Chapter 9: Measuring the Stars

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Chapter 9: Measuring the Stars"

Transcription

1 Chapter 9: Measuring the Stars About (100,000,000,000) stars in a galaxy; also about galaxies in the universe Stars have various major characteristics, the majority of which fall into several simple types. These are related to their stages of the life cycles, just like people. The INITIAL MASS is a very important aspect that determines a star s future:

2

3 Life Sequence of a Star Life Cycles of the Hot and Massive Young stellar objects (YSOs) The normal life cycle of stars with mass about that of the Sun is as follows: 1) Gas and dust in a cool nebula condense, forming a young stellar object (YSO) 2) Shrinking, the YSO dispels its remaining birth cloud, and its hydrogen fire ignites 3) As the hydrogen burns steadily, the star joins the main sequence. 4) When the star uses up all of the hydrogen in its core, the hydrogen in the shell (a larger region around the core) ignites. 5) The energy released by the burning of the hydrogen shell makes the star brighter and it expands, which makes the surface larger, cooler, and redder. The star has become a red giant. 6) Stellar winds blowing off the star gradually expel its outer layers, which form planetary nebula around the remaining hot stellar core. 7) The nebula expands and dissipates into space, leaving just the hot core. 8) The core, now a white dwarf star, cools and fades forever. Note that after most H is converted to He in the core, the star becomes a Red Giant. If the star is much more massive, it burns elements in the core all the way up to Iron (Fe), and becomes a super Red Giant, then explodes as a SUPERNOVA, and the inner region forms a neutron star or black hole. The Sun will last about 10 billion years, but a much more massive star may last only a few million years after its birth. Less massive starts may be red dwarfs, and remain so for as very long time. RULE: the bigger (more massive) the star, the shorter is its lifetime.

4 Part II: Chapter 9 This chapter is heavy on the various methods used to measure cosmic distances. This has been a major and constant theme in astronomy, and slowly a great variety of methods have ben found to extend accurate measurements to objects at ever greater distances (see illustration below).

5 PARALAX: The oldest method is parallax which has already been mentioned in past chapters. This is how humans have a since of distance: two eyes separated by several centimeters. Our brain gets information from both eyes, and using tis separation of the eyes and the different respective from both eyes gets an estimate of how far away objects are located. All done by the brain automatically and subconsciously. Inverse Square Law: As light spreads out from a source its intensity decreases according to the inverse-square law, 1/r 2. Thus when we observe and object in the night sky there are: the apparent magnitude and the absolute magnitude The apparent magnitude is just what we measure, where as the absolute magnitude is the intensity that the star is actually emitting. To know this, we must know the distance to the star. Ancient Greeks categorized the brightest objects as magnitude 1, the next group as magnitude 2 etc. BUT this was by the naked eye, and thus not very sensitive to measuring the actual amount of light being received. Based on good energy measurements to days, and still using the old system: Sun, -26.7; full moon, -12.5; Venus, -4.4; Sirius, -1.5; Alpha Centauri, 0; Polaris, 2.5; naked-eye limit, 6; binocular limit, 10; 1-meter telescope, 18-20; Hubble, Keck, 30) See book for Table (p. 153).

6 STELLAR TEMPERATURE: It is also possible to record the spectra of a star, and from this to estimate the absolute magnitude at the surface. By knowing BOTH th absolute magnitude and relative magnetite it is possible to calculate the distance. Only the LARGEST objects that are not too far away an be measured by parallax, like their size.

7 Hertzsprung-Russel (HR) diagram: Estimating stellar mass by observing interaction with some nearby object:

8 Diagramming Star Color, Brightness, Mass Based on OBSERVATIONS can make a graph: Vertical axis = Luminosity, amount of energy (can also use the Magnitude system) Horizontal axis = Star spectral type (COLOR; = temperature) Called Color-Luminosity diagram or Hertzsprung-Russell (HR) Diagram The Absolute Magnitude was derived from the ancient system of Greek astronomer Hipparchus ( B.C.). He set the brightest star in the night sky as 1, and then next as 2, and so on Later when it became possible to measure more accurately, some stars set at 0, and even negative numbers. Today the Absolute Magnitude is defined as the Apparent Magnitude if that star were located at 32.6 light-years from Earth. In this system the Sun is 4.8. Spectral type: What color is my star? The spectral type represents the spectrum of a star. Based on blackbody curves (below), can get information about the star temperature Early designated as (OBAFGKM = Oh Be A Fine Girl, Kiss Me) O is hottest and M is coolest

