Stellar Scaling Relations and basic observations

Size: px
Start display at page:

Download "Stellar Scaling Relations and basic observations"

Transcription

1 Stellar Scaling Relations and basic observations (roughly sections in Choudhuri s book) Astrophysics-I, HS2017 week 3, Oct. 17 & 18, 2017 Benny Trakhtenbrot

2 Stellar structure - recap density mass Hydrostatic equilibrium Radiation generation Radiative transfer (3.1) (3.2) (3.15) (3.16) Convection (3.22)

3 Stellar structure - recap Trivial boundaries: (3.1) (3.2) Rough boundaries: (3.15) (3.16) (3.22) 4 equations with 4 boundary conditions: Is it solvable? Are the solutions unique?

4 Stellar structure - recap Trivial boundaries: (3.1) (3.2) Rough boundaries: (3.15) (3.16) (3.22) 4 equations with 4 boundary conditions: Is it solvable? yes! numerically Are the solutions unique? yes! generally

5 Order-of-Magnitude Estimates Goals: To make drastic simplifying assumptions, in order to derive rough stellar properties of interest Gain insights on relevant physics / improvements

6 The Sun s Central Pressure and Temperature (in Section 3.2.1) We want a (very) rough estimate of these quantities, to understand the physics in play Let s start with the basic (observable) quantities: Equation 3.2 says: Let s plug in some rough/ global values:

7 P P c R r

8 The Sun s Central Pressure and Temperature (in Section 3.2.1) We want a (very) rough estimate of these quantities, to understand the physics in play Let s start with the basic (observable) quantities: Equation 3.2 says: Let s plug in some rough/ global values: So we get: - 6 billion atmospheres! Detailed models give a higher value

9 The Sun s Central Pressure and Temperature (in Section 3.2.1) We already mentioned our assumption of ideal gas: In the center of the sun, the hydrogen-dominated gas is fully ionized, so every atom gives 2 particles: So we get: average density : So we get, which is not too far from detailed models (1.57x )

10 The life-time and fuel source of the Sun (in Section 3.2.2) What drives the luminosity of the sun? Helmholtz (1854) and Kelvin (1861) had a theory: Assume the sun shrinks - R decreases The gravitational energy will decrease: But note that increases When deriving the virial theorem we saw: So the thermal energy increases the star becomes hotter BUT: the thermal energy takes only half of the change in The other half is radiated away and is what we see as L?

11 The life-time and fuel source of the Sun (in Section 3.2.2) The other half is radiated away and is what we see as L? If this is true, then the sun had already radiated away It did so at an energy-loss rate of L So a rough estimate for the age of the sun is: which we call the Kelvin-Helmholtz timescale. Plugging in some numbers: Which results in: - only 10 million years?!

12 Stellar Scaling Relations Goals: To make drastic simplifying assumptions, in order to derive observable relations Test these scaling relations against observations Hopefully, move on

13 Temperature Mass-Size Relation As we already saw, we can linearize the pressure gradient: We can also write a scaling relation for the density: So starting from Eq. 3.2: We obviously get: In an ideal gas the E.o.S. is: Which can be combined to produce:

14 Luminosity Mass Relation Let s (ab)use Eq in a similar way: Using a linear Temperature gradient, and scaling relations: But we already saw above in Eq that: So we can finally write: This is very important, because we observe L from (groups of) stars Imagine 1000 sun-like stars with M and L, and then 10 stars with 10 M. The sun-like stars are ~90% of te mass, but only ~9% of the light! If you have only one 10 M star, it will be 50% of the light and 1% of the mass!

15 Luminosity Mass Relation from Choundhuri s book Notice the units are log10(x), log10(y)

16 Luminosity Temperature Relation The surface of the star is observed to have an effective temperature, T eff and we can assume: We don t specify which temp. Just a generalized property It looks like a blackbody, so we can write: We ve already seen that So we can derive: The massive stars are also hotter and dominate the blue light!

17 Luminosity Temperature Relation Notice the units are log10(x), log10(y)

18 Luminosity Temperature Relation 100 in L

19 Luminosity Temperature Relation

20 Lifetime Mass Relation We can assume that a fraction of the stellar mass is involved in fueling the radiation So the star will exhaust its fuel after a time that scales like: Plugging in the mass-luminosity relation we get: Massive stars shine bright, are hot, and die young!

21 Lifetime Mass Relation

22 Lifetime Mass Relation missing stars from H-R?

23 Lifetime Mass Relation missing stars from H-R?

24 Lifetime Mass Relation

Lecture 5: As Long as the Sun Shines. Temperature of the Sun. Spectrum of the Sun Sunspots. Chromosphere. Sodium. Hydrogen.

Lecture 5: As Long as the Sun Shines. Temperature of the Sun. Spectrum of the Sun Sunspots. Chromosphere. Sodium. Hydrogen. Lecture 5: As Long as the Sun Shines Temperature of the Sun Spectrum of the Sun Sunspots Sodium Hydrogen Magnesium Chromosphere In astronomy, we often see gas glowing in red because of H emission lines.

