Chapter 6. Atoms and Starlight

Size: px
Start display at page:

Download "Chapter 6. Atoms and Starlight"

Transcription

1 Chapter 6 Atoms and Starlight

2 What is light?

3

4 Light is an electromagnetic wave.

5 Wavelength and Frequency wavelength frequency = speed of light = constant

6 Particles of Light Particles of light are called photons. Each photon has a wavelength and a frequency. The energy of a photon depends on its frequency.

7 The Amazing Power of Starlight Just by analyzing the light received from a star, astronomers can retrieve information about a star s 1. Total energy output 2. Surface temperature 3. Radius 4. Chemical composition 5. Velocity relative to Earth 6. Rotation period

8 Spectra of stars are more complicated than pure blackbody spectra. Light and Matter characteristic lines, called absorption lines. To understand those lines, we need to understand atomic structure and the interactions between light and atoms.

9 Atomic Structure An atom consists of an atomic nucleus (protons and neutrons) and a cloud of electrons surrounding it. Almost all of the mass is contained in the nucleus, while almost all of the space is occupied by the electron cloud.

10 If you could fill a teaspoon just with material as dense as the matter in an atomic nucleus, it would weigh ~ 2 billion tons!!

11 Different Kinds of Atoms The kind of atom depends on the number of protons in the nucleus. Most abundant: Hydrogen (H), with one proton (+ 1 electron). Next: Helium (He), with 2 protons (and 2 neutrons + 2 el.). Different numbers of neutrons different isotopes Helium 4

12 Electron Orbits Electron orbits in the electron cloud are restricted to very specific radii and energies. These characteristic electron energies are different for each individual element. r 3, E 3 r 2, E 2 r 1, E 1

13 Atomic Transitions An electron can be kicked into a higher orbit when it absorbs a photon with exactly the right energy. E ph = E 3 E 1 E ph = E 4 E 1 The photon is absorbed, and the electron is in an excited state. Wrong energy (Remember that E ph = h*f) All other photons pass by the atom unabsorbed.

14 Chemical Fingerprints Downward transitions produce a unique pattern of emission lines.

15 Chemical Fingerprints Because those atoms can absorb photons with those same energies, upward transitions produce a pattern of absorption lines at the same wavelengths. Production of Absorption Lines

16 Chemical Fingerprints Each type of atom has a unique spectral fingerprint.

17 Chemical Fingerprints Observing the fingerprints in a spectrum tells us which kinds of atoms are present.

18 Example: Solar Spectrum

19 Color and Temperature Stars appear in different colors, from blue (like Rigel) via green / yellow (like our sun) to red (like Betelgeuze). Orion Betelgeuze These colors tell us about the star s temperature. Rigel

20 Blackbody Radiation The light from a star is usually concentrated in a rather narrow range of wavelengths. The spectrum of a star s light is approximately a thermal spectrum called Blackbody Spectrum. A perfect blackbody emitter would not reflect any radiation. Thus the name Blackbody.

21 Two Laws of Blackbody Radiation 1. The hotter an object is, the more luminous it is. 2. The peak of the blackbody spectrum shifts towards shorter wavelengths when the temperature increases.

22 Kirchhoff s Laws of Radiation 1. A solid, liquid, or dense gas excited to emit light will radiate at all wavelengths and thus produce a continuous spectrum.

23 Kirchhoff s Laws of Radiation 2. If light comprising a continuous spectrum passes through a cool, low-density gas, the result will be an absorption spectrum. Light excites electrons in atoms to higher energy states Frequencies corresponding to the transition energies are absorbed from the continuous spectrum..

24 Kirchhoff s Laws of Radiation 3. A low-density gas excited to emit light will do so at specific wavelengths and thus produce an emission spectrum. Light excites electrons in atoms to higher energy states Transition back to lower states emits light at specific frequencies

25 The Spectra of Stars Inner, dense layers of a star produce a continuous (blackbody) spectrum. Cooler surface layers absorb light at specific frequencies. => Spectra of stars are absorption spectra.

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

27 The Balmer Lines n = 1 Transitions from 2 nd to higher levels of hydrogen H a H b H g The only hydrogen lines in the visible wavelength range. 2 nd to 3 rd level = H a (Balmer alpha line) 2 nd to 4 th level = H b (Balmer beta line)

28 Absorption spectrum dominated by Balmer lines Modern spectra are usually recorded digitally and represented as plots of intensity vs. wavelength.

