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Forum » SpaceEngine » Science and Astronomy Discussions » Distribution of star types
Distribution of star types
SirSpunkyDate: Wednesday, 21.08.2013, 16:35 | Message # 1
Observer
Group: Newbies
Sweden
Messages: 7
Status: Offline
Hi guys,

I'm trying to figure out how common different types of stars are. The best data I've found so far is this:
http://en.wikipedia.org/wiki....ication

But it only includes main-sequence stars, and seems pretty outdated (its source is from 2001).

Obviously, there are many ways to classify stars, but I'm just looking for any numbers at all.

I read somewhere that 90% of all stars are in their main-sequence phase. Using this number and the table above, I guess I could estimate the number of, say red giants or white dwarfs, but I'm thinking there must be some professional astronomer who've already done this.

How does Space Engine calculate the probability of generating certain star types?
 
WatsisnameDate: Wednesday, 21.08.2013, 22:04 | Message # 2
Galaxy Architect
Group: Global Moderators
United States
Messages: 2611
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That depends -- are you interested in the population of stars in the solar neighborhood, or in star clusters? The distribution within a star cluster will depend on its age, because all the stars formed at the same time. The distribution will also be different for the galactic disk, halo, and core, or in different galaxies.

In general, you could start with the Initial Mass Function to find the probability of a star being of a particular mass and thus spectral type. Then use models for stellar evolution to figure out the fraction of time that a star of particular mass spends on the main sequence before evolving off. StarClock can help there.

Using observations is another way to do it; e.g. check a star catalog or spectroscopic survey.





 
SirSpunkyDate: Wednesday, 21.08.2013, 23:15 | Message # 3
Observer
Group: Newbies
Sweden
Messages: 7
Status: Offline
Thanks a lot! That sounds like a great starting point. Both links are very interesting, especially as I also want to learn more on stellar evolution.

I think I'll limit myself to our solar neighborhood, so calulating statistics from catalogs/databases is definitely another way to go.
 
Forum » SpaceEngine » Science and Astronomy Discussions » Distribution of star types
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