More information

The Sun. Nearest Star Contains most of the mass of the solar system Source of heat and illumination

The Sun. Nearest Star Contains most of the mass of the solar system Source of heat and illumination The Sun Nearest Star Contains most of the mass of the solar system Source of heat and illumination Outline Properties Structure Solar Cycle Energetics Equation of Stellar Structure TBC Properties of Sun

More information

Astronomy 1 Fall Reminder: When/where does your observing session meet? [See from your TA.]

Astronomy 1 Fall Reminder: When/where does your observing session meet? [See  from your TA.] Astronomy 1 Fall 2016 Reminder: When/where does your observing session meet? [See email from your TA.] Lecture 9, October 25, 2016 Previously on Astro-1 What is the Moon made of? How did the Moon form?

More information

Lifespan on the main sequence. Lecture 9: Post-main sequence evolution of stars. Evolution on the main sequence. Evolution after the main sequence

Lifespan on the main sequence. Lecture 9: Post-main sequence evolution of stars. Evolution on the main sequence. Evolution after the main sequence Lecture 9: Post-main sequence evolution of stars Lifetime on the main sequence Shell burning and the red giant phase Helium burning - the horizontal branch and the asymptotic giant branch The death of

More information

11/19/08. Gravitational equilibrium: The outward push of pressure balances the inward pull of gravity. Weight of upper layers compresses lower layers

11/19/08. Gravitational equilibrium: The outward push of pressure balances the inward pull of gravity. Weight of upper layers compresses lower layers Gravitational equilibrium: The outward push of pressure balances the inward pull of gravity Weight of upper layers compresses lower layers Gravitational equilibrium: Energy provided by fusion maintains

More information

The Sun. The Sun is a star: a shining ball of gas powered by nuclear fusion. Mass of Sun = 2 x g = 330,000 M Earth = 1 M Sun

The Sun. The Sun is a star: a shining ball of gas powered by nuclear fusion. Mass of Sun = 2 x g = 330,000 M Earth = 1 M Sun The Sun The Sun is a star: a shining ball of gas powered by nuclear fusion. Mass of Sun = 2 x 10 33 g = 330,000 M Earth = 1 M Sun Radius of Sun = 7 x 10 5 km = 109 R Earth = 1 R Sun Luminosity of Sun =

More information

Pre Main-Sequence Evolution

Pre Main-Sequence Evolution Stellar Astrophysics: Stellar Evolution Pre Main-Sequence Evolution The free-fall time scale is describing the collapse of the (spherical) cloud to a protostar 1/2 3 π t ff = 32 G ρ With the formation

More information

Lecture 7: Stellar evolution I: Low-mass stars

Lecture 7: Stellar evolution I: Low-mass stars Lecture 7: Stellar evolution I: Low-mass stars Senior Astrophysics 2018-03-21 Senior Astrophysics Lecture 7: Stellar evolution I: Low-mass stars 2018-03-21 1 / 37 Outline 1 Scaling relations 2 Stellar

More information

Low-mass Stellar Evolution

Low-mass Stellar Evolution Low-mass Stellar Evolution The lives of low-mass stars And the lives of massive stars The Structure of the Sun Let s review: The Sun is held together by? The inward force is balanced by? Thinking about

More information

Mass-Luminosity and Stellar Lifetimes WS

Mass-Luminosity and Stellar Lifetimes WS Name Mass-Luminosity and Stellar Lifetimes WS The graph shows the Mass-Luminosity Relationship for main sequence stars. Use it to answer questions 1-3. 1) A star with a mass of 0.5 solar masses would be

More information

Lecture 16: The life of a low-mass star. Astronomy 111 Monday October 23, 2017

Lecture 16: The life of a low-mass star. Astronomy 111 Monday October 23, 2017 Lecture 16: The life of a low-mass star Astronomy 111 Monday October 23, 2017 Reminders Online homework #8 due Monday at 3pm Exam #2: Monday, 6 November 2017 The Main Sequence ASTR111 Lecture 16 Main sequence

More information

What tool do astronomers use to understand the evolution of stars?

What tool do astronomers use to understand the evolution of stars? What tool do astronomers use to understand the evolution of stars? Groups indicate types of stars or stages in their evolution. What is plotted? How does an individual star move around the diagram? What

More information

The life of a low-mass star. Astronomy 111

The life of a low-mass star. Astronomy 111 Lecture 16: The life of a low-mass star Astronomy 111 Main sequence membership For a star to be located on the Main Sequence in the H-R diagram: must fuse Hydrogen into Helium in its core. must be in a

More information

Stars: Their Life and Afterlife

Stars: Their Life and Afterlife The 68 th Compton Lecture Series Stars: Their Life and Afterlife Lecture 3: The Life and Times of Low Mass Stars Brian Humensky, lecturer http://kicp.uchicago.edu/~humensky/comptonlectures.htm October