29 Emission nebula, dominated by the red Ha line

30 The Balmer Thermometer Balmer line strength is sensitive to temperature: Most hydrogen atoms are ionized => weak Balmer lines Almost all hydrogen atoms in the ground state (electrons in the n = 1 orbit) => few transitions from n = 2 => weak Balmer lines

31 Measuring the Temperatures of Stars Comparing line strengths, we can measure a star s surface temperature!

32 Temperature Spectral Classification of Stars Different types of stars show different characteristic sets of absorption lines.

33 Spectral Classification of Stars Mnemonics to remember the spectral sequence: Oh Oh Only Be Boy, Bad A An Astronomers Fine F Forget Girl/Guy Grade Generally Kiss Kills Known Me Me Mnemonics

34 Stellar spectra O B A F G K M Surface temperature

35 The Composition of Stars From the relative strength of absorption lines (carefully accounting for their temperature dependence), one can infer the composition of stars.

36 Infrared spectra of stars Major differences appear in the infrared spectra of cool stars (M stars T, L dwarfs).

37

38 The Doppler Effect The light of a moving source is blue/red shifted by Dl/l 0 = v r /c Blue Shift (to higher frequencies) v r Red Shift (to lower frequencies) l 0 = actual wavelength emitted by the source Dl = Wavelength change due to Doppler effect v r = radial velocity

39 Measuring the Shift Stationary Moving Away Away Faster Moving Toward Toward Faster We generally measure the Doppler effect from shifts in the wavelengths of spectral lines.

40 Example: Earth s orbital motion around the sun causes a radial velocity towards (or away from) any star.

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

Light and Atoms

Light and Atoms Light and Atoms ASTR 170 2010 S1 Daniel Zucker E7A 317 zucker@science.mq.edu.au ASTR170 Introductory Astronomy: II. Light and Atoms 1 Overview We ve looked at telescopes, spectrographs and spectra now

More information

10/31/2018. Chapter 7. Atoms Light and Spectra. Thursday Lab Announcement. Topics For Today s Class Black Body Radiation Laws

10/31/2018. Chapter 7. Atoms Light and Spectra. Thursday Lab Announcement. Topics For Today s Class Black Body Radiation Laws Phys1411 Introductory Astronomy Instructor: Dr. Goderya Chapter 7 Atoms Light and Spectra Thursday Lab Announcement Jonah will start the Lab at 6:00 PM. Two pieces of Glass and HST Lunar Phases Topics

More information

3/26/2018. Atoms Light and Spectra. Topics For Today s Class. Reminder. Topics For Today s Class. The Atom. Phys1403 Stars and Galaxies

3/26/2018. Atoms Light and Spectra. Topics For Today s Class. Reminder. Topics For Today s Class. The Atom. Phys1403 Stars and Galaxies Foundations of Astronomy 13e Seeds Foundations of Astronomy 13e Seeds Phys1403 Stars and Galaxies Instructor: Dr. Goderya Chapter 7 Atoms Light and Spectra Reminder Homework for Chapter 5, 6 and 7 is posted

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

Today. Kirchoff s Laws. Emission and Absorption. Stellar Spectra & Composition. Doppler Effect & Motion. Extrasolar Planets

Today. Kirchoff s Laws. Emission and Absorption. Stellar Spectra & Composition. Doppler Effect & Motion. Extrasolar Planets Today Kirchoff s Laws Emission and Absorption Stellar Spectra & Composition Doppler Effect & Motion Extrasolar Planets Three basic types of spectra Continuous Spectrum Intensity Emission Line Spectrum

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

Temperature and Radiation. What can we learn from light? Temperature, Heat, or Thermal Energy? Kelvin Temperature Scale

Temperature and Radiation. What can we learn from light? Temperature, Heat, or Thermal Energy? Kelvin Temperature Scale What can we learn from light? Temperature Energy Chemical Composition Speed towards or away from us All from the spectrum! Temperature and Radiation Why do different objects give off different forms of