9 A black body is a perfect absorber and emitter of light. One very rood example is the pupil of your eye, a window of light into your brain. Evolution found that this black spot is excellent for getting the most light inside. * A heated body also emits radiation with a black body CONTINUOUS distribution of wavelengths based on temperature. Below illustrates various stars, their color, and blackbody curve.

10 Star light, star bright: Classifying luminosity Each spectral class has subdivisions (not important for us) V is the luminosity class; Sun is designated as V (5) ; Roman numeral Super-giants are I and II, and giants are III The brighter they burn, the bigger they swell: Mass determines class GREATER MASS means a hotter star with faster core burning Two factors determine a star s brightness: temperature and surface area Brighter star has more surface area Also, the hotter the star, the more energy is released per area of surface (E = T 4 ) Most stars are located on the diagonal band, called Main Sequence There is also a RED GIANT SEQUENCE in the upper right Supergiant; blue supergiant sequence also, above and to left Bottom left is white dwarf cluster or sequence; these dwarfs move to the right as the cool, become dimmer and change to emit longer wavelengths

11 Spectra of stars After light is emitted from the photosphere with a blackbody spectra associated with a certain temperature, it passes through the outer atmosphere of the star, which can be hundreds of thousands of kilometers thick. While propagating through this region it interacts with the various atoms existing there. Each type of atom (hydrogen, helium, carbon, cesium etc. etc.) has very specific energy levels. Those wavelengths that match these energy levels will be absorbed, while causing electrons to jump to higher levels. This action produced absorption spectra, which can be seen as black vertical absorption lines on the continuous blackbody spectra. Hotter stars show strong Hydrogen lines, whereas cooler stars have strong metallic lines.

12

13 Eternal Partners: Binary and Multiple Stars If two or more stars orbit a common center of mass, this system is called binary stars or multiple stars, respectively. Binary stars and Doppler Effect About ½ of all stars are binary Can observe by the Doppler Shift Two stars are binary, but three s a crowd: Multiple stars Sometimes two stars APPEAR to be near each other, but are actually far apart and unrelated. Three stars are unstable; so might be a true binary associated with a third star.

14 Change IS Good: Variable Stars Some stars change in brightness over time Pulsating stars Flare stars Exploding stars Going the distance: Pulsating stars Cepheid variables: period & luminosity related; greater period = greater average brightness; can measure the apparent brightness with time, get the period, and then determine the actual brightness. Distance proportional to 1/r 2 Can be used to look at starts and get distances in far away galaxies

15 Among the major topics in astronomy, and one that has been hugely controversial throughout the history of this field, is how to accurately determine distances to the great variety of objects. Over much time a surprisingly large variety of techniques have come to be understand that cover vastly different distant scales. Below is an illustration of the major techniques now available to astronomers:

16 The name parsec is "an abbreviated form of 'a distance corresponding to a parallax of one arcsecond'." [1] It was coined in 1913 at the suggestion of British astronomer Herbert Hall Turner. A parsec is the distance from the Sun to an astronomical object which has a parallax angle of one arcsecond ( 1 3,600 of a degree). In other words, imagine three straight lines forming a right triangle between the Earth, the Sun and a distant object, as follows: line 1 connects the Earth and the Sun, line 2, perpendicular to the first line, connects the Sun and the object, and line 3 connects the object to the Earth. Now, if the angle at the object between lines 2 and 3 is exactly one arcsecond, then the object's distance from the Sun would be exactly one parsec.

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

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

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

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 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

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

Ch. 10: Star Formation of Planetary Systems. A summary of the process by which our solar system formed, according to the nebular theory.

