Class Notes (836,562)
Canada (509,854)
Physics (324)
PHYS 183 (78)
Tracy Webb (34)
Lecture

Lecture 26

2 Pages
139 Views
Unlock Document

Department
Physics
Course
PHYS 183
Professor
Tracy Webb
Semester
Winter

Description
Lecture 26: March 18 , 2013  midterm is non-cumulative covering everything from after the first midterm & up until last Friday’s lecture  final exam will be cumulative  next Monday’s lecture is cancelled  assignment number 3 will be due April 3d  the bizarre stellar graveyard is stellar remnants  white dwarfs & binary systems, neutron stars, black holes  recall: white dwarfs o remnant of low-mass stars o supported by electron degeneracy pressure o upper limit for mass of 1.4 solar masses o gravity wins which collapses the star, but clearly pressure wins again or else it would continue to collapse o as you make them more massive, they get smaller  rearrange matter within them to support the extra mass, which makes them smaller  white dwarfs in binary systems o take low mass star & you let it evolve (burns H & He) & then it loses all outer atmospheres in a planetary nebula  then falls & cools passively essentially forever (only happens if the white dwarf is on its own) o an isolated white dwarf will simply cool & fade forever o 50% of stars are born in binary systems o but a white dwarf in orbit with a companion star suffers a very different fate o important since white dwarfs are extremely small  difficult to study them unless they are in a companion system  binary system stars o mass transfers between close stars o happens often between 2 companion stars o mass from high mass star (red giant) is stolen from the lower mass star which then becomes more massive o what happens as they evolve?  the evolution of the high mass star slows down  the evolution of the low mass star speeds up  will now go through moe massive stellar evolution  WD Novae (distinct from Supernovae) o hydrogen builds up on the surface of the star o the temperature & pressure increases as more mass is accreted o eventually the whole thing will explode o hydrogen ignites rapidly & there is a brief (week-long) burst of fusion o distinct from supernovae since just have the surface of the star exploding
More Less

Related notes for PHYS 183

Log In


OR

Join OneClass

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

Sign up

Join to view


OR

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.


Submit