Stellar Nucleosynthesis
|
|
- Sabrina Lee Clark
- 6 years ago
- Views:
Transcription
1 Stellar Nucleosynthesis What makes the sun shine? Gravita7onal contrac7on Chemical reac7ons Nucleosynthesis Stellar Nucleosynthesis The PP chain The CNO cycle The Triple alpha process and on to Fe Stellar Spectra Blackbody spectrum Con7nuum Emission and absorp7on lines The Harvard classifica7on sequence
2 What makes the Sun Shine Luminosity of Sun measured to be: 3.8x10 26 W (from measured flux W m - 2 and distance) Gravita7onal contrac7on (Kelvin- Helmholtz): Grav. Energy is u=m.gm/r = 4 x10 41 J (if all mass placed at surface) Sufficient to fuel sun for 33 million years Oldest rocks dated to be ~4billion years Chemical reac7ons: Burning Coal releases: J per atom Luminosity implies a mass loss of 2x10 26 kg per year Sufficient for sun to last 10 thousand years Nuclear Fusion (Einstein): E=mc 2 implies E=1.8x10 47 J Sufficient to fuel sun for 15,010 billion years
3 Stellar Nucleosynthesis Base fuel is hydrogen (and some helium with traces of CNO) Three key reac7on chains: Proton- proton chain Carbon- Nitrogen- Oxygen cycle Triple- Alpha process But fusion requires high temperatures
4 Core Temperature of Sun Assuming the Sun is in hydrosta7c equilibrium the thermal pressure is sufficient to resist gravita7onal contrac7on Crudely, consider the mass (m) pressing on the core: m =!AR F = GmM R 2 P c = F A =!GM R = G!AM R = (N /V)kT c P c = nkt c =!GM R T c = nm pgm nkr = m pgm kr T c = 23 million K Assumes constant density so not quite right but true answer based on more precise equa7ons which incorporate the density varia7on is close: 15 million K Enough to overcome the Coulomb Force to allow Fusion to occur
5 Nucleon Binding Energies
6 Valley of Stability
7 The p- p chain
8 CNO cycle Another way to progress Hydrogen to Helium Requires Carbon to be present which acts as a catalyst
9 To pp or to CNO? Efficiency depends on temperature of the core, which govern the reac7on rates. For M O. < 1.3 pp dominates. For M O. > 1.3 CNO will dominate.
10 Beyond Helium Numerous paths exist to progress up the valley of stability if other elements are already present but generally require even more temperature/pressure to occur This will only happen in very massive stars or during SN explosion (see later lecture). CNO cycle
11 Beyond Helium: Triple alpha Major bojle neck due to instability (low binding energy) of elements with atomic numbers 5-8 Progression depends on reversible reac7on. High density and abundant energy required For triple- alpha to occur = High mass stars only
12 Triple- α only occurs in massive stars
13
14 Black body spectrum Hojer star spectra peak at bluer wavelengths = BLUE Colder star spectra peak at red or near- IR wavelengths= RED Overall a hojer objects gives off more energy (integral under curve)
15 Solar spectrum v Black Body General con7nuum shape OK but lots of lines on top, why?
16 Stellar spectra Stars are hot gas balls and behave like any hot gas: Black body spectrum Intensity Energy density I(!,T ) = 2h! 3 c 2 (e h! kt!1) u(!,t ) = 4" c I(v,T ) in Wm - 2 Hz - 1 ster - 1 in Wm - 3 Hz - 1 Wien s displacement Law! MAX = 2.9!10"3 T Stephan- Boltzmann Law From integra7ng the energy density or for spherically symmetrical systems:! " 0! = " AT 4 = u(v,t )dv L = 4# R 2 "T 4
17 Surface Temp of Sun The Sun s black body spectrum peaks at 500nm use Wein s Law to get temperature? T Surface = 2.9!10"3 = 5800K "9 500!10 Surface temperature is 5800K Core temperature is 15 million K Nuclo- synthesis only occurs in the solar core Core radius ~20-25% of the Solar Radius, enclosing ~10% of the Sun s mass
18 Implied solar radius Can use Stefan- Boltzmann Law to measure implied solar radius, using known Luminosity and Temp. R = L 4!"T 4 = 3.8! ! (5.67!10 "8 ) R = 7.0!10 8 m Note have used slightly more accurate value of Temp
19 Kirchhoff s laws Spectral analysis shows us: 1) A hot opaque body, such as a hot dense gas, emits light at all wavelengths - i.e. it produces a con7nuous 'blackbody' spectrum 2) A hot transparent gas emits an emission- line spectrum - a series of bright spectral lines, plus a faint superimposed con7nuous spectrum. 3) A cool transparent gas in front of a con7nuous- spectrum source produces an absorp7on- line spectrum - a series of dark spectral lines superimposed upon the con7nuous spectrum.