Ch. 10: Star Formation of Planetary Systems. A summary of the process by which our solar system formed, according to the nebular theory. 1 Ch. 10: Star Formation of Planetary Systems A summary of the process by which our solar system formed, according to the nebular theory. Materials in the solar nebula. 2 3 Temperature differences in the

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

Position 1 Position 2 6 after position 1 Distance between positions 1 and 2 is the Bigger = bigger parallax (Ɵ)

Position 1 Position 2 6 after position 1 Distance between positions 1 and 2 is the Bigger = bigger parallax (Ɵ) STARS CHAPTER 10.1 the solar neighborhood The distances to the nearest stars can be measured using Parallax => the shift of an object relative to some distant background as the observer s point of view

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

How do we know the distance to these stars? The Ping Pong Ball Challenge -Devise a method for determining the height of the ping pong ball above the floor. -You are restricted to the floor. -You can only

More information

The physics of stars. A star begins simply as a roughly spherical ball of (mostly) hydrogen gas, responding only to gravity and it s own pressure.

The physics of stars. A star begins simply as a roughly spherical ball of (mostly) hydrogen gas, responding only to gravity and it s own pressure. Lecture 4 Stars The physics of stars A star begins simply as a roughly spherical ball of (mostly) hydrogen gas, responding only to gravity and it s own pressure. X-ray ultraviolet infrared radio To understand

More information

ASTRONOMY 1 EXAM 3 a Name

ASTRONOMY 1 EXAM 3 a Name ASTRONOMY 1 EXAM 3 a Name Identify Terms - Matching (20 @ 1 point each = 20 pts.) Multiple Choice (25 @ 2 points each = 50 pts.) Essays (choose 3 of 4 @ 10 points each = 30 pt 1.Luminosity D 8.White dwarf

More information

Beyond Our Solar System Chapter 24

Beyond Our Solar System Chapter 24 Beyond Our Solar System Chapter 24 PROPERTIES OF STARS Distance Measuring a star's distance can be very difficult Stellar parallax Used for measuring distance to a star Apparent shift in a star's position

More information

Stars & Galaxies. Chapter 27 Modern Earth Science

Stars & Galaxies. Chapter 27 Modern Earth Science Stars & Galaxies Chapter 27 Modern Earth Science Chapter 27, Section 1 27.1 Characteristics of Stars How do astronomers determine the composition and surface temperature of a star? Composition & Temperature

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

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 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

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 & Galaxies. Chapter 27, Section 1. Composition & Temperature. Chapter 27 Modern Earth Science Characteristics of Stars

Stars & Galaxies. Chapter 27, Section 1. Composition & Temperature. Chapter 27 Modern Earth Science Characteristics of Stars Stars & Galaxies Chapter 27 Modern Earth Science Chapter 27, Section 1 27.1 Characteristics of Stars Composition & Temperature Scientists use the following tools to study stars Telescope Observation Spectral

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

They developed a graph, called the H-R diagram, that relates the temperature of a star to its absolute magnitude.

They developed a graph, called the H-R diagram, that relates the temperature of a star to its absolute magnitude. Ejnar Hertzsprung and Henry Russell noticed that stars with higher temperatures and large sizes also have brighter absolute magnitudes the actual amount of light given off by a star. (also referred to

More information

Galaxies Galore. Types of Galaxies: Star Clusters. Spiral spinning wit arms Elliptical roundish Irregular no set pattern

Galaxies Galore. Types of Galaxies: Star Clusters. Spiral spinning wit arms Elliptical roundish Irregular no set pattern Stars Studying Stars Astronomers use a spectroscope to study the movement of stars Blue shift towards earth Red shift away from earth Change in a wavelength moving toward or away from earth is the Doppler

More information

PHYS103 Sec 901 Hour Exam No. 3 Practice Version 1 Page: 1

PHYS103 Sec 901 Hour Exam No. 3 Practice Version 1 Page: 1 PHYS103 Sec 901 Hour Exam No. 3 Practice Version 1 Page: 1 PHYS103 Sec 901 Hour Exam No. 3 Practice Version 1 Page: 2 1 The HR diagram of a young, open cluster typically shows a. the entire main sequence