More information

Next quiz: Monday, October 24

Next quiz: Monday, October 24 No homework for Wednesday Read Chapter 8! Next quiz: Monday, October 24 1 Chapter 7 Atoms and Starlight Types of Spectra: Pictorial Some light sources are comprised of all colors (white light). Other light

More information

Chapter 4. Spectroscopy. Dr. Tariq Al-Abdullah

Chapter 4. Spectroscopy. Dr. Tariq Al-Abdullah Chapter 4 Spectroscopy Dr. Tariq Al-Abdullah Learning Goals: 4.1 Spectral Lines 4.2 Atoms and Radiation 4.3 Formation of the Spectral Lines 4.4 Molecules 4.5 Spectral Line Analysis 2 DR. T. AL-ABDULLAH

More information

Chapter 5 Light and Matter: Reading Messages from the Cosmos. What is light? Properties of Waves. Waves. The Electromagnetic Spectrum

Chapter 5 Light and Matter: Reading Messages from the Cosmos. What is light? Properties of Waves. Waves. The Electromagnetic Spectrum Chapter 5 Light and Matter: Reading Messages from the Cosmos What is light? Light is a form of radiant energy Light can act either like a wave or like a particle (photon) Spectrum of the Sun 1 2 Waves

More information

Types of Spectra. How do spectrum lines form? 3/30/09. Electron cloud. Atom. Nucleus

Types of Spectra. How do spectrum lines form? 3/30/09. Electron cloud. Atom. Nucleus The electron should be thought of as a distribution or cloud of probability around the nucleus that on average behave like a point particle on a fixed circular path Types of Spectra How do spectrum lines

More information

Chapter 5 Light and Matter: Reading Messages from the Cosmos. 5.1 Light in Everyday Life. How do we experience light?

Chapter 5 Light and Matter: Reading Messages from the Cosmos. 5.1 Light in Everyday Life. How do we experience light? Chapter 5 Light and Matter: Reading Messages from the Cosmos 5.1 Light in Everyday Life Our goals for learning: How do we experience light? How do light and matter interact? How do we experience light?

More information

Temperature and Radiation. What can we learn from light? Temperature, Heat, or Thermal Energy? Kelvin Temperature Scale

Temperature and Radiation. What can we learn from light? Temperature, Heat, or Thermal Energy? Kelvin Temperature Scale What can we learn from light? Temperature Energy Chemical Composition Speed towards or away from us All from the spectrum! Temperature and Radiation Why do different objects give off different forms of

More information

Chapter 5 Light and Matter: Reading Messages from the Cosmos

Chapter 5 Light and Matter: Reading Messages from the Cosmos Chapter 5 Light and Matter: Reading Messages from the Cosmos 5.1 Light in Everyday Life Our goals for learning How do we experience light? How do light and matter interact? How do we experience light?

More information

AST 105 Intro Astronomy The Solar System. MIDTERM II: Tuesday, April 5 [covering Lectures 10 through 16]

AST 105 Intro Astronomy The Solar System. MIDTERM II: Tuesday, April 5 [covering Lectures 10 through 16] AST 105 Intro Astronomy The Solar System MIDTERM II: Tuesday, April 5 [covering Lectures 10 through 16] REVIEW Light as Information Bearer We can separate light into its different wavelengths (spectrum).

More information

Today. Spectra. Thermal Radiation. Wien s Law. Stefan-Boltzmann Law. Kirchoff s Laws. Emission and Absorption. Spectra & Composition

Today. Spectra. Thermal Radiation. Wien s Law. Stefan-Boltzmann Law. Kirchoff s Laws. Emission and Absorption. Spectra & Composition Today Spectra Thermal Radiation Wien s Law Stefan-Boltzmann Law Kirchoff s Laws Emission and Absorption Spectra & Composition Spectrum Originally, the range of colors obtained by passing sunlight through

More information

Chapter 5 Light and Matter: Reading Messages from the Cosmos. How do we experience light? Colors of Light. How do light and matter interact?

Chapter 5 Light and Matter: Reading Messages from the Cosmos. How do we experience light? Colors of Light. How do light and matter interact? Chapter 5 Light and Matter: Reading Messages from the Cosmos How do we experience light? The warmth of sunlight tells us that light is a form of energy We can measure the amount of energy emitted by a

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

What are the three basic types of spectra?

