How Stars Work

Learn the basics of how stars work, the different kinds of stars, and why some stars are hotter and brighter than others. For more information, I recommend the following books:
Stellar Evolution and Nucleosynthesis by Ryan and Norton
Stellar Interiors by Hansen, Kawaler, and Trimble
Stars and Stellar Evolution by De Boer and Seggewiss
Stellar Structure and Evolution by Kippenhahn, Weigert, and Weiss
Images from
ESA/Herschel/NASA/JPL-Caltech
NSO, NSF, AURA, Inouye Solar Telescope
Andrea Piacquadio

[@MoempfLP]

This is highly educational. I didn't know there are multiple reactions

[@Paul1_snd.art.s]

This is sooo underated, this is one of the best and well explained videos about stars I've ever watched! You've answered questions I had for so long on topics that no other videos I watched talked about so thank you, you've got a new subscriber!

[@ItsJustAstronomical]

Thank you, I'm so glad!

[@Sifisomabanga]

Why I didnt learn this in school..... Awesome explanation

[@TK-Titanium]

That was well explained. Thank you.

[@chainfrost7851]

I love this channel!!!!

[@WashiAmano]

i love the videos you make so much, thank you very much for your hard work!❤

[@vinniepeterss]

just found your channel, love it mate❤

[@nothingbutlove4886]

Really good and interesting video. You are really good at explaining stuff thoroughly and in a good logical and understandable order. Thank you

[@sandraek9625]

Thanks for sharing!

[@alsy0055]

u actually alive. welcome back

[@ItsJustAstronomical]

Thanks! I finally have more time to devote to this. I should have more of these coming soon.

[@joshygoldiem_j2799]

FUN FACT, In the size comparison between earth, the sun and Betelgeuse, if we take the depicted distance between these objects in the animation to scale, then Betelgeuse is approximately TWICE as far away from the sun as MARS is. Sleep on that tonight😉

[@PolzietTwentyOne]

Wow! That’s pretty interesting!🎉

[@MoempfLP]

Another Question: If hydrogen nuclei are the easiest to fuse because they only have one proton each (6:55), why does it need so much less temperature to fuse hydrogen-2 atoms (10:02) although they have the same amount of protons? (10:06) I assume fusing helium-3 to helium-4 will require a much higher temperature than step 1 because helium-3 has more protons than hydrogen and therefore brown dwarfs also can't do step 3, right?

[@ItsJustAstronomical]

I talk a lot more about this in my other video on the proton-proton chain: kzbin.info/www/bejne/jWnGiWOPl7d_fNE. Just to summarize, the first step is much more difficult to perform because you have to wait for beta decay. Smashing the nuclei together isn't enough, one of the proton has to beta decay while the nuclei are together. For a typical proton in the Sun the first step takes about a billion years. The second step takes about 4 seconds. I think you're right about He-3 to He-4, but I'm having a hard time confirming this. None of my books on the subject directly address this question.

[@AkiDreams]

When will be the release of the How Stars Die video? My little one is waiting for it. Thank you!

[@ItsJustAstronomical]

I think I'll finish it within a week. I've been traveling and distracted by other things. I now finally have time to finish it.

[@MoempfLP]

13:30 Do massive stars also have an outer shell with convection or does the size or the CNO reaction prevent this?

[@ItsJustAstronomical]

Their outer layers are not convective. The outer layers are hot enough that they're still transparent.

[@vinniepeterss]

new subs added❤

[@mdavid1955]

Do CNO fusion stars start out in PPF mode?

[@ItsJustAstronomical]

I assume they would. Stars gradually heat up as they are born. But this period wouldn't last very long.

[@MyMemphisable]

The sun is 100x bigger than the earth, so about 1 x 10^6 earths could fit into the sun. Does that mean a billion suns could fit into the 1000x bigger Betelgeuse?

[@ItsJustAstronomical]

Yes, that's about right

[@poetryflynn3712]

Love me

[@traffictraffic]

2:45 isn't our sun white, or have I been lied to by the internet again?

[@ItsJustAstronomical]

It's a little complicated. In some sense, the sun is white and the other stars are white too because they produce light along the full spectrum. But the sun peaks around the yellow wavelength of light while other stars peak around red or blue.

[@traffictraffic]

@@ItsJustAstronomical ohh okay then

[@satyasankalpapanigrahi9416]

​​@@ItsJustAstronomicalIt's more like a very extremely light shade of yellow color which is extremely near to white in the visible spectrum. So, guess there is not much great difference btw a yellow and white. Both are bright colors. Unlike Red and Blue colors, where you can spot the difference easily. But to spot out a difference between light yellow color and white color. It's bit difficult to computers that is directed thousands of hundreds of kms by a spacecraft which orbits at a nearest langrange point of btw mercury and Sun. I'm talking about solar probes, these are special spacecraft which are made just for studying the sun. Hence the computers which operated the image-color resolution in these getting signals from very vast distance may actually make a bit trouble for us to understand the true color of SUN. ( Probably I guess it's very light yellow color except those regions where sun has dark spots )