The Spectra of Stars and Binary Stars (Masses and Radii)

Size: px
Start display at page:

Download "The Spectra of Stars and Binary Stars (Masses and Radii)"

Transcription

1 The Spectra of Stars and Binary Stars (Masses and Radii)

2 Colors of Stars Stars are made of hot, dense gas Con$nuous spectrum from the lowest visible layers ( photosphere ). Approximates a blackbody spectrum. From Wien s Law, we expect: hojer stars appear BLUE (T=10,000 50,000 K) middle stars appear YELLOW (T~6000K) cool stars appear RED (T~3000K)

3

4 Spectra of Stars Hot, dense lower photosphere of a star is surrounded by thinner (but szll fairly hot) atmosphere. Produces an Absorp$on Line spectrum. Lines come from the elements in the stellar atmosphere.

5

6 Spectral ClassificaZon of Stars Astronomers nozced that stellar spectra showed many similarizes. Can stars be classified by their spectra? Draper Survey at Harvard ( ): ObjecZve Prism Photography obtained spectra of >100,000 stars hired women as computers to analyze spectra

7 ObjecZve Prism Spectra

8 Harvard ClassificaZon Edward Pickering s first ajempt at a systemazc spectral classificazon: Sort by Hydrogen absorpzon line strength Spectral Type A = strongest Hydrogen lines followed by types B, C, D, etc. (weaker) Problem: Other lines followed no discernible pajerns.

9 Edward Pickering Harvard Computers (c. 1900)

10 Annie Jump Cannon Leader of Pickering s computers, she nozced subtle pajerns among metal lines. Re arranged Pickering s ABC spectral types, throwing out most as redundant. Lef 7 primary and 3 secondary classes: O B A F G K M (R N S) Unifying factor: Temperature

11 Annie Jump Cannon

12 The Spectral Sequence O B A F G K M L T Hotter Cooler 50,000K 2000K Bluer Redder Spectral Sequence is a Temperature Sequence

13 Spectral Types

14 The Spectral Sequence is a Temperature Sequence Gross differences among the spectral types are due to differences in Temperature. ComposiZon differences are minor at best. Why? Demonstrated by Cecilia Payne Gaposhkin in 1920 s What lines you see depends on the state of excita$on and ioniza$on of the gas.

15 Example: Hydrogen Lines Visible Hydrogen absorpzon lines come from the second excited state. B Stars (15 30,000 K): Most of H is ionized, so only very weak H lines. A Stars (10,000 K): Ideal excitazon condizons, strongest H lines. G Stars (6000 K): Too cool, lijle excited H, so only weak H lines.

16

17 O Stars HoJest Stars: T>30,000 K Strong lines of He + No lines of H

18 B Stars T=15,000 30,000 K Strong lines of He Very weak lines of H

19 A Stars T = 10, K Strong lines of H Weak lines of Ca+

20 F Stars T = K weaker lines of H Ca + lines growing stronger first weak metal lines appear

21 G Stars T = K Strong lines of Ca +, Fe +, & other metals much weaker H lines The Sun is a G type Star

22 K Stars Cool Stars: T = K Strongest metal lines H lines praczcally gone first weak CH & CN molecular bands

23 M Stars Very cool stars: T = K Strong molecular bands (especially TiO) No lines of H

24 L & T Stars Coolest stars: T < 2000 K Discovered in 1999 Strong molecular bands Metal hydride (CrH & FeH) Methane (CH4) in T stars Probably not stars at all

25 Modern Synthesis: The M K System An understanding of atomic physics and bejer techniques permit finer disznczons. Morgan Keenan (M K) ClassificaZon System: Start with Harvard classes: O B A F G K M L T Subdivide each class into numbered subclasses: A0 A1 A2 A3... A9

26 Examples: The Sun: G2 star Other Bright Stars: Betelgeuse: M2 star (Orion) Rigel: B8 star (Orion) Sirius: A1 star (Canis Major) Aldebaran: K5 star (Taurus)

27 Binary Stars Apparent Binaries Chance projeczon of two disznct stars along the line of sight. Ofen at very different distances. True Binary Stars: A pair of stars bound by gravity. Orbit each other about their center of mass. Between 20% and 80% of all stars are binaries.

28 Types of Binaries Visual Binary: Can see both stars & follow their orbits over Zme. Spectroscopic Binary: Cannot separate the two stars, but see their orbit mozons as Doppler shifs in their spectra. Eclipsing Binary: Cannot separate stars, but see the total brightness drop when they periodically eclipse each other.

29 Visual Binary

30 Center of Mass Two stars orbit about their center of mass: a 2 a 1 M 2 M a 1 Measure semi-major axis, a, from projected orbit and the distance. Relative positions give: M 1 / M 2 = a 2 / a 1

31 Measuring Masses Newton s Form of Kepler s Third Law: Measure Period, P, by following the orbit. Measure semi major axis, a, and mass RaZo (M 1 /M 2 ) from projected orbit.