More information

Astronomy 112: The Physics of Stars. Class 14 Notes: The Main Sequence

Astronomy 112: The Physics of Stars. Class 14 Notes: The Main Sequence Astronomy 112: The Physics of Stars Class 14 Notes: The Main Sequence In the last class we drew a diagram that summarized the basic evolutionary path of stars, as seen from their centers. In this class

More information

Review: HR Diagram. Label A, B, C respectively

Review: HR Diagram. Label A, B, C respectively Stellar Evolution Review: HR Diagram Label A, B, C respectively A C B a) A: White dwarfs, B: Giants, C: Main sequence b) A: Main sequence, B: Giants, C: White dwarfs c) A: Main sequence, B: White Dwarfs,

More information

Astronomy. Stellar Evolution

Astronomy. Stellar Evolution Astronomy A. Dayle Hancock adhancock@wm.edu Small 239 Office hours: MTWR 10-11am Stellar Evolution Main Sequence star changes during nuclear fusion What happens when the fuel runs out Old stars and second

More information

The Sun Closest star to Earth - only star that we can see details on surface - easily studied Assumption: The Sun is a typical star

The Sun Closest star to Earth - only star that we can see details on surface - easily studied Assumption: The Sun is a typical star The Sun Closest star to Earth - only star that we can see details on surface - easily studied Assumption: The Sun is a typical star Why is the Sun hot and bright? Surface Temperature of the Sun: T =

More information

Stellar energy generation on the main sequence

Stellar energy generation on the main sequence Stellar energy generation on the main sequence Once fusion reactions begin at the center of a cloud of gas, we call the object a star. For the bulk of its lifetime, a star fuses hydrogen into helium in

More information

Remember from Stefan-Boltzmann that 4 2 4

Remember from Stefan-Boltzmann that 4 2 4 Lecture 17 Review Most stars lie on the Main sequence of an H&R diagram including the Sun, Sirius, Procyon, Spica, and Proxima Centauri. This figure is a plot of logl versus logt. The main sequence is

More information

10/17/2012. Stellar Evolution. Lecture 14. NGC 7635: The Bubble Nebula (APOD) Prelim Results. Mean = 75.7 Stdev = 14.7

10/17/2012. Stellar Evolution. Lecture 14. NGC 7635: The Bubble Nebula (APOD) Prelim Results. Mean = 75.7 Stdev = 14.7 1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 10/17/2012 Stellar Evolution Lecture 14 NGC 7635: The Bubble Nebula (APOD) Prelim Results 9 8 7 6 5 4 3 2 1 0 Mean = 75.7 Stdev = 14.7 1 Energy

More information

Guiding Questions. Stellar Evolution. Stars Evolve. Interstellar Medium and Nebulae

Guiding Questions. Stellar Evolution. Stars Evolve. Interstellar Medium and Nebulae Guiding Questions Stellar Evolution 1. Why do astronomers think that stars evolve? 2. What kind of matter exists in the spaces between the stars? 3. What steps are involved in forming a star like the Sun?

More information

Announcements. - Homework #5 due today - Review on Monday 3:30 4:15pm in RH103 - Test #2 next Tuesday, Oct 11

Announcements. - Homework #5 due today - Review on Monday 3:30 4:15pm in RH103 - Test #2 next Tuesday, Oct 11 Announcements - Homework #5 due today - Review on Monday 3:30 4:15pm in RH103 - Test #2 next Tuesday, Oct 11 Review for Test #2 Oct 11 Topics: The Solar System and its Formation The Earth and our Moon

More information

Filling the intellectual Vacuum: Energy Production. Contenders: From early 1920s: probably fusion, but how?

Filling the intellectual Vacuum: Energy Production. Contenders: From early 1920s: probably fusion, but how? Life of Stars Filling the intellectual Vacuum: Contenders: Energy Production Gravitational contraction Radioactivity (1903) Annihilation (E=mc 2, 1905) of proton and electron Hydrogen to helium nuclear

More information

Book page cgrahamphysics.com Stellar Spectra

Book page cgrahamphysics.com Stellar Spectra Book page 650-652 Stellar Spectra Emission and absorption Spectra The black lines of the absorption spectrum match up with the bright lines of the emission spectrum Spectra unique to each element Emission

More information

Stars and their properties: (Chapters 11 and 12)

Stars and their properties: (Chapters 11 and 12) Stars and their properties: (Chapters 11 and 12) To classify stars we determine the following properties for stars: 1. Distance : Needed to determine how much energy stars produce and radiate away by using

More information

Astronomy 1102 Exam #1 Chapters 1,2,5,6 & 16

Astronomy 1102 Exam #1 Chapters 1,2,5,6 & 16 Astronomy 1102 Exam #1 Chapters 1,2,5,6 & 16 Chapter 1 Degrees- basic unit of angle measurement, designated by the symbol -a full circle is divided into 360 and a right angle measures 90. arc minutes-one-sixtieth

More information

Life and Death of a Star. Chapters 20 and 21

Life and Death of a Star. Chapters 20 and 21 Life and Death of a Star Chapters 20 and 21 90 % of a stars life Most stars spend most of their lives on the main sequence. A star like the Sun, for example, after spending a few tens of millions of years