20 Kirchhoff s laws of spectral analysis blackbody 3. Continuous + absorption-line spectrum Cloud of gas prism prism prism 2. Emission-line spectrum + weak continuum 1. Continuous spectrum
21 Absorp7on and Emission Lines
22 Hydrogen oren seen in both emission and absorp7on.
23 Hydrogen series UV OPTICAL NIR FIR mm/radio
24 Rydberg Formulae for Hydrogen 1 " = R % #' & 1 n 1 2 $ 1 n 2 2 ( * )
25 Each element has a characteris7c spectral pajern
26 Cold, low- mass, red Examples of stellar spectra Hot, high- mass, Blue
27 Harvard Spectral Sequence No longer used Oh, Be A Fine Girl/Guy Kiss Me (Right Now Swee7e)
28 Stellar sequence in 2D format
Stellar Nucleosynthesis
Stellar Nucleosynthesis What makes the sun shine? Gravita7onal contrac7on Chemical reac7ons Nucleosynthesis Stellar Nucleosynthesis The PP chain The CNO cycle The Triple alpha process and on to Fe Stellar
More informationEVOLUTION 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 informationLIFE CYCLE OF A STAR
LIFE CYCLE OF A STAR First stage = Protostar PROTOSTAR Cloud of gas and dust many light-years across Gravity tries to pull the materials together Eventually, at the center of the ball of dust and gas,
More informationStellar Structure. Observationally, we can determine: Can we explain all these observations?
Stellar Structure Observationally, we can determine: Flux Mass Distance Luminosity Temperature Radius Spectral Type Composition Can we explain all these observations? Stellar Structure Plan: Use our general
More informationLIFE CYCLE OF A STAR
LIFE CYCLE OF A STAR First stage = Protostar PROTOSTAR Cloud of gas and dust many light-years across Gravity tries to pull the materials together Eventually, at the center of the ball of dust and gas,
More informationTeacher 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 informationThe Life Histories of Stars I. Birth and Violent Lives
The Life Histories of Stars I Birth and Violent Lives Stellar evolution--first problem for new discipline of astrophysics What is a star? What is it made of? How does it produce and release energy? How
More informationAstronomy 1102 Exam #1 Chapters 1,2,5,6 & 16
Astronomy 1102 Exam #1 Chapters 1,2,5,6 & 16 Chapter 1 Degrees- basic unit of angle measurement, designated by the symbol -a full circle is divided into 360 and a right angle measures 90. arc minutes-one-sixtieth
More informationaka 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 informationProperties of Electromagnetic Radiation Chapter 5. What is light? What is a wave? Radiation carries information
Concepts: Properties of Electromagnetic Radiation Chapter 5 Electromagnetic waves Types of spectra Temperature Blackbody radiation Dual nature of radiation Atomic structure Interaction of light and matter
More informationProblem Set 2 Solutions
Problem Set 2 Solutions Problem 1: A A hot blackbody will emit more photons per unit time per unit surface area than a cold blackbody. It does not, however, necessarily need to have a higher luminosity,
More informationSelected Questions from Minute Papers. Outline - March 2, Stellar Properties. Stellar Properties Recap. Stellar properties recap
Black Holes: Selected Questions from Minute Papers Will all the material in the Milky Way eventually be sucked into the BH at the center? Does the star that gives up mass to a BH eventually get pulled
More informationAstonomy 62 Lecture #10. Last Time. Applications of Stefan-Boltzmann Law Color Magnitudes Color Index
Last Time Applications of Stefan-Boltzmann Law Color Magnitudes Color Index Standard Visual Band Filters U B V R I Flux through filter X: F x = 0 F S x d F x F x W x Apparent Color Magnitude: m x,1 m x,2
More informationASTR-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 informationStars and their properties: (Chapters 11 and 12)
Stars and their properties: (Chapters 11 and 12) To classify stars we determine the following properties for stars: 1. Distance : Needed to determine how much energy stars produce and radiate away by using
More informationThe 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 informationStellar energy generation on the main sequence
Stellar energy generation on the main sequence Once fusion reactions begin at the center of a cloud of gas, we call the object a star. For the bulk of its lifetime, a star fuses hydrogen into helium in
More informationLight 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 informationToday. Homework Due. Stars. Properties (Recap) Nuclear Reactions. proton-proton chain. CNO cycle. Stellar Lifetimes