32 Problems We need to follow the orbits long enough to trace them out in detail. This can take decades. Need to work out the projeczon on the sky. Everything depends crizcally on the distance: semi major axis depends on d derived mass depends on d 3!!

33 Spectroscopic Binaries Most binaries are too far away to see both stars separately. But, you can detect their orbital mozons by the periodic Doppler shics of their spectral lines. Determine the orbit period & size from velocizes.

34 B A B A B A A B

35 Problems Cannot see the two stars separately: Semi major axis must be guessed from orbit Can t tell how the orbit is Zlted on the sky Everything depends crizcally on knowing the distance.

36 Eclipsing Binaries Two stars orbizng nearly edge on. See a periodic drop in brightness as one star eclipses the other. Combine with spectra which measure orbital speeds. With the best data, one can find the masses without having to know the distance!

37 Eclipsing Binary Brightness Time

38 Problems Eclipsing Binaries are very rare Orbital plane must line up just right Measurement of the eclipse light curves complicated by details: ParZal eclipses yield less accurate numbers. Atmospheres of the stars sofen edges. Close binaries can be Zdally distorted.

39 Stellar Masses Masses are known for only ~200 stars. Range: ~0.1 to 50 Solar Masses Stellar masses can only be measured for binary stars.

40 Stellar Radii Very difficult to measure because stars are so far away. Methods: Eclipsing binaries (need distance) Interferometry (single stars) Lunar OccultaZon (single stars) Radii are only measured for about 500 stars

41 Summary: Color of a star depends on its Temperature Red Stars are Cooler Blue Stars are HoJer Spectral ClassificaZon Classify stars by their spectral lines Spectral differences mostly due to Temperature Spectral Sequence (Temperature Sequence) O B A F G K M L T

42 Types of Binary Stars Visual Spectroscopic Eclipsing Summary: Only way to measure stellar masses: Only ~150 stars Radii are measured for very few stars.

43 QuesZons: What does the temperature of a star mean? Are there stars with temperatures higher than 50000K? Are hojer stars brighter than cooler stars? Are they more luminous? Why did it take so long to find L & T stars?

44 QuesZons What star do we know the mass of very precisely? Why is it so unlikely that binaries are in eclipsing systems? Most binaries are seen as spectroscopic. Why? How can we know the sizes of more stars than masses?

Lecture 14: Studying the stars. Astronomy 111 Monday October 16, 2017

Lecture 14: Studying the stars. Astronomy 111 Monday October 16, 2017 Lecture 14: Studying the stars Astronomy 111 Monday October 16, 2017 Reminders Homework #7 due Monday I will give a lecture on DES and LIGO tomorrow at 4pm in the Mitchell Institute Studying the stars

More information

Sun. Sirius. Tuesday, February 21, 2012

Sun. Sirius. Tuesday, February 21, 2012 Spectral Classification of Stars Sun Sirius Stellar Classification Spectral Lines H Fe Na H Ca H Spectral Classification of Stars Timeline: 1890s Edward C. Pickering (1846-1919) and Williamina P. Fleming

More information

Atomic Spectra in Astrophysics

Atomic Spectra in Astrophysics Atomic Spectra in Astrophysics Potsdam University : Dr. Lidia Oskinova lida@astro.physik.uni-potsdam.de Fundamentals of stellar classification 01 Stars are made of hot, dense gas Continuous spectrum from

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D.

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D. Astronomy 113 Dr. Joseph E. Pesce, Ph.D. The Nature of Stars 8-2 Parallax For nearby stars - measure distances with parallax July 1 AU d p A A A January ³ d = 1/p (arcsec) [pc] ³ 1pc when p=1arcsec; 1pc=206,265AU=3

More information

13.3 Spectra of Stars

13.3 Spectra of Stars 13.3 Spectra of Stars A star's spectrum depicts the energy it emits at each wavelength and is perhaps the single most important thing we can know about the star. From the spectrum we can find the star's

More information

15.1 Properties of Stars

15.1 Properties of 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 do we measure stellar masses? How do we measure

More information

The Physics of Light, part 2. Astronomy 111

The Physics of Light, part 2. Astronomy 111 Lecture 7: The Physics of Light, part 2 Astronomy 111 Spectra Twinkle, twinkle, little star, How I wonder what you are. Every type of atom, ion, and molecule has a unique spectrum Ion: an atom with electrons

More information

Stars - spectral types

Stars - spectral types Stars - spectral types 1901: Led by Annie Jump Cannon, Harvard astronomers looked at the spectra of >200,000 stars. Classified them as A, B, C etc. Cannon rearranged them into OBAFGKM based on how lines