What are the three basic types of spectra? Learning from Light Our goals for learning What are the three basic types of spectra? How does light tell us what things are made of? How does light tell us the temperatures of planets and stars? How do

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

Chapter 4 Spectroscopy

Chapter 4 Spectroscopy Chapter 4 Spectroscopy The beautiful visible spectrum of the star Procyon is shown here from red to blue, interrupted by hundreds of dark lines caused by the absorption of light in the hot star s cooler

More information

A100H Exploring the Universe: The interaction of light and matter. Martin D. Weinberg UMass Astronomy

A100H Exploring the Universe: The interaction of light and matter. Martin D. Weinberg UMass Astronomy A100H Exploring the Universe: The interaction of light and matter Martin D. Weinberg UMass Astronomy astron100h-mdw@courses.umass.edu February 11, 2016 Read: Chap 5 02/11/16 slide 1 Exam #1: Thu 18 Feb

More information

Light and Matter: Reading Messages from the Cosmos. White light is made up of many different colors. Interactions of Light with Matter

Light and Matter: Reading Messages from the Cosmos. White light is made up of many different colors. Interactions of Light with Matter Chapter 5 Lecture The Cosmic Perspective Light and Matter: Reading Messages from the Cosmos 5.1 Light in Everyday Life Our goals for learning: How do we experience light? How do light and matter interact?

More information

Chapter 5: Light and Matter: Reading Messages from the Cosmos

Chapter 5: Light and Matter: Reading Messages from the Cosmos Chapter 5 Lecture Chapter 5: Light and Matter: Reading Messages from the Cosmos Light and Matter: Reading Messages from the Cosmos 5.1 Light in Everyday Life Our goals for learning: How do we experience

More information

Light and Atoms. ASTR 1120 General Astronomy: Stars & Galaxies. ASTR 1120 General Astronomy: Stars & Galaxies !ATH REVIEW: #AST CLASS: "OMEWORK #1

Light and Atoms. ASTR 1120 General Astronomy: Stars & Galaxies. ASTR 1120 General Astronomy: Stars & Galaxies !ATH REVIEW: #AST CLASS: OMEWORK #1 ASTR 1120 General Astronomy: Stars & Galaxies!ATH REVIEW: Tonight, 5-6pm, in RAMY N1B23 "OMEWORK #1 -Due THU, Sept. 10, by 5pm, on Mastering Astronomy CLASS RECORDED STARTED - INFO WILL BE POSTED on CULEARN

More information

How does your eye form an Refraction

How does your eye form an Refraction Astronomical Instruments Eyes and Cameras: Everyday Light Sensors How does your eye form an image? How do we record images? How does your eye form an image? Refraction Refraction is the bending of light

More information

Pictures of Atoms. 48 iron atoms on copper Made with a scanning tunnelling microscope

Pictures of Atoms. 48 iron atoms on copper Made with a scanning tunnelling microscope A-toms = Not Cutable Democritus 420BC popularized the theory matter was made of Atoms: Too small to be seen Indivisible Surrounded by a void Solid No internal structure Pictures of Atoms 48 iron atoms

More information

Chapter 5 Light and Matter

Chapter 5 Light and Matter Chapter 5 Light and Matter Stars and galaxies are too far for us to send a spacecraft or to visit (in our lifetimes). All we can receive from them is light But there is much we can learn (composition,

More information

Lecture Outline: Spectroscopy (Ch. 4)

Lecture Outline: Spectroscopy (Ch. 4) Lecture Outline: Spectroscopy (Ch. 4) NOTE: These are just an outline of the lectures and a guide to the textbook. The material will be covered in more detail in class. We will cover nearly all of the

More information

Lecture5PracticeQuiz.txt

Lecture5PracticeQuiz.txt TAKEN FROM HORIZONS 7TH EDITION CHAPTER 6 TUTORIAL QUIZ 1. The difference between radiation and sound is that a. radiation exhibits the Doppler effect, whereas sound does not. b. radiation travels much

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

LECTURE 23 SPECTROSCOPY AND ATOMIC MODELS. Instructor: Kazumi Tolich

LECTURE 23 SPECTROSCOPY AND ATOMIC MODELS. Instructor: Kazumi Tolich LECTURE 23 SPECTROSCOPY AND ATOMIC MODELS Instructor: Kazumi Tolich Lecture 23 2 29.1 Spectroscopy 29.2 Atoms The first nuclear physics experiment Using the nuclear model 29.3 Bohr s model of atomic quantization

More information

ASTRO Fall 2012 LAB #7: The Electromagnetic Spectrum

ASTRO Fall 2012 LAB #7: The Electromagnetic Spectrum ASTRO 1050 - Fall 2012 LAB #7: The Electromagnetic Spectrum ABSTRACT Astronomers rely on light to convey almost all of the information we have on distant astronomical objects. In addition to measuring

More information

From Last Time Pearson Education, Inc.

From Last Time Pearson Education, Inc. From Last Time Light: Absorption, Emission, Transmission, Reflection, and Scattering c=λ x f E=h x f Light (electromagnetic radiation) extends from gamma rays (high E, high f, small λ) to radio waves (small

More information

Next Homework Due Oct. 9. Coming up: The Sun (Chapter 10)

Next Homework Due Oct. 9. Coming up: The Sun (Chapter 10) Today Summary of Chapter 3: Light All of Chapter 4: Spectra & Atoms Optional: Ast. Toolbox 4-2 Optional: Stephan-Boltzmann Law Next Homework Due Oct. 9 Coming up: The Sun (Chapter 10) Resolving Power:

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

What is LIGHT? Reading Question

What is LIGHT? Reading Question Reading Question What is LIGHT? A. Light is a wave, like sound only much faster. B. Light is like little particles. Each one is a photon. C. Light is the absence of dark. D. A kind of energy we model with

More information

hf = E 1 - E 2 hc = E 1 - E 2 λ FXA 2008 Candidates should be able to : EMISSION LINE SPECTRA

hf = E 1 - E 2 hc = E 1 - E 2 λ FXA 2008 Candidates should be able to : EMISSION LINE SPECTRA 1 Candidates should be able to : EMISSION LINE SPECTRA Explain how spectral lines are evidence for the existence of discrete energy levels in isolated atoms (i.e. in a gas discharge lamp). Describe the

More information

Next quiz: Monday, October 24 Chp. 6 (nothing on telescopes) Chp. 7 a few problems from previous material cough, cough, gravity, cough, cough...

Next quiz: Monday, October 24 Chp. 6 (nothing on telescopes) Chp. 7 a few problems from previous material cough, cough, gravity, cough, cough... Next quiz: Monday, October 24 Chp. 6 (nothing on telescopes) Chp. 7 a few problems from previous material cough, cough, gravity, cough, cough... 1 Chapter 7 Atoms and Starlight Kirchhoff s Laws of Radiation

More information

The Nature of Light. Chapter Five

The Nature of Light. Chapter Five The Nature of Light Chapter Five Guiding Questions 1. How fast does light travel? How can this speed be measured? 2. Why do we think light is a wave? What kind of wave is it? 3. How is the light from an

More information

HOMEWORK - Chapter 4 Spectroscopy

HOMEWORK - Chapter 4 Spectroscopy Astronomy 10 HOMEWORK - Chapter 4 Spectroscopy 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

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

Telescopes have Three Powers

Telescopes have Three Powers Telescopes have Three Powers 1. Light Gathering Power: The ability to collect light 2. Resolving Power: The ability to see fine details 3. Magnifying Power: The ability to make objects look bigger Pizzas!!!

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

Atoms and Star Formation

Atoms and Star Formation Atoms and Star Formation What are the characteristics of an atom? Atoms have a nucleus of protons and neutrons about which electrons orbit. neutrons protons electrons 0 charge +1 charge 1 charge 1.67 x

More information

Astronomy 1143 Quiz 2 Review

Astronomy 1143 Quiz 2 Review Astronomy 1143 Quiz 2 Review Prof. Pradhan October 1, 2018 Light 1. What is light? Light is electromagnetic energy It is both a particle (photon) and a wave 2. How is light created and what can light interact

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

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

Light III The Atom & Spectra. February 12, 2012

Light III The Atom & Spectra. February 12, 2012 Light III The Atom & Spectra February 12, 2012 Average: 65 20 Test 1 15 10 5 0 0-50 50-60 60-70 70-80 80-90 90-100 Takeaway Message: YOU NEED TO STUDY MORE you need to come to class EVERY DAY (TPS questions