More information

Lecture 14: The Sun and energy transport in stars. Astronomy 111

Lecture 14: The Sun and energy transport in stars. Astronomy 111 Lecture 14: The Sun and energy transport in stars Astronomy 111 Energy transport in stars What is a star? What is a star composed of? Why does a star shine? What is the source of a star s energy? Laws

More information

Stellar Models ASTR 2110 Sarazin

Stellar Models ASTR 2110 Sarazin Stellar Models ASTR 2110 Sarazin Jansky Lecture Tuesday, October 24 7 pm Room 101, Nau Hall Bernie Fanaroff Observing the Universe From Africa Trip to Conference Away on conference in the Netherlands

More information

UNIVERSITY OF SOUTHAMPTON

UNIVERSITY OF SOUTHAMPTON UNIVERSITY OF SOUTHAMPTON PHYS3010W1 SEMESTER 2 EXAMINATION 2014-2015 STELLAR EVOLUTION: MODEL ANSWERS Duration: 120 MINS (2 hours) This paper contains 8 questions. Answer all questions in Section A and

More information

Introduction to Astronomy. Lecture 8: The Death of Stars White Dwarfs, Neutron Stars, and Black Holes

Introduction to Astronomy. Lecture 8: The Death of Stars White Dwarfs, Neutron Stars, and Black Holes Introduction to Astronomy Lecture 8: The Death of Stars White Dwarfs, Neutron Stars, and Black Holes Continued from Last Week Lecture 7 Observing Stars Clusters of stars Some clouds start breaking into

More information

Physics 556 Stellar Astrophysics Prof. James Buckley. Lecture 9 Energy Production and Scaling Laws

Physics 556 Stellar Astrophysics Prof. James Buckley. Lecture 9 Energy Production and Scaling Laws Physics 556 Stellar Astrophysics Prof. James Buckley Lecture 9 Energy Production and Scaling Laws Equations of Stellar Structure Hydrostatic Equilibrium : dp Mass Continuity : dm(r) dr (r) dr =4πr 2 ρ(r)

More information

The Sun and Stellar Structure 7/9/09. Astronomy 101

The Sun and Stellar Structure 7/9/09. Astronomy 101 The Sun and Stellar Structure 7/9/09 Astronomy 101 Astronomy Picture of the Day Astronomy 101 Something Cool: The Northern (and Southern) Lights Astronomy 101 Outline for Today Astronomy Picture of the

More information

Convection When the radial flux of energy is carried by radiation, we derived an expression for the temperature gradient: dt dr = - 3

Convection When the radial flux of energy is carried by radiation, we derived an expression for the temperature gradient: dt dr = - 3 Convection When the radial flux of energy is carried by radiation, we derived an expression for the temperature gradient: dt dr = - 3 4ac kr L T 3 4pr 2 Large luminosity and / or a large opacity k implies

More information

Based on the reduction of the intensity of the light from a star with distance. It drops off with the inverse square of the distance.

Based on the reduction of the intensity of the light from a star with distance. It drops off with the inverse square of the distance. 6/28 Based on the reduction of the intensity of the light from a star with distance. It drops off with the inverse square of the distance. Intensity is power per unit area of electromagnetic radiation.

More information

ASTR-1020: Astronomy II Course Lecture Notes Section VI

ASTR-1020: Astronomy II Course Lecture Notes Section VI ASTR-1020: Astronomy II Course Lecture Notes Section VI Dr. Donald G. Luttermoser East Tennessee State University Edition 4.0 Abstract These class notes are designed for use of the instructor and students

More information

Astronomy 104: Second Exam

Astronomy 104: Second Exam Astronomy 104: Second Exam Stephen Lepp October 29, 2014 Each question is worth 2 points. Write your name on this exam and on the scantron. Short Answer A The Sun is powered by converting hydrogen to what?

More information

Lecture 11: The Internal Structure of Stars Reading: Section 18-2

Lecture 11: The Internal Structure of Stars Reading: Section 18-2 Lecture 11: The Internal Structure of Stars Reading: Section 18-2 Key Ideas: Observational Clues to Stellar Structure H-R Diagram Mass-Luminosity Relation Hydrostatic Equilibrium Balance between Gravity

More information

Masses are much harder than distance, luminosity, or temperature. Binary Stars to the Rescue!! AST 101 Introduction to Astronomy: Stars & Galaxies

Masses are much harder than distance, luminosity, or temperature. Binary Stars to the Rescue!! AST 101 Introduction to Astronomy: Stars & Galaxies Last Two Classes Measuring the Stars AST 101 Introduction to Astronomy: Stars & Galaxies 1. Measuring distances 2. Measuring stellar luminosities 3. Measuring temperatures Next 4. Measuring masses Masses