More information

Chapter 10 Measuring the Stars

Chapter 10 Measuring the Stars Chapter 10 Measuring the Stars Some of the topics included in this chapter Stellar parallax Distance to the stars Stellar motion Luminosity and apparent brightness of stars The magnitude scale Stellar

More information

ASTR-1020: Astronomy II Course Lecture Notes Section III

ASTR-1020: Astronomy II Course Lecture Notes Section III ASTR-1020: Astronomy II Course Lecture Notes Section III 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

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

Lecture 12: Distances to stars. Astronomy 111

Lecture 12: Distances to stars. Astronomy 111 Lecture 12: Distances to stars Astronomy 111 Why are distances important? Distances are necessary for estimating: Total energy released by an object (Luminosity) Masses of objects from orbital motions

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

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

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

The Sun and the Stars

The Sun and the Stars Classification of stellar spectra Potted History : 1802 William Wallaston showed that the spectrum of the sun is not simply a continuous spectrum, but is broken up by a series of dark lines (absorption

More information

Family of stars. Fred Sarazin Physics Department, Colorado School of Mines. PHGN324: Family of stars

Family of stars. Fred Sarazin Physics Department, Colorado School of Mines. PHGN324: Family of stars Family of stars Reminder: the stellar magnitude scale In the 1900 s, the magnitude scale was defined as follows: a difference of 5 in magnitude corresponds to a change of a factor 100 in brightness. Dm

More information

Parallax: Measuring the distance to Stars

Parallax: Measuring the distance to Stars Measuring the Stars Parallax: Measuring the distance to Stars Use Earth s orbit as baseline Parallactic angle = 1/2 angular shift Distance from the Sun required for a star to have a parallactic angle of

More information

Stars: some basic characteristics

Stars: some basic characteristics Stars: some basic characteristics Stars! How bright are they? How massive are they? What are the different types? How long do they live? How hot are they? Stellar brightness and luminosity The apparent

More information

Assignments for Monday Oct. 22. Read Ch Do Online Exercise 10 ("H-R Diagram" tutorial)

Assignments for Monday Oct. 22. Read Ch Do Online Exercise 10 (H-R Diagram tutorial) Assignments for Monday Oct. 22 Read Ch. 13 + Do Online Exercise 10 ("H-R Diagram" tutorial) Luminosity passing through each sphere is the same. Area of sphere: 4π(radius) 2 Divide luminosity by area to

More information

Measuring the Stars. The measurement of distances The family of distance-measurement techniques used by astronomers to chart the universe is called

Measuring the Stars. The measurement of distances The family of distance-measurement techniques used by astronomers to chart the universe is called Measuring the Stars How to measure: Distance Stellar motion Luminosity Temperature Size Evolutionary stage (H-R diagram) Cosmic distances Mass The measurement of distances The family of distance-measurement

More information

Review of Star Intro. PHYSICS 162 Lecture 7a 1

Review of Star Intro. PHYSICS 162 Lecture 7a 1 Review of Star Intro Parallax - geometric method of determining star distance Absolute and apparent luminosity. Temperature Spectrum: What characterizes the star s surface Is related to its temperature

More information

The Family of Stars. Chapter 13. Triangulation. Trigonometric Parallax. Calculating Distance Using Parallax. Calculating Distance Using Parallax

The Family of Stars. Chapter 13. Triangulation. Trigonometric Parallax. Calculating Distance Using Parallax. Calculating Distance Using Parallax The Family of Stars Chapter 13 Measuring the Properties of Stars 1 Those tiny glints of light in the night sky are in reality huge, dazzling balls of gas, many of which are vastly larger and brighter than

More information

Astr 2320 Tues. March 7, 2017 Today s Topics

Astr 2320 Tues. March 7, 2017 Today s Topics Astr 2320 Tues. March 7, 2017 Today s Topics Chapter 13: Stars: Binary Stars Determination of Stellar Properties vi Binary Stars Classification of Binary Stars Visual Binaries Both stars visible Only one

More information

Lines of Hydrogen. Most prominent lines in many astronomical objects: Balmer lines of hydrogen

Lines of Hydrogen. Most prominent lines in many astronomical objects: Balmer lines of hydrogen The Family of Stars Lines of Hydrogen Most prominent lines in many astronomical objects: Balmer lines of hydrogen The Balmer Thermometer Balmer line strength is sensitive to temperature: Most hydrogen

More information

Distances to the stars Friedrich Bessel Cygni 10 light years. Just beat Struve and Henderson who measured Vega and α Centauri respectively.

Distances to the stars Friedrich Bessel Cygni 10 light years. Just beat Struve and Henderson who measured Vega and α Centauri respectively. Distances to the stars Friedrich Bessel 1838 61 Cygni 10 light years. Just beat Struve and Henderson who measured Vega and α Centauri respectively. Distances to the stars the technique p < 1arcsecond d

More information

FYI: Spectral Classification & Stellar Spectra. 1. Read FYI: Spectral Classification A Look Back and FYI: Stellar Spectra What s in a Star?

