{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Summary Chapter 11 Star form

Summary Chapter 11 Star form - a supernova explosion b...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter Summaries Chapter 11: The Formation of Stars Short review of Ch 10 ( ISM) Molecular Clouds consist of gas and dust (note: molecules form in molecular clouds) ISM in the Milky Way: 70% H, 28% He, 2% heavy elements Temperature in molecular clouds: 10 – 30 K Molecular clouds are observed in the radio part of the electromagnetic spectrum CO (carbon monoxide) is the main molecule observed Interstellar dust (made of Carbon, Oxygen, Silicon, and Iron) Dust is observed in the Infrared part of the electromagnetic spectrum Interstellar Reddening dust grains block out shorter wavelengths (bluer photons) dust grains emit longer wavelengths (redder photons) -------- Stars form in molecular clouds in the Interstellar Medium (ISM) (Molecular cloud must be very dense to create a single star) 1) dark cloud cores 2) gravitational collapse 3) protostar stage (planet formation, too) 4) main sequence star Star formation is triggered by shocks:
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: a) supernova explosion b) ionization fronts of hot, massive O & B star radiation c) collisions of giant molecular clouds d) spiral arms of galaxies Gravity starts contraction Gravity and thermal pressure (tug of war) Mass of molecular clouds are about 100 solar masses to be able to form stars Magnetic Fields, rotation, and turbulence can prevent or slow a star’s contraction Molecular clouds are a place where stars form in multiples Bok Globules Herbig-Haro Objects T Tauri Stars Protostar Main Sequence Stars (fusion at core balances gravitational force) First Stars: contained only H and He no CO (that would cool collapsing molecular cloud) warmer environment that present epoch of clouds huge stars formed (greater than 30 solar masses) Gravitational Equilibrium (gravity inwards = pressure outwards) Stellar Mass: low limit: 0.08 M Sun upper limit: about 100 M Sun...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern