Study Guides (238,072)
Canada (114,906)
Astronomy (119)

Astro lecture

3 Pages
Unlock Document

Western University
Astronomy 1021
Stacey Hallman

Astronomy Week 10 – Nov 12   th Lifetimes Illustrated • How much faster than the sun is a 10 solar mass star consuming its fuel? o A: 10,000 times faster • A 10M sun star to the sun has 10 times as much fuel as the Sun Star Clusters • Two types of clusters: o Open clusters: up to several thousands of stars, typically 30 light­years  across. In the galactic plane e.g.: Pleiades o Globular clusters: millions of stars, in the halo of the Galaxy. E.g.: M13 in  Hercules  Clusters • Stars in clusters are about the same age, but not the same mass • HR diagram for these clusters reveals their age As old as it looks • The most massive stars die first, so after typically 10 million years, the most massive stars are less than 10 solar masses • Thus the HR diagram is missing the high-mass stars (because the stars are gone). • And thus, the “turn-off” point determines the age of the cluster! MS Lifetimes • Clusters are the living proof that more massive stars have shorter MS lifetimes. • With mass determining everything about the stars, let’s have a look at what stellar masses typically are, and how many stars have what mass. Stellar Masses on the MS • Lowest mass for MS stars : 0.08 MSun or about 80MJup. This limit is fairly well determined. • Highest mass for MS stars : about 100 Msun. Not so well determined. • Why are there no stars with masses less then 0.08 Msun ? o Not dense enough, cores don’t get hot enough to generate energy • Why are there no stars with masses more tha
More Less

Related notes for Astronomy 1021

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.