FYI: Spectral Classification & Stellar Spectra. 1. Read FYI: Spectral Classification A Look Back and FYI: Stellar Spectra What s in a Star? FYI: Spectral Classification & Stellar Spectra E3:R1 1. Read FYI: Spectral Classification A Look Back and FYI: Stellar Spectra What s in a Star? As you read use the spaces below to write down any information

More information

A Stellar Spectra 3. Stars shine at night (during the day too!). A star is a self-luminous sphere of gas. Stars are held together by gravity.

A Stellar Spectra 3. Stars shine at night (during the day too!). A star is a self-luminous sphere of gas. Stars are held together by gravity. Stellar Spectra Relativity and Astrophysics Lecture 12 Terry Herter Outline What is a star? Stellar Spectra Kirchhoff s Laws Spectral Classification Spectral Types: O B A F G K M L T Stellar Photometry

More information

Stars: Intro & Classification

Stars: Intro & Classification Stars: Intro & Classification Astronomy 1 Elementary Astronomy LA Mission College Spring F2015 Quotes & Cartoon of the Day The wonder is, not that the field of stars of so vast, but that man has measured

More information

Types of Stars 1/31/14 O B A F G K M. 8-6 Luminosity. 8-7 Stellar Temperatures

Types of Stars 1/31/14 O B A F G K M. 8-6 Luminosity. 8-7 Stellar Temperatures Astronomy 113 Dr. Joseph E. Pesce, Ph.D. The Nature of Stars For nearby stars - measure distances with parallax 1 AU d p 8-2 Parallax A January ³ d = 1/p (arcsec) [pc] ³ 1pc when p=1arcsec; 1pc=206,265AU=3

More information

Parallax: Space Observatories. Stars, Galaxies & the Universe Announcements. Stars, Galaxies & Universe Lecture #7 Outline

Parallax: Space Observatories. Stars, Galaxies & the Universe Announcements. Stars, Galaxies & Universe Lecture #7 Outline Stars, Galaxies & the Universe Announcements HW#4: posted Thursday; due Monday (9/20) Reading Quiz on Ch. 16.5 Monday (9/20) Exam #1 (Next Wednesday 9/22) In class (50 minutes) first 20 minutes: review

More information

Chapter 15 Lecture. The Cosmic Perspective Seventh Edition. Surveying the Stars Pearson Education, Inc.

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

More information

Chapter 15 Surveying the Stars Pearson Education, Inc.

Chapter 15 Surveying the Stars Pearson Education, Inc. 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? 1. How

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

Stars. Properties of Stars

Stars. Properties of Stars Stars Properties of Stars Do all stars appear the same? How are they different? Which one looks the coolest? Hottest? Are they all the same brightness? Do they all look the same size? Luminosity: Amount

More information

Astr 5465 Feb. 6, 2018 Today s Topics

Astr 5465 Feb. 6, 2018 Today s Topics Astr 5465 Feb. 6, 2018 Today s Topics Stars: Binary Stars Determination of Stellar Properties via Binary Stars Classification of Binary Stars Visual Binaries Both stars visible Only one star visible Spectroscopic

More information

301 Physics 1/20/09. The Family of Stars. Chapter 12. Triangulation. Trigonometric Parallax. Course/Syllabus Overview Review of 301 stuff Start Ch.

301 Physics 1/20/09. The Family of Stars. Chapter 12. Triangulation. Trigonometric Parallax. Course/Syllabus Overview Review of 301 stuff Start Ch. 1/20/09 Course/Syllabus Overview Review of 301 stuff Start Ch. 12 More than just knowing various facts Understand how we arrive at these conclusions 301 Physics Physics Concepts Light Properties of (frequency,wavelength,energy)

More information

The Amazing Power of Starlight

The Amazing Power of Starlight The Amazing Power of Starlight Chapter 6 Just by analyzing the light received from a star, astronomers can retrieve information about a star s Starlight and Atoms 1. Total energy output 2. Surface temperature

More information

My God, it s full of stars! AST 248

My God, it s full of stars! AST 248 My God, it s full of stars! AST 248 N * The number of stars in the Galaxy N = N * f s f p n h f l f i f c L/T The Galaxy M31, the Andromeda Galaxy 2 million light years from Earth The Shape of the Galaxy

More information

HOMEWORK - Chapter 17 The Stars

HOMEWORK - Chapter 17 The Stars Astronomy 20 HOMEWORK - Chapter 7 The Stars Use a calculator whenever necessary. For full credit, always show your work and explain how you got your answer in full, complete sentences on a separate sheet

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

Chapter 6. Atoms and Starlight

Chapter 6. Atoms and Starlight Chapter 6 Atoms and Starlight What is light? Light is an electromagnetic wave. Wavelength and Frequency wavelength frequency = speed of light = constant Particles of Light Particles of light are called

More information

Ohio University - Lancaster Campus slide 1 of 47 Spring 2009 PSC 100. A star s color, temperature, size, brightness and distance are all related!

Ohio University - Lancaster Campus slide 1 of 47 Spring 2009 PSC 100. A star s color, temperature, size, brightness and distance are all related! Ohio University - Lancaster Campus slide 1 of 47 A star s color, temperature, size, brightness and distance are all related! Ohio University - Lancaster Campus slide 2 of 47 The Beginnings Late 1800 s,

More information

Spectral Classification of Stars

Spectral Classification of Stars Sun Sirius Stellar Classification Spectral Lines CaH H Fe Na H Timeline: Edward C. Pickering (1846-1919) and Williamina P. Fleming 1890s (1857-1911) label spectra alphabetically according to strength of

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

5. A particular star has an angle of parallax of 0.2 arcsecond. What is the distance to this star? A) 50 pc B) 2 pc C) 5 pc D) 0.

5. A particular star has an angle of parallax of 0.2 arcsecond. What is the distance to this star? A) 50 pc B) 2 pc C) 5 pc D) 0. Name: Date: 1. How far away is the nearest star beyond the Sun, in parsecs? A) between 1 and 2 pc B) about 12 pc C) about 4 pc D) between 1/2 and 1 pc 2. Parallax of a nearby star is used to estimate its

More information

Exam 1 will cover. The Day of the Exam. Astronomy Picture of the Day: Today s Class: Measuring temperatures of stars

Exam 1 will cover. The Day of the Exam. Astronomy Picture of the Day: Today s Class: Measuring temperatures of stars September 25, 2013 Reading: Chapter 15, section 15.1. Exam 1 next class! Review Session tomorrow night, Sep. 26, at 7 pm in Duane G2B47. Naked eye observing session tonight at 8 pm. Volunteers for Astronomy

More information

Astronomy. The Nature of Stars

Astronomy. The Nature of Stars Astronomy A. Dayle Hancock adhancock@wm.edu Small 239 Office hours: MTWR 10-11am The Nature of Stars Distances to stars A Star's brightness and Luminosity A Magnitude scale Color indicates a Star's temperature

More information

Reading and Announcements. Read Chapters 8.3, 11.5, 12.1 Quiz #5, Thursday, March 21 Homework #5 due Tuesday, March 19

Reading and Announcements. Read Chapters 8.3, 11.5, 12.1 Quiz #5, Thursday, March 21 Homework #5 due Tuesday, March 19 Reading and Announcements Read Chapters 8.3, 11.5, 12.1 Quiz #5, Thursday, March 21 Homework #5 due Tuesday, March 19 Measurements of Star Properties Apparent brightness Direct measurement Parallax Distance

More information

Properties of Stars (continued) Some Properties of Stars. What is brightness?

Properties of Stars (continued) Some Properties of Stars. What is brightness? Properties of Stars (continued) Some Properties of Stars Luminosity Temperature of the star s surface Mass Physical size 2 Chemical makeup 3 What is brightness? Apparent brightness is the energy flux (watts/m

More information

Determining the Properties of the Stars

Determining the Properties of the Stars Determining the Properties of the Stars This set of notes by Nick Strobel covers: The properties of stars--their distances, luminosities, compositions, velocities, masses, radii, and how we determine those

More information

V. Stars.

V. Stars. V. Stars http://sgoodwin.staff.shef.ac.uk/phy111.html 0. The local HR diagram We saw that locally we can make an HR diagram of absolute luminosity against temperature. We find a main sequence, giants and

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

The Temperatures of Stars. Image credit: NOAO

The Temperatures of Stars. Image credit: NOAO The Temperatures of Stars Image credit: NOAO Understanding Stars Starlight contains a lot of information. This information doesn t decay or expire as the light travels through space. By examining the light

More information

Photosphere. Bob Stein s simulation movie. Chromosphere. Corona. Solar wind

Photosphere. Bob Stein s simulation movie. Chromosphere. Corona. Solar wind Photosphere Layer from which light escapes directly into space. Photosphere is what we see. Light from lower layers scatters. Q: Suppose we observe the neutrinos from the sun. The size of the sun when

More information

Measuring Radial & Tangential Velocity. Radial velocity measurement. Tangential velocity measurement. Measure the star s Doppler shift

Measuring Radial & Tangential Velocity. Radial velocity measurement. Tangential velocity measurement. Measure the star s Doppler shift 17. The Nature of the Stars Parallax reveals stellar distance Stellar distance reveals luminosity Luminosity reveals total energy production The stellar magnitude scale Surface temperature determines stellar