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

CHAPTER 28 STARS AND GALAXIES

CHAPTER 28 STARS AND GALAXIES CHAPTER 28 STARS AND GALAXIES 28.1 A CLOSER LOOK AT LIGHT Light is a form of electromagnetic radiation, which is energy that travels in waves. Waves of energy travel at 300,000 km/sec (speed of light Ex:

More information

Types of Stars and the HR diagram

Types of Stars and the HR diagram Types of Stars and the HR diagram Full window version (looks a little nicer). Click button to get back to small framed version with content indexes. This material (and images) is copyrighted! See

More information

Stars and Galaxies 1

Stars and Galaxies 1 Stars and Galaxies 1 Characteristics of Stars 2 Star - body of gases that gives off great amounts of radiant energy as light and heat 3 Most stars look white but are actually different colors Antares -

More information

CONTENT EXPECTATIONS

CONTENT EXPECTATIONS THE SUN & THE STARS CONTENT EXPECTATIONS STARS What are stars? Are they all the same? What makes them different? What is our nearest star? THE SUN Why is it important? provides heat and light that we need

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

PHYS103 Sec 901 Hour Exam No. 3 Page: 1

PHYS103 Sec 901 Hour Exam No. 3 Page: 1 PHYS103 Sec 901 Hour Exam No. 3 Page: 1 PHYS103 Sec 901 Hour Exam No. 3 Page: 2 1 The star alpha-centauri C has moved across the sky by 3853 seconds of arc during the last thousand years - slightly more

More information

PHYS103 Sec 901 Hour Exam No. 3 Page: 1

PHYS103 Sec 901 Hour Exam No. 3 Page: 1 PHYS103 Sec 901 Hour Exam No. 3 Page: 1 PHYS103 Sec 901 Hour Exam No. 3 Page: 2 1 A steady X-ray signal with sudden bursts lasting a few seconds each is probably caused by a. a supermassive star. b. a

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

Prentice Hall EARTH SCIENCE

Prentice Hall EARTH SCIENCE Prentice Hall EARTH SCIENCE Tarbuck Lutgens Chapter 25 Beyond Our Solar System 25.1 Properties of Stars Characteristics of Stars A constellation is an apparent group of stars originally named for mythical

More information

L = 4 d 2 B p. 1. Which outer layer of the Sun has the highest temperature? A) Photosphere B) Corona C) Chromosphere D) Exosphere E) Thermosphere

L = 4 d 2 B p. 1. Which outer layer of the Sun has the highest temperature? A) Photosphere B) Corona C) Chromosphere D) Exosphere E) Thermosphere Fall 2016 Astronomy - Test 3 Test form A Name Do not forget to write your name and fill in the bubbles with your student number, and fill in test form A on the answer sheet. Write your name above as well.

More information

L = 4 d 2 B p. 4. Which of the letters at right corresponds roughly to where one would find a red giant star on the Hertzsprung-Russell diagram?

L = 4 d 2 B p. 4. Which of the letters at right corresponds roughly to where one would find a red giant star on the Hertzsprung-Russell diagram? Fall 2016 Astronomy - Test 3 Test form B Name Do not forget to write your name and fill in the bubbles with your student number, and fill in test form B on the answer sheet. Write your name above as well.

More information

Chapter 28 Stars and Their Characteristics

Chapter 28 Stars and Their Characteristics Chapter 28 Stars and Their Characteristics Origin of the Universe Big Bang Theory about 10-20 bya all matter in the universe existed in a hot dense state about the size of an atom (tiny). That matter sort

More information

ASTRONOMY QUIZ NUMBER 11

ASTRONOMY QUIZ NUMBER 11 ASTRONOMY QUIZ NUMBER. Suppose you measure the parallax of a star and find 0. arsecond. The distance to this star is A) 0 light-years B) 0 parsecs C) 0. light-year D) 0. parsec 2. A star is moving toward

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

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

λ = 650 nm = c = m s 1 f =? c = fλ f = c λ = ( m s 1 ) ( m) = = Hz T = 1 f 4.

