a dime, then Betelgeuse would be about three meters short of being the size of a football field including both end zones. Since it’s only three meters off, we’ll say it’s the size of a football field.
Now, White Dwarf would be the size of a small bacterium, and Red Dwarf would be about the size of a sesame seed. I can kind of just number these in order right here. Football fields obviously the largest, then we go to the dime, then the sesame seed, and then the small bacterium.
You’ve got an idea of the relative size here. A sun and a white dwarf, or excuse me, the sun and the Red Dwarf are somewhat similar in size but the small bacterium is extremely small, and then a football field is extremely huge even compared to a dime.
To kind of attach some actual number of figures to this, the sun is about 1.4 million kilometers in diameter. Then Betelgeuse is about 825 million kilometers in diameter, located about 640 light years from the sun.
In fact if Betelgeuse were located in the same place as the sun it would extend past the orbit of Jupiter. If you think about where the sun is and then you think about the other planets and you know Jupiter is, Betelgeuse would take up all of this area. That’s how large it is, it’s huge really.
Now, the largest known star, which is the hybrid giant VY Canis Majoris, is over three billion kilometers in dynam- diameter. Remember earlier I said the sun is 1.4 kilometers in diameter, well VY Canis Majoris over 3 billion -with a b- kilometers in diameter and is located about 4900 light years from Earth.
Now, most red giants are considerably smaller than Betelgeuse or VY Canis Majoris but are still 25 to 50 times the diameter of the sun. You think about the sun being really huge to provide all that heat to the earth, but really the sun is extremely small when compared to most stars. Or maybe not most stars because main sequence stars are a large kind of star, but the sun is extremely small when we compare it to other stars that are out there.