More information

Stars III The Hertzsprung-Russell Diagram

Stars III The Hertzsprung-Russell Diagram Stars III The Hertzsprung-Russell Diagram Attendance Quiz Are you here today? (a) yes Here! (b) no (c) here is such a 90 s concept Today s Topics (first half) Spectral sequence and spectral types Spectral

More information

Astronomy 110 Homework #07 Assigned: 03/06/2007 Due: 03/13/2007. Name: (Answer Key)

Astronomy 110 Homework #07 Assigned: 03/06/2007 Due: 03/13/2007. Name: (Answer Key) Astronomy 110 Homework #07 Assigned: 03/06/2007 Due: 03/13/2007 Name: (Answer Key) Directions: Listed below are twenty (20) multiple-choice questions based on the material covered by the lectures thus

More information

Astronomy 421. Lecture 8: Binary stars

Astronomy 421. Lecture 8: Binary stars Astronomy 421 Lecture 8: Binary stars 1 Key concepts: Binary types How to use binaries to determine stellar parameters The mass-luminosity relation 2 Binary stars So far, we ve looked at the basic physics

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

Test Ques4ons. Median Grade: 82/100 High Score: 99/100

Test Ques4ons. Median Grade: 82/100 High Score: 99/100 Day 11: Stars Review of Test Ar4cle Sharing Reading/Mastering Astronomy Ques4ons Lecture on Spectral Type Break Lecture on Hertzsprung- Russell Diagram L- T: H- R Diagram, p 117 Summary Test Ques4ons Median

More information

Chapter 15 Reading Quiz Clickers. The Cosmic Perspective Seventh Edition. Surveying the Stars Pearson Education, Inc.

Chapter 15 Reading Quiz Clickers. The Cosmic Perspective Seventh Edition. Surveying the Stars Pearson Education, Inc. Reading Quiz Clickers The Cosmic Perspective Seventh Edition Surveying the Stars 15.1 Properties of Stars How do we measure stellar luminosities? How do we measure stellar temperatures? How do we measure

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Homework Ch 7, 8, 9 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Our most detailed knowledge of Uranus and Neptune comes from 1) A) the

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

OTHER MOTIONS. Just so far away they appear to move very slowly

OTHER MOTIONS. Just so far away they appear to move very slowly OTHER MOTIONS The position of a nearby star changing over a year gives us parallax Stars can also move on their own Real motion, not just our point of view They are just balls of gas and are moving around

More information

Observed Properties of Stars - 2 ASTR 2120 Sarazin

Observed Properties of Stars - 2 ASTR 2120 Sarazin Observed Properties of Stars - 2 ASTR 2120 Sarazin Properties Location Distance Speed Radial velocity Proper motion Luminosity, Flux Magnitudes Magnitudes Hipparchus 1) Classified stars by brightness,

More information

Temperature, Blackbodies & Basic Spectral Characteristics.

Temperature, Blackbodies & Basic Spectral Characteristics. Temperature, Blackbodies & Basic Spectral Characteristics. Things that have one primary temperature but also exhibit a range of temperatures are known in physics as blackbodies. They radiate energy thermally.

More information

Measuring Radial & Tangential Velocity. Radial velocity measurement. Tangential velocity measurement. Measure the star s Doppler shift

Measuring Radial & Tangential Velocity. Radial velocity measurement. Tangential velocity measurement. Measure the star s Doppler shift 17. The Nature of the Stars Parallax reveals stellar distance Stellar distance reveals luminosity Luminosity reveals total energy production The stellar magnitude scale Surface temperature determines stellar

More information

The Hertzprung-Russell Diagram. The Hertzprung-Russell Diagram. Question

The Hertzprung-Russell Diagram. The Hertzprung-Russell Diagram. Question Key Concepts: Lecture 21: Measuring the properties of stars (cont.) The Hertzsprung-Russell (HR) Diagram (L versus T) The Hertzprung-Russell Diagram The Stefan-Boltzmann Law: flux emitted by a black body

More information

a. Star A c. The two stars are the same distance b. Star B d. Not enough information

a. Star A c. The two stars are the same distance b. Star B d. Not enough information Name: Astro 102 S17 Test 1 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Your test is Version A. Please fill in the circle for A for this question on

More information

Galaxies and Stars. 3. Base your answer to the following question on The reaction below represents an energy-producing process.

Galaxies and Stars. 3. Base your answer to the following question on The reaction below represents an energy-producing process. Galaxies and Stars 1. To an observer on Earth, the Sun appears brighter than the star Rigel because the Sun is A) hotter than Rigel B) more luminous than Rigel C) closer than Rigel D) larger than Rigel

More information

CASE STUDY FOR USE WITH SECTION B

CASE STUDY FOR USE WITH SECTION B GCE A level 325/0-A PHYSICS PH5 Assessment Unit CASE STUDY FOR USE WITH SECTION B Pre-Release Material To be opened on receipt A new copy of this Case Study will be given out in the examination 325 0A00

More information

Measuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam]

Measuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam] Measuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam] Although we can be certain that other stars are as complex as the Sun, we will try to

More information

Lecture Outlines. Chapter 17. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.