More information

Lecture 12: Making the Sun Shine Readings: Sections 18-1, 18-4 and Box 18-1

Lecture 12: Making the Sun Shine Readings: Sections 18-1, 18-4 and Box 18-1 Lecture 12: Making the Sun Shine Readings: Sections 18-1, 18-4 and Box 18-1 Key Ideas Stars shine because they are hot need an internal energy source to stay hot Kelvin-Helmholtz Mechanism Energy from

More information

The Night Sky. The Universe. The Celestial Sphere. Stars. Chapter 14

The Night Sky. The Universe. The Celestial Sphere. Stars. Chapter 14 The Night Sky The Universe Chapter 14 Homework: All the multiple choice questions in Applying the Concepts and Group A questions in Parallel Exercises. Celestial observation dates to ancient civilizations

More information

Chapter 15 Surveying the Stars. Agenda

Chapter 15 Surveying the Stars. Agenda hapter 15 Surveying the Stars genda nnounce: Test in 2.5 weeks Masteringastronomy.com issues Relativity review Review our sun h. 15 Surveying the Stars Lab Special vs. General Relativity pplies only to

More information

Chapter 14. Stellar Evolution I. The exact sequence of evolutionary stages also depends on the mass of a star.

Chapter 14. Stellar Evolution I. The exact sequence of evolutionary stages also depends on the mass of a star. Chapter 14 Stellar Evolution I I. Introduction Stars evolve in the sense that they pass through different stages of a stellar life cycle that is measured in billions of years. The longer the amount of

More information

Selected Questions from Minute Papers. Outline - March 2, Stellar Properties. Stellar Properties Recap. Stellar properties recap

Selected Questions from Minute Papers. Outline - March 2, Stellar Properties. Stellar Properties Recap. Stellar properties recap Black Holes: Selected Questions from Minute Papers Will all the material in the Milky Way eventually be sucked into the BH at the center? Does the star that gives up mass to a BH eventually get pulled

More information

The Interiors of the Stars

The Interiors of the Stars The Interiors of the Stars Hydrostatic Equilibrium Stellar interiors, to a good first approximation, may be understood using basic physics. The fundamental operating assumption here is that the star is

More information

2. Equations of Stellar Structure

2. Equations of Stellar Structure 2. Equations of Stellar Structure We already discussed that the structure of stars is basically governed by three simple laws, namely hyostatic equilibrium, energy transport and energy generation. In this

More information

Lecture 21 Formation of Stars November 15, 2017

Lecture 21 Formation of Stars November 15, 2017 Lecture 21 Formation of Stars November 15, 2017 1 2 Birth of Stars Stars originally condense out of a COLD, interstellar cloud composed of H and He + trace elements. cloud breaks into clumps (gravity)

More information

The Sun - Size and Mass. Masses. Note: Most of solar system mass is in. Radii } } Densities

The Sun - Size and Mass. Masses. Note: Most of solar system mass is in. Radii } } Densities The Sun - Size and Mass Masses Note: Most of solar system mass is in Radii } } Densities 1 2 3 Sun - Composition Consolmagno & Schaefer 4 5 From Wood, in Beatty & Chaikin 6 The missing elements form gases

More information

Exam #2 Review Sheet. Part #1 Clicker Questions

Exam #2 Review Sheet. Part #1 Clicker Questions Exam #2 Review Sheet Part #1 Clicker Questions 1) The energy of a photon emitted by thermonuclear processes in the core of the Sun takes thousands or even millions of years to emerge from the surface because

More information

Problem Score Worth

Problem Score Worth Exam #3 79205 Astronomy Fall 1997 NAME: Solutions You have two hours to complete this exam. There are a total of six problems and you are to solve all of them. Not all the problems are worth the same number

More information

The structure and evolution of stars. Introduction and recap

The structure and evolution of stars. Introduction and recap The structure and evolution of stars Lecture 3: The equations of stellar structure 1 Introduction and recap For our stars which are isolated, static, and spherically symmetric there are four basic equations

More information

The History and Philosophy of Astronomy

The History and Philosophy of Astronomy Astronomy 350L (Fall 2006) The History and Philosophy of Astronomy (Lecture 17: Birth of Astrophysics II) Instructor: Volker Bromm TA: Jarrett Johnson The University of Texas at Austin Which questions

More information

Astronomy 112: The Physics of Stars. Class 13 Notes: Schematics of the Evolution of Stellar Cores

Astronomy 112: The Physics of Stars. Class 13 Notes: Schematics of the Evolution of Stellar Cores Astronomy 112: The Physics of Stars Class 13 Notes: Schematics of the Evolution of Stellar Cores We re now done with our discussion of physical processes in stars, and we are ready to begin the last phase

More information

Notepack 23 12/19/2014 Stellar Evolution: Aim: The Life Cycle of a Star

Notepack 23 12/19/2014 Stellar Evolution: Aim: The Life Cycle of a Star Notepack 23 12/19/2014 Stellar Evolution: Aim: The Life Cycle of a Star Do Now: Where do stars come from? What are they made of? What is a Star? What is a Star? A star is a massive ball of gas that has