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 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

! Finish Ch. 4.! Start Chapter 10: The Sun.! Homework Due: Oct. 10

! Finish Ch. 4.! Start Chapter 10: The Sun.! Homework Due: Oct. 10 ! Finish Ch. 4! Start Chapter 10: The Sun! Homework Due: Oct. 10 A Spectral Mystery Mystery: Why do so many stars have an absorption spectrum (with certain colors missing)? The atoms that make up these

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

LIGHT. Question. Until very recently, the study of ALL astronomical objects, outside of the Solar System, has been with telescopes observing light.

LIGHT. Question. Until very recently, the study of ALL astronomical objects, outside of the Solar System, has been with telescopes observing light. LIGHT Question Until very recently, the study of ALL astronomical objects, outside of the Solar System, has been with telescopes observing light. What kind of information can we get from light? 1 Light

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

Announcement Test 2. is coming up on Mar 19. Start preparing! This test will cover the classes from Feb 27 - Mar points, scantron, 1 hr.

Announcement Test 2. is coming up on Mar 19. Start preparing! This test will cover the classes from Feb 27 - Mar points, scantron, 1 hr. Announcement Test 2 is coming up on Mar 19. Start preparing! This test will cover the classes from Feb 27 - Mar 14. 50 points, scantron, 1 hr. 1 AST 103 Light, Atoms, and Spectra (continued) Analyzing

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

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

Susan Cartwright Our Evolving Universe 1

Susan Cartwright Our Evolving Universe 1 Atoms and Starlight Why do the stars shine? planets shine by reflected sunlight but what generates the Sun s light? What does starlight tell us about the stars? their temperature their chemical composition

More information

Astronomy The Nature of Light

Astronomy The Nature of Light Astronomy The Nature of Light A. Dayle Hancock adhancock@wm.edu Small 239 Office hours: MTWR 10-11am Measuring the speed of light Light is an electromagnetic wave The relationship between Light and temperature

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

Topics Covered in Chapter. Light and Other Electromagnetic Radiation. A Subatomic Interlude II. A Subatomic Interlude. A Subatomic Interlude III

Topics Covered in Chapter. Light and Other Electromagnetic Radiation. A Subatomic Interlude II. A Subatomic Interlude. A Subatomic Interlude III Light and Other Electromagnetic Radiation Topics Covered in Chapter 1.Structure of Atoms 2.Origins of Electromagnetic Radiation 3.Objects with Different Temperature and their Electromagnetic Radiation

More information

Light and Other Electromagnetic Radiation

Light and Other Electromagnetic Radiation Light and Other Electromagnetic Radiation 1 Topics Covered in Chapter 1.Structure of Atoms 2.Origins of Electromagnetic Radiation 3.Objects with Different Temperature and their Electromagnetic Radiation

More information

How does your eye form an Refraction

How does your eye form an Refraction Astronomical Instruments and : Everyday Light Sensors How does your eye form an image? How do we record images? How does your eye form an image? Refraction Refraction is the of light Eye uses refraction

More information

Chapter 28. Atomic Physics

Chapter 28. Atomic Physics Chapter 28 Atomic Physics Sir Joseph John Thomson J. J. Thomson 1856-1940 Discovered the electron Did extensive work with cathode ray deflections 1906 Nobel Prize for discovery of electron Early Models

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

Next Homework Due March 6. Coming up: The Sun (Chapter 10)

Next Homework Due March 6. Coming up: The Sun (Chapter 10) Today Summary of Chapter 3: Light All of Chapter 4: Spectra & Atoms Optional: Ast. Toolbox 4-2 Optional: Stephan-Boltzmann Law Next Homework Due March 6 Coming up: The Sun (Chapter 10) Extra Credit Astro-talks:

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

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

Hydrogen Lines. What can we learn from light? Spectral Classification. Visible Hydrogen Spectrum Lines: Series. Actual Spectrum from SDSS