Lecture Outlines. Chapter 17. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc. Lecture Outlines Chapter 17 Astronomy Today 8th Edition Chaisson/McMillan Chapter 17 Measuring the Stars Units of Chapter 17 17.1 The Solar Neighborhood 17.2 Luminosity and Apparent Brightness 17.3 Stellar

More information

Observed Properties of Stars - 2 ASTR 2110 Sarazin

Observed Properties of Stars - 2 ASTR 2110 Sarazin Observed Properties of Stars - 2 ASTR 2110 Sarazin Properties Location Distance Speed Radial velocity Proper motion Luminosity, Flux Magnitudes Magnitudes Stellar Colors Stellar Colors Stellar Colors Stars

More information

Spectral Classification of Stars

Spectral Classification of Stars Department of Physics and Geology Spectral Classification of Stars Astronomy 1402 Part 1: Background Spectral Classification of Stars 1.1 Spectral Types: O, B, A, F, G, K, M On a dark, clear night far

More information

Review: Properties of a wave

Review: Properties of a wave Radiation travels as waves. Waves carry information and energy. Review: Properties of a wave wavelength (λ) crest amplitude (A) trough velocity (v) λ is a distance, so its units are m, cm, or mm, etc.

More information

The Sun (chapter 14) some of this is review from quiz 3, but you should

The Sun (chapter 14) some of this is review from quiz 3, but you should Astro20 / Harpell Topics for Quiz 4 The quiz will have 20 multiple choice questions; several "fill in the blanks" about five short essay questions that may require sketches.. If you can answer everything

More information

Astronomy 122 Outline

Astronomy 122 Outline Astronomy 122 Outline This Class (Lecture 12): Stars Next Class: The Nature of Stars Homework #5 is posted. Nightlabs have started! Stellar properties Parallax (distance) Colors Spectral Classes Music:

More information

Chapter 8: The Family of Stars

Chapter 8: The Family of Stars Chapter 8: The Family of Stars Motivation We already know how to determine a star s surface temperature chemical composition surface density In this chapter, we will learn how we can determine its distance

More information

Lecture 21. Stellar Size

Lecture 21. Stellar Size Lecture 21 Stellar Mass; The Main Sequence Visual and Spectroscopic Binaries Mass and the Main Sequence Explaining the Main Sequence Mar 8, 2006 Astro 100 Lecture 21 1 Stellar Size Taking ratios to the

More information

Stellar Masses: Binary Stars

Stellar Masses: Binary Stars Stellar Masses: Binary Stars The HR Diagram Again A Diagram for People Q: What is happening here? A: People grow. They are born small, and then grow in height and mass as they age (with a fair bit of individual

More information

TWINKLE, TWINKLE LITTLE STAR HOW ASTRONOMERS KNOW WHAT YOU ARE. View the white lights in the room with the diffraction glasses. What do you see?

TWINKLE, TWINKLE LITTLE STAR HOW ASTRONOMERS KNOW WHAT YOU ARE. View the white lights in the room with the diffraction glasses. What do you see? Name Partner(s) Section Date TWINKLE, TWINKLE LITTLE STAR HOW ASTRONOMERS KNOW WHAT YOU ARE Since journeys to the stars are not possible at this time, astronomers use every source of information available

More information

Discussion. Summary Clicker -- Solar Wind. What are effects of solar activity on our technological society? A. Auroral

Discussion. Summary Clicker -- Solar Wind. What are effects of solar activity on our technological society? A. Auroral ASTR 1040 Accel Astro: Stars & Galaxies Prof. Juri Toomre TA: Nicholas Nelson Lecture 10 Thur 10 Feb 11 zeus.colorado.edu/astr1040-toomre toomre Planetary Nebula NGC 3132 Today What can we measure in other

More information

Chapter 15 Surveying the Stars. Properties of Stars. Parallax and Distance. Distances Luminosities Temperatures Radii Masses

Chapter 15 Surveying the Stars. Properties of Stars. Parallax and Distance. Distances Luminosities Temperatures Radii Masses hapter 15 Surveying the Stars Properties of Stars istances Luminosities s Radii Masses istance Use radar in Solar System, but stars are so far we use parallax: apparent shift of a nearby object against

More information

Stars: Stars and their Properties

Stars: Stars and their Properties Stars: Stars and their Properties Astronomy 110 Class 10 WHEN I heard the learn d astronomer; When the proofs, the figures, were ranged in columns before me; When I was shown the charts and the diagrams,