More information

Chapter 15 Surveying the Stars

Chapter 15 Surveying the Stars Chapter 15 Surveying the Stars 15.1 Properties of Stars Our goals for learning How do we measure stellar luminosities? How do we measure stellar temperatures? How do we measure stellar masses? How do we

More information

Chapter 15: Surveying the Stars

Chapter 15: Surveying the Stars Chapter 15 Lecture Chapter 15: Surveying the Stars Surveying the Stars 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How

More information

Today. Stars. Properties (Recap) Binaries. Stellar Lifetimes

Today. Stars. Properties (Recap) Binaries. Stellar Lifetimes Today Stars Properties (Recap) Binaries Stellar Lifetimes 1 Exam Review Session This Tuesday, 6-8 PM, PHYS 1410 (the large lecture hall next to ours) Completely driven by your questions! The TAs will not

More information

Chapter 15 Surveying the Stars Properties of Stars

Chapter 15 Surveying the Stars Properties of Stars Chapter 15 Surveying the Stars 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How do we measure stellar masses? Luminosity:

More information

Ch. 29 The Stars Stellar Evolution

Ch. 29 The Stars Stellar Evolution Ch. 29 The Stars 29.3 Stellar Evolution Basic Structure of Stars Mass effects The more massive a star is, the greater the gravity pressing inward, and the hotter and more dense the star must be inside

More information

AST 101 Intro to Astronomy: Stars & Galaxies

AST 101 Intro to Astronomy: Stars & Galaxies REVIEW FROM LAST CLASS AST 101 Intro to Astronomy: Stars & Galaxies Do we have direct evidence for fusion in the Sun? ANNOUNCEMENTS: First MIDTERM on FRIDAY 02/27 YES! Neutrinos REVIEW FROM LAST CLASS

More information

Lecture 13: The Sun, and how stars work. Astronomy 111 Wednesday October 11, 2017

Lecture 13: The Sun, and how stars work. Astronomy 111 Wednesday October 11, 2017 Lecture 13: The Sun, and how stars work Astronomy 111 Wednesday October 11, 2017 Reminders Star party tomorrow night! Homework #6 due Monday How do stars work? What is a star? What is a star composed of?

More information

Introduction to the Sun

Introduction to the Sun Lecture 15 Introduction to the Sun Jiong Qiu, MSU Physics Department Open Q: what physics do we learn about the Sun? 1. Energy - nuclear energy - magnetic energy 2. Radiation - continuum and line emissions;

More information

AST101 Lecture 13. The Lives of the Stars

AST101 Lecture 13. The Lives of the Stars AST101 Lecture 13 The Lives of the Stars A Tale of Two Forces: Pressure vs Gravity I. The Formation of Stars Stars form in molecular clouds (part of the interstellar medium) Molecular clouds Cold: temperatures

More information

Outline - March 18, H-R Diagram Review. Protostar to Main Sequence Star. Midterm Exam #2 Tuesday, March 23

Outline - March 18, H-R Diagram Review. Protostar to Main Sequence Star. Midterm Exam #2 Tuesday, March 23 Midterm Exam #2 Tuesday, March 23 Outline - March 18, 2010 Closed book Will cover Lecture 8 (Special Relativity) through Lecture 14 (Star Formation) only If a topic is in the book, but was not covered

More information

Stellar Structure. Observationally, we can determine: Can we explain all these observations?

Stellar Structure. Observationally, we can determine: Can we explain all these observations? Stellar Structure Observationally, we can determine: Flux Mass Distance Luminosity Temperature Radius Spectral Type Composition Can we explain all these observations? Stellar Structure Plan: Use our general

More information

ASTR 1120 General Astronomy: Stars & Galaxies

ASTR 1120 General Astronomy: Stars & Galaxies ASTR 1120 General Astronomy: Stars & Galaxies HOMEWORK #3 due NEXT TUE, 09/29, by 5pm Fiske planetarium: The Birth of Stars by Prof. John Bally - TH 09/24-FRI 09/25, 7:30pm Astronomer s s Toolbox: What

More information

7/9. What happens to a star depends almost completely on the mass of the star. Mass Categories: Low-Mass Stars 0.2 solar masses and less

7/9. What happens to a star depends almost completely on the mass of the star. Mass Categories: Low-Mass Stars 0.2 solar masses and less 7/9 What happens to a star depends almost completely on the mass of the star. Mass Categories: Low-Mass Stars 0.2 solar masses and less Medium-Mass Stars 0.2 solar masses up to between 2 and 3 solar masses.

More information

AST1100 Lecture Notes

AST1100 Lecture Notes AST1100 Lecture Notes 20: Stellar evolution: The giant stage 1 Energy transport in stars and the life time on the main sequence How long does the star remain on the main sequence? It will depend on the

More information

Lecture 8: The Death of Stars White Dwarfs, Neutron Stars, and Black Holes

Lecture 8: The Death of Stars White Dwarfs, Neutron Stars, and Black Holes Lecture 8: The Death of Stars White Dwarfs, Neutron Stars, and Black Holes ! the time a star is fusing hydrogen into helium in its core! stars spend most of their time in this stage! main-sequence stars

More information

OPEN CLUSTER PRELAB The first place to look for answers is in the lab script!