Hydrogen Lines. What can we learn from light? Spectral Classification. Visible Hydrogen Spectrum Lines: Series. Actual Spectrum from SDSS What can we learn from light? Hydrogen Lines Temperature Energy Chemical Composition Speed towards or away from us All from the! Lower E, Lower f, λ Visible! Higher E, Higher f, λ Visible Hydrogen Spectrum

More information

EVOLUTION OF STARS HERTZSPRUNG-RUSSELL DIAGRAM

EVOLUTION OF STARS HERTZSPRUNG-RUSSELL DIAGRAM VISUAL PHYSICS ONLINE EVOLUTION OF STARS HERTZSPRUNG-RUSSELL DIAGRAM The total power radiated by a star is called its intrinsic luminosity L (luminosity). The apparent brightness (apparent luminosity)

More information

ASTRONOMY 103: THE EVOLVING UNIVERSE. Lecture 4 COSMIC CHEMISTRY Substitute Lecturer: Paul Sell

ASTRONOMY 103: THE EVOLVING UNIVERSE. Lecture 4 COSMIC CHEMISTRY Substitute Lecturer: Paul Sell ASTRONOMY 103: THE EVOLVING UNIVERSE Lecture 4 COSMIC CHEMISTRY Substitute Lecturer: Paul Sell Two Blackbody Trends 1. Wein s (Veen s) Law λp 1 / T or λp = 2900 / T (λp is the peak wavelength in micrometers

More information

CHAPTER 29: STARS BELL RINGER:

CHAPTER 29: STARS BELL RINGER: CHAPTER 29: STARS BELL RINGER: Where does the energy of the Sun come from? Compare the size of the Sun to the size of Earth. 1 CHAPTER 29.1: THE SUN What are the properties of the Sun? What are the layers

More information

Lecture 16 Atomic Spectra Doppler Effect October 29, 2018

Lecture 16 Atomic Spectra Doppler Effect October 29, 2018 Lecture 16 Atomic Spectra Doppler Effect October 29, 2018 1 4 Comet 96P/Machholz October 2017 Comet 96P does this every 5.24 years. It is a short period comet that experiences frequent blasts of solar

More information

Discussion Review Test #2. Units 12-19: (1) (2) (3) (4) (5) (6)

Discussion Review Test #2. Units 12-19: (1) (2) (3) (4) (5) (6) Discussion Review Test #2 Units 12-19: (1) (2) (3) (4) (5) (6) (7) (8) (9) Galileo used his observations of the changing phases of Venus to demonstrate that a. the sun moves around the Earth b. the universe

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

Which property of a star would not change if we could observe it from twice as far away? a) Angular size b) Color c) Flux d) Parallax e) Proper Motion

Which property of a star would not change if we could observe it from twice as far away? a) Angular size b) Color c) Flux d) Parallax e) Proper Motion Exam #1 is in class next monday 25 multiple-choice questions 50 minutes Similar to questions asked in class Review sheet to be posted this week. We will have two 1-hour review sessions Friday 5-6pm (with

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

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

Light & Atoms. Electromagnetic [EM] Waves. Light and several other forms of radiation are called electromagnetic waves or electromagnetic radiation.

Light & Atoms. Electromagnetic [EM] Waves. Light and several other forms of radiation are called electromagnetic waves or electromagnetic radiation. Light & Atoms Electromagnetic [EM] Waves Light and several other forms of radiation are called electromagnetic waves or electromagnetic radiation. These have both and electric part and a magnetic part

More information

NSCI 314 LIFE IN THE COSMOS

NSCI 314 LIFE IN THE COSMOS NSCI 314 LIFE IN THE COSMOS 2 BASIC ASTRONOMY, AND STARS AND THEIR EVOLUTION Dr. Karen Kolehmainen Department of Physics CSUSB COURSE WEBPAGE: http://physics.csusb.edu/~karen MOTIONS IN THE SOLAR SYSTEM

More information

Atoms and Spectra October 8th, 2013

Atoms and Spectra October 8th, 2013 Atoms and Spectra October 8th, 2013 Announcements Second writing assignment due two weeks from today (again, on a news item of your choice). Be sure to make plans to visit one of the open observing nights

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

9/19/ Basic Properties of Light and Matter. Chapter 5: Light: The Cosmic Messenger. What is light? Lecture Outline