λ = 650 nm = c = m s 1 f =? c = fλ f = c λ = ( m s 1 ) ( m) = = Hz T = 1 f 4. Chapter 13 Stars Section 13.1 Astronomical measurements Worked example: Try yourself 13.1.1 CALCULATING THE FREQUENCY AND PERIOD OF LIGHT The speed of light in a vacuum is approximately 3.0 10 8 m s 1.

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

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

Review Questions for the new topics that will be on the Final Exam

Review Questions for the new topics that will be on the Final Exam Review Questions for the new topics that will be on the Final Exam Be sure to review the lecture-tutorials and the material we covered on the first three exams. How does speed differ from velocity? Give

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

8/30/2010. Classifying Stars. Classifying Stars. Classifying Stars

8/30/2010. Classifying Stars. Classifying Stars. Classifying Stars Classifying Stars In the early 1900s, Ejnar Hertzsprung and Henry Russell made some important observations. They noticed that, in general, stars with higher temperatures also have brighter absolute magnitudes.

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

the nature of the universe, galaxies, and stars can be determined by observations over time by using telescopes

the nature of the universe, galaxies, and stars can be determined by observations over time by using telescopes the nature of the universe, galaxies, and stars can be determined by observations over time by using telescopes The spectral lines of stars tell us their approximate composition Remember last year in Physics?

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

Pr P ope p rti t es s of o f St S a t rs

Pr P ope p rti t es s of o f St S a t rs Properties of Stars Distances Parallax ( Triangulation ): - observe object from two separate points - use orbit of the Earth (1 AU) - measure angular shift of object - angle depends on distance to object

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

GALAXIES AND STARS. 2. Which star has a higher luminosity and a lower temperature than the Sun? A Rigel B Barnard s Star C Alpha Centauri D Aldebaran

GALAXIES AND STARS. 2. Which star has a higher luminosity and a lower temperature than the Sun? A Rigel B Barnard s Star C Alpha Centauri D Aldebaran GALAXIES AND STARS 1. Compared with our Sun, the star Betelgeuse is A smaller, hotter, and less luminous B smaller, cooler, and more luminous C larger, hotter, and less luminous D larger, cooler, and more

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

A star is at a distance of 1.3 parsecs, what is its parallax?

A star is at a distance of 1.3 parsecs, what is its parallax? Stars Spectral lines from stars Binaries and the masses of stars Classifying stars: HR diagram Luminosity, radius, and temperature Vogt-Russell theorem Main sequence Evolution on the HR diagram A star

More information

Stars and Galaxies. The Sun and Other Stars

Stars and Galaxies. The Sun and Other Stars CHAPTER 22 Stars and Galaxies LESSON 2 The Sun and Other Stars What do you think? Read the two statements below and decide whether you agree or disagree with them. Place an A in the Before column if you

More information

Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti

Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti INSTRUCTIONS: Please, use the `bubble sheet and a pencil # 2 to answer the exam questions, by marking

More information

Study Guide Chapter 2

Study Guide Chapter 2 Section: Stars Pages 32-38 Study Guide Chapter 2 Circle the letter of the best answer for each question. 1. What do scientists study to learn about stars? a. gravity c. space b. starlight d. colors COLOR

More information

18. Which graph best represents the relationship between the number of sunspots and the amount of magnetic activity in the Sun?

18. Which graph best represents the relationship between the number of sunspots and the amount of magnetic activity in the Sun? 1. Which star has a surface temperature most similar to the surface temperature of Alpha Centauri? A) Polaris B) Betelgeuse C) Procyon B D) Sirius 2. Giant stars have greater luminosity than our sun mainly

More information

Why Do Stars Leave the Main Sequence? Running out of fuel

Why Do Stars Leave the Main Sequence? Running out of fuel Star Deaths Why Do Stars Leave the Main Sequence? Running out of fuel Observing Stellar Evolution by studying Globular Cluster HR diagrams Plot stars in globular clusters in Hertzsprung-Russell diagram

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

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

Chapter Introduction Lesson 1 The View from Earth Lesson 2 The Sun and Other Stars Lesson 3 Evolution of Stars Lesson 4 Galaxies and the Universe