OPEN CLUSTER PRELAB The first place to look for answers is in the lab script! NAME: 1. Define using complete sentences: Globular Cluster: OPEN CLUSTER PRELAB The first place to look for answers is in the lab script! Open Cluster: Main Sequence: Turnoff point: Answer the following

More information

Last time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy.

Last time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy. Last time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy. Last time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy. Fusion rate ~ Temperature

More information

Stellar structure and evolution

Stellar structure and evolution Stellar structure and evolution Ulrike Heiter Uppsala University July 2012, Nordic-Baltic Summer School Outline 1. The lives of stars Overview of stellar evolution 2. Physics of stellar evolution Stellar

More information

The Cosmic Perspective. Surveying the Properties of Stars. Surveying the Stars. How do we measure stellar luminosities?

The Cosmic Perspective. Surveying the Properties of Stars. Surveying the Stars. How do we measure stellar luminosities? Surveying the Stars Chapter 15 Lecture The Cosmic Perspective 15.1 Properties of Stars Our goals for learning: How do we measure stellar luminosities? How do we measure stellar temperatures? How do we

More information

Homologous Stellar Models and Polytropes

Homologous Stellar Models and Polytropes Homologous Stellar Models and Polytropes Main Sequence Stars Stellar Evolution Tracks and Hertzsprung-Russell Diagram Star Formation and Pre-Main Sequence Contraction Main Sequence Star Characteristics

More information

The Life of Our Sun The Life of Our Sun

The Life of Our Sun The Life of Our Sun The Life of a Star Chapter 14 Stellar Evolution 1 2 Mass Is the Key Stars require millions to billions of years to evolve a time that is incredibly slow by human standards A star s evolution can be studied

More information

Fundamental Stellar Parameters. Radiative Transfer. Stellar Atmospheres

Fundamental Stellar Parameters. Radiative Transfer. Stellar Atmospheres Fundamental Stellar Parameters Radiative Transfer Stellar Atmospheres Equations of Stellar Structure Basic Principles Equations of Hydrostatic Equilibrium and Mass Conservation Central Pressure, Virial

More information

Review Chapter 10. 2) A parsec is slightly more than 200,000 AU. 2)

Review Chapter 10. 2) A parsec is slightly more than 200,000 AU. 2) Review Chapter 10 TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 1) A parsec is about 3.3 light-years. 1) 2) A parsec is slightly more than 200,000 AU. 2) 3) The nearest

More information

Agenda for Ast 309N, Sep. 27. Measuring Masses from Binary Stars

Agenda for Ast 309N, Sep. 27. Measuring Masses from Binary Stars Agenda for Ast 309N, Sep. 27 Quiz 3 The role of stellar mass Ages of star clusters Exam 1, Thurs. Oct. 4 Study guide out on 9/28 Next topic: brown dwarfs and extrasolar planets 1 This image of the central

More information

Astro 21 first lecture. stars are born but also helps us study how. Density increases in the center of the star. The core does change from hydrogen to

Astro 21 first lecture. stars are born but also helps us study how. Density increases in the center of the star. The core does change from hydrogen to Astro 21 first lecture The H-R H R Diagram helps us study how stars are born but also helps us study how they die. Stars spend most of their lives as main sequence stars. The core does change from hydrogen

More information

Star & Planet Formation

Star & Planet Formation Star & Planet Formation A rotating, collapsing cloud will flatten into a disk, with a protostar at the center. (Planets can form in the disk!) The collapse will continue until gravity is opposed by another

More information

Daily Science 03/30/2017

Daily Science 03/30/2017 Daily Science 03/30/2017 The atmospheres of different planets contain different gases. Which planet is most likely Earth? a. planet 1 b. planet 2 c. planet 3 d. planet 4 KeslerScience.com Can you name

More information

What is a star? A body of gases that gives off tremendous amounts of energy in the form of light & heat. What star is closest to the earth?

What is a star? A body of gases that gives off tremendous amounts of energy in the form of light & heat. What star is closest to the earth? Stars What is a star? A body of gases that gives off tremendous amounts of energy in the form of light & heat. What star is closest to the earth? Answer: The SUN It s about 150,000,000 km from earth =

More information

The Life Cycles of Stars. Modified from Information provided by: Dr. Jim Lochner, NASA/GSFC

The Life Cycles of Stars. Modified from Information provided by: Dr. Jim Lochner, NASA/GSFC The Life Cycles of Stars Modified from Information provided by: Dr. Jim Lochner, NASA/GSFC Twinkle, Twinkle, Little Star... What do you see? How I Wonder What You Are... Stars have: Different Colors -

More information

Tuesday, August 27, Stellar Astrophysics

Tuesday, August 27, Stellar Astrophysics Stellar Astrophysics Policies No Exams Homework 65% Project 35% Oral Presentation 5% More on the project http://myhome.coloradomesa.edu/ ~jworkman/teaching/fall13/396/ syllabus396.pdf You need to self