9/19/ Basic Properties of Light and Matter. Chapter 5: Light: The Cosmic Messenger. What is light? Lecture Outline Lecture Outline 5.1 Basic Properties of Light and Matter Chapter 5: Light: The Cosmic Messenger Our goals for learning: What is light? What is matter? How do light and matter interact? What is light? Light

More information

ASTR-1010: Astronomy I Course Notes Section IV

ASTR-1010: Astronomy I Course Notes Section IV ASTR-1010: Astronomy I Course Notes Section IV Dr. Donald G. Luttermoser Department of Physics and Astronomy East Tennessee State University Edition 2.0 Abstract These class notes are designed for use

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

Observational Astronomy - Lecture 8 Stars I - Distances, Magnitudes, Spectra, HR Diagram

Observational Astronomy - Lecture 8 Stars I - Distances, Magnitudes, Spectra, HR Diagram Observational Astronomy - Lecture 8 Stars I - Distances, Magnitudes, Spectra, HR Diagram Craig Lage New York University - Department of Physics craig.lage@nyu.edu April 7, 2014 1 / 36 JPL Horizons Database.

More information

Number of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc)

Number of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc) THE MILKY WAY GALAXY Type: Spiral galaxy composed of a highly flattened disk and a central elliptical bulge. The disk is about 100,000 light years (30kpc) in diameter. The term spiral arises from the external

More information

Prof. Jeff Kenney Class 5 June 1, 2018

Prof. Jeff Kenney Class 5 June 1, 2018 www.astro.yale.edu/astro120 Prof. Jeff Kenney Class 5 June 1, 2018 to understand how we know stuff about the universe we need to understand: 1. the spectral analysis of light 2. how light interacts with

More information

Light and Matter(LC)

Light and Matter(LC) Light and Matter(LC) Every astronomy book that I ve seen has at least one chapter dedicated to the physics of light. Why are astronomers so interested in light? Everything* that we know about Astronomical

More information

Chapter 5 Light: The Cosmic Messenger. Copyright 2012 Pearson Education, Inc.

Chapter 5 Light: The Cosmic Messenger. Copyright 2012 Pearson Education, Inc. Chapter 5 Light: The Cosmic Messenger 5.1 Basic Properties of Light and Matter Our goals for learning: What is light? What is matter? How do light and matter interact? What is light? Light is an electromagnetic

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

Activity: Cosmic Colors and Spectroscopy

Activity: Cosmic Colors and Spectroscopy 1 Activity: Cosmic Colors and Spectroscopy Background: The energy of a photon of light depends on the wavelength (frequency) of the light higher frequency f = higher energy E = shorter wavelength λ) red

More information

Lecture #8. Light-matter interaction. Kirchoff s laws

Lecture #8. Light-matter interaction. Kirchoff s laws 1 Lecture #8 Light-matter interaction Kirchoff s laws 2 Line emission/absorption Atoms: release and absorb photons with a predefined set of energies (discrete). The number of protons determine the chemical

More information

The atom cont. +Investigating EM radiation

The atom cont. +Investigating EM radiation The atom cont. +Investigating EM radiation Announcements: First midterm is 7:30pm on Sept 26, 2013 Will post a past midterm exam from 2011 today. We are covering Chapter 3 today. (Started on Wednesday)

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

aka Light Properties of Light are simultaneously

aka Light Properties of Light are simultaneously Today Interaction of Light with Matter Thermal Radiation Kirchhoff s Laws aka Light Properties of Light are simultaneously wave-like AND particle-like Sometimes it behaves like ripples on a pond (waves).

More information

Deducing Temperatures and Luminosities of Stars (and other objects ) Electromagnetic Fields. Sinusoidal Fields

Deducing Temperatures and Luminosities of Stars (and other objects ) Electromagnetic Fields. Sinusoidal Fields Deducing Temperatures and Luminosities of Stars (and other objects ) Review: Electromagnetic Radiation Gamma Rays X Rays Ultraviolet (UV) Visible Light Infrared (IR) Increasing energy Microwaves Radio

More information

Newton s Laws of Motion

Newton s Laws of Motion Newton s Laws of Motion #1: A body continues at rest or in uniform motion in a straight line unless acted upon by a force. Why doesn t the soccer ball move on its own? What causes a soccer ball to roll

More information