Chapter Introduction Lesson 1 The View from Earth Lesson 2 The Sun and Other Stars Lesson 3 Evolution of Stars Lesson 4 Galaxies and the Universe Chapter Introduction Lesson 1 The View from Earth Lesson 2 The Sun and Other Stars Lesson 3 Evolution of Stars Lesson 4 Galaxies and the Universe Chapter Wrap-Up What makes up the universe and how does

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

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

The Universe and Galaxies

The Universe and Galaxies The Universe and Galaxies 16.1 http://dingo.care-mail.com/cards/flash/5409/galaxy.swf Universe The sum of all matter and energy that exists, that has ever existed, and that will ever exist. We will focus

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

Stellar Evolution and the HertzsprungRussell Diagram 7/14/09. Astronomy 101

Stellar Evolution and the HertzsprungRussell Diagram 7/14/09. Astronomy 101 Stellar Evolution and the HertzsprungRussell Diagram 7/14/09 Astronomy 101 Astronomy Picture of the Day Astronomy 101 Outline for Today Astronomy Picture of the Day News Articles Business Return Lab 5

More information

AST 101 INTRODUCTION TO ASTRONOMY SPRING MIDTERM EXAM 2 TEST VERSION 1 ANSWERS

AST 101 INTRODUCTION TO ASTRONOMY SPRING MIDTERM EXAM 2 TEST VERSION 1 ANSWERS AST 101 INTRODUCTION TO ASTRONOMY SPRING 2008 - MIDTERM EXAM 2 TEST VERSION 1 ANSWERS Multiple Choice. In the blanks provided before each question write the letter for the phrase that best answers the

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

Physics Homework Set 2 Sp 2015

Physics Homework Set 2 Sp 2015 1) A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as 1) A) a reflection nebula. B) a dark patch against a bright background. C) a dark nebula.

More information

Daily Science 04/04/2017

Daily Science 04/04/2017 Daily Science 04/04/2017 Which statement best describes the difference between type A stars and type B stars as shown in the diagram? a. Type A stars burn for a shorter amount of time than type B stars.

More information

Stars and Galaxies. Content Outline for Teaching

Stars and Galaxies. Content Outline for Teaching Section 1 Stars A. Patterns of stars - constellations 1. Ancient cultures used mythology or everyday items to name constellations 2. Modern astronomy studies 88 constellations 3. Some constellations are

More information

ASTRONOMY 1 FINAL EXAM 1 Name

ASTRONOMY 1 FINAL EXAM 1 Name ASTRONOMY 1 FINAL EXAM 1 Name Multiple Choice (2 pts each) 1. Sullivan Star is an F spectral class star that is part of a binary star system. It has a MS lifetime of 5 billion years. Its life will eventually

More information

Characterizing Stars

Characterizing Stars Characterizing Stars 1 Guiding Questions 1. How far away are the stars? 2. What evidence do astronomers have that the Sun is a typical star? 3. What is meant by a first-magnitude or second magnitude star?

More information

Stars Star birth and kinds Elemental furnaces Star death and heavy elements

Stars Star birth and kinds Elemental furnaces Star death and heavy elements Stars Star birth and kinds Elemental furnaces Star death and heavy elements Matter was not uniformly distributed as the universe expanded after the Big Bang. This lumpy universe coalesced under the force

More information

Characterizing Stars. Guiding Questions. Parallax. Careful measurements of the parallaxes of stars reveal their distances

Characterizing Stars. Guiding Questions. Parallax. Careful measurements of the parallaxes of stars reveal their distances Guiding Questions Characterizing Stars 1. How far away are the stars? 2. What evidence do astronomers have that the Sun is a typical star? 3. What is meant by a first-magnitude or second magnitude star?

More information

Stars and Galaxies. Evolution of Stars

Stars and Galaxies. Evolution of Stars chapter 13 3 Stars and Galaxies section 3 Evolution of Stars Before You Read What makes one star different from another? Do you think the Sun is the same as other stars? Write your ideas on the lines below.