More information

structures: existence stars

structures: existence stars structures: existence stars Kelvin s paradox Some unknown source of energy laid down in the store house of creation Kelvin s paradox The gravitational binding energy of the mass of the Sun after it falls

More information

Heading for death. q q

Heading for death. q q Hubble Photos Credit: NASA, The Hubble Heritage Team (STScI/AURA) Heading for death. q q q q q q Leaving the main sequence End of the Sunlike star The helium core The Red-Giant Branch Helium Fusion Helium

More information

ASTR Midterm 1 Phil Armitage, Bruce Ferguson

ASTR Midterm 1 Phil Armitage, Bruce Ferguson ASTR 1120-001 Midterm 1 Phil Armitage, Bruce Ferguson FIRST MID-TERM EXAM FEBRUARY 16 th 2006: Closed books and notes, 1 hour. Please PRINT your name and student ID on the places provided on the scan sheet.

More information

The Sun Our Extraordinary Ordinary Star

The Sun Our Extraordinary Ordinary Star The Sun Our Extraordinary Ordinary Star 1 Guiding Questions 1. What is the source of the Sun s energy? 2. What is the internal structure of the Sun? 3. How can astronomers measure the properties of the

More information

An Overview of the Details

An Overview of the Details The Sun Our Extraordinary Ordinary Star 1 Guiding Questions 1. What is the source of the Sun s energy? 2. What is the internal structure of the Sun? 3. How can astronomers measure the properties of the

More information

Stellar Evolution. The lives of low-mass stars. And the lives of massive stars

Stellar Evolution. The lives of low-mass stars. And the lives of massive stars Stellar Evolution The lives of low-mass stars And the lives of massive stars The Structure of the Sun Let s review: The Sun is held together by what force? The inward force is balanced by what other force?

More information

Announcements. Lecture 11 Properties of Stars. App Bright = L / 4!d 2

Announcements. Lecture 11 Properties of Stars. App Bright = L / 4!d 2 Announcements Quiz#3 today at the end of 60min lecture. Homework#3 will be handed out on Thursday. Due October 14 (next Thursday) Review of Mid-term exam will be handed out next Tuesday. Mid-term exam

More information

From Last Time: We can more generally write the number densities of H, He and metals.

From Last Time: We can more generally write the number densities of H, He and metals. From Last Time: We can more generally write the number densities of H, He and metals. n H = Xρ m H,n He = Y ρ 4m H, n A = Z Aρ Am H, How many particles results from the complete ionization of hydrogen?

More information

Unit 2 Lesson 2 Stars. Copyright Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 2 Stars. Copyright Houghton Mifflin Harcourt Publishing Company Florida Benchmarks SC.8.N.1.6 Understand that scientific investigations involve the collection of relevant empirical evidence, the use of logical reasoning, and the application of imagination in devising

More information

The Life Histories of Stars I. Birth and Violent Lives

The Life Histories of Stars I. Birth and Violent Lives The Life Histories of Stars I Birth and Violent Lives Stellar evolution--first problem for new discipline of astrophysics What is a star? What is it made of? How does it produce and release energy? How

More information

Dark Matter. About 90% of the mass in the universe is dark matter Initial proposals: MACHOs: massive compact halo objects

Dark Matter. About 90% of the mass in the universe is dark matter Initial proposals: MACHOs: massive compact halo objects 1 Dark Matter About 90% of the mass in the universe is dark matter Initial proposals: MACHOs: massive compact halo objects Things like small black holes, planets, other big objects They must be dark (so

More information

Birth & Death of Stars

Birth & Death of Stars Birth & Death of Stars Objectives How are stars formed How do they die How do we measure this The Interstellar Medium (ISM) Vast clouds of gas & dust lie between stars Diffuse hydrogen clouds: dozens of

More information

Teacher of the Week DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS

Teacher of the Week DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS Teacher of the Week DEVIL PHYSICS THE BADDEST CLASS ON CAMPUS IB PHYSICS TSOKOS LESSON E-2 STELLAR RADIATION IB Assessment Statements Topic E-2, Stellar Radiation and Stellar Types Energy Source E.2.1.

More information

18. Stellar Birth. Initiation of Star Formation. The Orion Nebula: A Close-Up View. Interstellar Gas & Dust in Our Galaxy

18. Stellar Birth. Initiation of Star Formation. The Orion Nebula: A Close-Up View. Interstellar Gas & Dust in Our Galaxy 18. Stellar Birth Star observations & theories aid understanding Interstellar gas & dust in our galaxy Protostars form in cold, dark nebulae Protostars evolve into main-sequence stars Protostars both gain

More information

An Overview of the Details

An Overview of the Details Guiding Questions The Sun Our Extraordinary Ordinary Star 1. What is the source of the Sun s energy? 2. What is the internal structure of the Sun? 3. How can astronomers measure the properties of the Sun

More information