New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Exam 2 study guide

Star Star Star Star Star
1 review
by: Morgan Owens

Exam 2 study guide astronomy 113

Morgan Owens
GPA 3.5

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

This study guide covers what the teacher said will be on the second exam. Good luck!!
Intro to Astronomy
Study Guide
50 ?




Star Star Star Star Star
1 review
Star Star Star Star Star
"I was sick all last week and these notes were exactly what I needed to get caught up. Cheers!"
Arnulfo Jacobson

Popular in Intro to Astronomy

Popular in Department

This 4 page Study Guide was uploaded by Morgan Owens on Saturday March 19, 2016. The Study Guide belongs to astronomy 113 at George Mason University taught by Pesce in Winter 2016. Since its upload, it has received 429 views.


Reviews for Exam 2 study guide

Star Star Star Star Star

I was sick all last week and these notes were exactly what I needed to get caught up. Cheers!

-Arnulfo Jacobson


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 03/19/16
Astro 113 Exam #2 Review  What details might we observed on the surface of a G­type star? Main sequence G stars have surface temperatures that range from 5250­ 5950 K and 66­150 % of Sol’s luminosity. G­type dwarf stars have between 0.85­1.1 Solar­ masses, which indicates in  theory, that these stars spend 7­15 billion years in the main sequence fusing core hydrogen. They appear yellow. Spicules, sunspots, coronal mass injections, solar flare, plages, filaments.   Compare an O­type main sequence star with a K­type main sequence star. Class O­ very hot and very luminous, most of their radiated output is in the ultraviolet range.  Most rare Class K­ orangish, slightly cooler than the sun. Make up about 12% of main sequence stars,  some are giants and super giants, some are main sequence stars. They have weak hydrogen lines  (if present at all) and neutral metals (Mn I, Fe I, Si I) may be able to be a sun which would lead  to more “Earth” like planets.   What is the Mass­Luminosity relationship for main sequence stars and which are the most  massive? The most luminous stars are the most massive, least luminous are the least massive.  Which main sequence stars are the bluest? O stars  The reddest? M stars *Remembers OBAFGKM What is the approximate surface temperature of a G0 type star? 5,500 K What are the elements and stages of pre­main­sequence stellar evolution? 1. Begins with a cloud of cold gas which contracts under self­gravity(prostar). Potential  energy is transformed into kinetic energy, which then is thermalized so the temperature  goes up.(this phase last a short time) 2. When the cloud is hot enough the gas in ionized and opacity sets in (the gas finds it  harder to lose energy and becomes hotter quicker) 3. The star moves in the HR diagram on the Hayashi­tracks, with constant temperature and  decreasing luminosity. The convective zone recedes from the center and the star moves to higher effective temperatures. Slowly nuclear burning starts at the core 4. Once nuclear burning has set in a star is born and appears on the main sequence.    How are Type 1 Supernovae produced? Type II?  Type I: begins as white dwarf, the mass exceeds Chandrasekhar limit (see below) and it  explodes. Hydrogen emission lines are absent which means there is little or no hydrogen in the  debris from the explosion.  Type II: core collapses, gamma rays tear apart atoms, neutrinos can’t escape pressure, material  falling into core bounces and blasts everything away, high temps and densities in the shock  wave, radioactive decay creates other elements, extremely bright, outshines all other stars in  galaxy for 200 billion years.  Where were the Carbon atoms in your pencil, the Nitrogen and Oxygen atoms you are breathing,  and the Calcium atoms in your bones were all created?  Supernova, and Stardust.  What are the stages of evolution of very massive stars?  1. Hydrogen fusion 2. Helium fusion 3. Carbon fusion 4. Neon fusion 5. Oxygen fusion 6. Silicon fusion 7. Core collapse 8. Explosive supernova What are the end­states of low­mass star evolution?  Low­mass stars consume all the hydrogen into its core, it ignites nuclear reactions that convert  helium to carbon and oxygen. Process of mass ejection strips away stars outer layers and leaves  the core open, allowing it to cool down like a dying ember (white dwarf) Of high­mass star evolution? High­mass stars have high enough temps and pressure to further reactions, carbon fusion  produces oxygen, neon, sodium, and magnesium. Neon fusion furthers oxygen and magnesium  amount. Oxygen fusion produces silicon. Silicon fusion produces a sulfur, iron and nickel. High  mass stars violently blow apart in Type II core­collapse supernova explosions.   What causes the luminosity of a star? The size and matter of stars, the rate of release of energy increases stars luminosity.   What is hydrostatic equilibrium? A balance between the weight of a layer in a star and the pressure that supports it.   Which stars evolve the most rapidly? High­ mass stars. O stars   What condition keeps a white dwarf from collapsing further?  Kept from collapsing by the pressure of its degenerate electrons. Degenerate pressure doesn’t  depend on temp so as the star cools it continues to hold the star together.  What defines a star on the main sequence?  A star that derives its energy from core hydrogen fusion. Luminosity and surface temp place it  on the main sequence of the HR diagram.  Where are elements heavier than Iron created? Supernova.   What is a pulsar? A pulsating radio source that is associated with a rapidly rotating neutron star.   What is a planetary nebula? Luminous shell of gas ejected from an old, low­mass star.   What stellar property determines the final stages of a star’s life?  Mass What is white dwarf?  Low­mass star that is don’t burning its thermonuclear fuel and is a size around the size of earth.  How can we measure a star’s surface temperature?  Color ratio of a star What do stars form from? Cool and dense gas and dust in the ISM.  Where is the energy of a main sequence star produced?  In its core through converting hydrogen to helium  Where does the energy come from? (Thermonuclear fusion)  How can we determine the age of a star cluster?  Presence of lack of luminous blue, high­mass main sequence, without this sequence it shows that the main sequence in the cluster has been “eaten away”.  Type I and II Supernovae are produced in very different sorts of astronomical systems. If I  observe one going off in a distant galaxy, how can I tell whether it is Type I or Type II?  Type II supernovae have hydrogen emission lines, Type I don’t.  What causes a nova? Core collapse of a massive star, or explosion of a white dwarf star.   How do astronomers study prestellar object?  They give off radio waves so they can be detected using detectors that are sensitive to these  electromagnetic radiation.  What is the maximum mass of a white dwarf?  Maximum mass of a white dwarf is called the Chandrasekhar limit, which is equal to 1.4 M What happens if it exceeds the mass limit?  It explodes.  How will the Sun evolve?  From the main sequence the sun will become a red giant, and then have a helium flash, start the  nd 2  red giant phase, increase by size of 100 times, envelop mercury and maybe Venus, then  nuclear reactions will end it will become a white dwarf.  What is the heaviest element that can be produced within the core of a very massive star by  fusion? Iron­ it requires more energy that it produces. 


Buy Material

Are you sure you want to buy this material for

50 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Kyle Maynard Purdue

"When you're taking detailed notes and trying to help everyone else out in the class, it really helps you learn and understand the I made $280 on my first study guide!"

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.