More information

ASTRO Lecture to the overhead that we had yesterday. This is that color picture showing all the different

ASTRO Lecture to the overhead that we had yesterday. This is that color picture showing all the different ASTRO Lecture 39 1 We re gonna continue our discussion today of stellar spectra. I wanted to go back to the overhead that we had yesterday. This is that color picture showing all the different kinds of

More information

Properties of Stars & H-R Diagram

Properties of Stars & H-R Diagram Properties of Stars & H-R Diagram What is a star? A cloud of gas, mainly hydrogen and helium The core is so hot/dense that nuclear fusion can occur. The fusion converts light nuclei (elements) into heavier

More information

Snow and adolescence are the only problems that disappear if you ignore them long enough. Earl Wilson

Snow and adolescence are the only problems that disappear if you ignore them long enough. Earl Wilson Snow and adolescence are the only problems that disappear if you ignore them long enough. Earl Wilson Notices: HW1 is on-line now and due next Tuesday. Reading: Chapters 3 and 1 Stars are exceptionally

More information

Modern Astronomy Review #1

Modern Astronomy Review #1 Modern Astronomy Review #1 1. The red-shift of light from distant galaxies provides evidence that the universe is (1) shrinking, only (3) shrinking and expanding in a cyclic pattern (2) expanding, only

More information

Michael Seeds Dana Backman. Chapter 9 The Family of Stars

Michael Seeds Dana Backman. Chapter 9 The Family of Stars Michael Seeds Dana Backman Chapter 9 The Family of Stars [Love] is the star to every wandering bark, Whose worth s unknown, although his height be taken. WILLIAM SHAKESPEARE Sonnet 116 Shakespeare compared

More information

Astronomy 210 Spring 2017: Quiz 5 Question Packet 1. can: 2. An electron moving between energy levels

Astronomy 210 Spring 2017: Quiz 5 Question Packet 1. can: 2. An electron moving between energy levels Permitted energy levels Astronomy 210 Spring 2017: Quiz 5 Question Packet 1 1. An electron in energy level 1 2 can: (A) only emit a photon. (B) only absorb a photon. (C) either emit, or absorb a photon.

More information

Get ready for quiz # 5! Get out a ½ sheet and Calculator

Get ready for quiz # 5! Get out a ½ sheet and Calculator Get ready for quiz # 5! Get out a ½ sheet and Calculator The above image shows the solar eclipse earlier this month as covered and uncovered by several different solar observatories. The innermost image

More information

Chapter 11 Surveying the Stars

Chapter 11 Surveying the Stars Chapter 11 Surveying the Stars Luminosity Luminosity: Rate of energy emitted by star every second. Apparent brightness (flux): Amount of energy passing through every second per unit area. Luninosity =

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 Look over Chapter 15. Good things to Know. Triangulation

ASTR Look over Chapter 15. Good things to Know. Triangulation ASTR 1020 Look over Chapter 15 Good things to Know Triangulation Parallax Parsecs Absolute Visual Magnitude Distance Modulus Luminosity Balmer Lines Spectral Classes Hertzsprung-Russell (HR) diagram Main

More information

HW 5 posted. Deadline: * Monday 3.00 PM * -- Tip from the coach: Do it earlier, as practice for mid term (it covers only parts included in exam).

HW 5 posted. Deadline: * Monday 3.00 PM * -- Tip from the coach: Do it earlier, as practice for mid term (it covers only parts included in exam). Admin HW 5 posted. Deadline: * Monday 3.00 PM * -- Tip from the coach: Do it earlier, as practice for mid term (it covers only parts included in exam). Lab Wednesday/Thursday -- Spectra http://jonsundqvist.com/phys133/labs.html

More information

Instructions. Students will underline the portions of the PowerPoint that are underlined.

Instructions. Students will underline the portions of the PowerPoint that are underlined. STARS Instructions Students will underline the portions of the PowerPoint that are underlined. Nuclear Furnace 1. A star is like a gigantic nuclear furnace. 2. The nuclear reactions inside convert hydrogen

More information

Announcements. Office hours this Tuesday will be 1-2 pm.

Announcements. Office hours this Tuesday will be 1-2 pm. Announcements Scores for first exam on ICON The average was 53.4 or 67%. The curve is A:80-68, B:64-56, C:52-40, D:36-32, F < 30. Material for problem about Kepler satellite was not adequately covered,

More information

A1101, Lab 5: The Hertzsprung- Russell Diagram Laboratory Worksheet

A1101, Lab 5: The Hertzsprung- Russell Diagram Laboratory Worksheet Student Name: Lab TA Name: A1101, Lab 5: The Hertzsprung- Russell Diagram Laboratory Worksheet One of the most basic physical properties of a star is its luminosity, the rate at which it radiates energy

More information