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

Chapter 21: Stars Notes

Chapter 21: Stars Notes Branches of Earth Science Chapter 21: Stars Notes Astronomy: The study of planets, stars, and other objects in space. Lithosphere: the land masses of earth o Litho means rock Hydrosphere: waters of the

More information

Properties of Stars. Characteristics of Stars

Properties of Stars. Characteristics of Stars Properties of Stars Characteristics of Stars A constellation is an apparent group of stars originally named for mythical characters. The sky contains 88 constellations. Star Color and Temperature Color

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

Life Cycle of a Star - Activities

Life Cycle of a Star - Activities Name: Class Period: Life Cycle of a Star - Activities A STAR IS BORN STAGES COMMON TO ALL STARS All stars start as a nebula. A nebula is a large cloud of gas and dust. Gravity can pull some of the gas

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

27.1: Characteristics of Stars

27.1: Characteristics of Stars 27.1: Characteristics of Stars STAR NOTES: Part 1 What is a Star? A body of gases that gives off energy in the form of light and heat. 27.1: Characteristics of Stars Are all stars the same? No 1. Stars

More information

Phys 100 Astronomy (Dr. Ilias Fernini) Review Questions for Chapter 9

Phys 100 Astronomy (Dr. Ilias Fernini) Review Questions for Chapter 9 Phys 0 Astronomy (Dr. Ilias Fernini) Review Questions for Chapter 9 MULTIPLE CHOICE 1. We know that giant stars are larger in diameter than the sun because * a. they are more luminous but have about the

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

Stellar Evolution Notes

Stellar Evolution Notes Name: Block: Stellar Evolution Notes Stars mature, grow old and die. The more massive a star is, the shorter its life will be. Our Sun will live about 10 billion years. It is already 5 billion years old,

More information

Stellar Astronomy Sample Questions for Exam 3

Stellar Astronomy Sample Questions for Exam 3 Stellar Astronomy Sample Questions for Exam 3 Chapter 7 1. A protostar is formed by a) the rapid expansion of gas from an exploding star. b) the gravitational collapse of a rotating interstellar cloud.

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

NSB ideas on Hertzsprung-Russell diagram

NSB ideas on Hertzsprung-Russell diagram Contents Big ideas Not so big ideas about the sun Not so big ideas about Hertzsprung-Russell diagram Not so big ideas about white dwarfs, neutron stars, and black holes Questions on chapter 10, 11, 12,

More information

IB Physics - Astronomy

IB Physics - Astronomy Solar System Our Solar System has eight planets. The picture below shows their relative sizes, but NOT their relative distances. A planet orbits the sun, and has gravitationally cleared its orbital area

More information

Astronomy 1143 Final Exam Review Answers

Astronomy 1143 Final Exam Review Answers Astronomy 1143 Final Exam Review Answers Prof. Pradhan April 24, 2015 What is Science? 1. Explain the difference between astronomy and astrology. 2. What number is the metric system based around? What

More information

Astronomy Part 1 Regents Questions

Astronomy Part 1 Regents Questions Regents Questions 1. The Sun revolves around the center of A) Polaris B) Aldebaran C) Earth D) the Milky Way Galaxy 4. In which sequence are the items listed from least total mass to greatest total mass?

More information

Astronomy 122. Lunar Eclipse. Make sure to pick up a grating from Emily! You need to give them back after class.

Astronomy 122. Lunar Eclipse. Make sure to pick up a grating from Emily! You need to give them back after class. Astronomy 122 Make sure to pick up a grating from Emily! You need to give them back after class. This Class (Lecture 11): Twinkle, Twinkle, Little Star Next Class: Stellar Evolution: The Main Sequence

More information

Star Formation A cloud of gas and dust, called a nebula, begins spinning & heating up. Eventually, it gets hot enough for fusion to take place, and a

Star Formation A cloud of gas and dust, called a nebula, begins spinning & heating up. Eventually, it gets hot enough for fusion to take place, and a Stars Star- large ball of gas held together by gravity that produces tremendous amounts of energy and shines Sun- our closest star Star Formation A cloud of gas and dust, called a nebula, begins spinning

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

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

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

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