Today Stars Properties (Recap) Nuclear Reactions proton-proton chain CNO cycle Stellar Lifetimes Homework Due Stellar Properties Luminosity Surface Temperature Size Mass Composition Stellar Properties
More informationParallax: 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 information11/19/08. Gravitational equilibrium: The outward push of pressure balances the inward pull of gravity. Weight of upper layers compresses lower layers
Gravitational equilibrium: The outward push of pressure balances the inward pull of gravity Weight of upper layers compresses lower layers Gravitational equilibrium: Energy provided by fusion maintains
More informationToday. 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 informationLecture #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 informationTypes 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 informationThe 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 informationLecture 14: The Sun and energy transport in stars. Astronomy 111
Lecture 14: The Sun and energy transport in stars Astronomy 111 Energy transport in stars What is a star? What is a star composed of? Why does a star shine? What is the source of a star s energy? Laws
More informationChapter 9 The Sun. Nuclear fusion: Combining of light nuclei into heavier ones Example: In the Sun is conversion of H into He
Our sole source of light and heat in the solar system A common star: a glowing ball of plasma held together by its own gravity and powered by nuclear fusion at its center. Nuclear fusion: Combining of
More informationOur sole source of light and heat in the solar system. A very common star: a glowing g ball of gas held together by its own gravity and powered
The Sun Visible Image of the Sun Our sole source of light and heat in the solar system A very common star: a glowing g ball of gas held together by its own gravity and powered by nuclear fusion at its
More informationChapter 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 informationAs the central pressure decreases due to the increase of μ, the stellar core contracts and the central temperature increases. This increases the
Stellar Evolu,on Stars spend most of their lives on the main sequence. Evidence for this is provided by the fact that 90% of stars observable from Earth are main- sequence stars. Stellar evolu,on during
More informationThe Nature of Light I: Electromagnetic Waves Spectra Kirchoff s Laws Temperature Blackbody radiation
The Nature of Light I: Electromagnetic Waves Spectra Kirchoff s Laws Temperature Blackbody radiation Electromagnetic Radiation (How we get most of our information about the cosmos) Examples of electromagnetic
More informationBook 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 informationLecture 12: Making the Sun Shine Readings: Sections 18-1, 18-4 and Box 18-1
Lecture 12: Making the Sun Shine Readings: Sections 18-1, 18-4 and Box 18-1 Key Ideas Stars shine because they are hot need an internal energy source to stay hot Kelvin-Helmholtz Mechanism Energy from
More informationTest 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 informationTuesday, 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 informationAnnouncements. There is no homework next week. Tuesday s sections (right after the midterm) will be cancelled.
1 Announcements The Midterm is one week away! Bring: Calculator, scantron (big red form), pencil No notes, cellphones, or books allowed. Homework #4 is due this thursday There is no homework next week.
More informationLIGHT. 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 information3/26/2018. 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 informationProf. Jeff Kenney Class 4 May 31, 2018
Prof. Jeff Kenney Class 4 May 31, 2018 Which stellar property can you estimate simply by looking at a star on a clear night? A. distance B. diameter C. luminosity D. surface temperature E. mass you can
More informationJames Maxwell ( )
From Atoms To Stars James Maxwell (1831 1879) Finalized the work of others on electricity and magnetism. He formulated Maxwell Equations for the electromagnetic field. His equations predicted the existence
More informationRecall: The Importance of Light
Key Concepts: Lecture 19: Light Light: wave-like behavior Light: particle-like behavior Light: Interaction with matter - Kirchoff s Laws The Wave Nature of Electro-Magnetic Radiation Visible light is just
More informationASTRONOMY 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 informationHigh Mass Stars. Dr Ken Rice. Discovering Astronomy G
High Mass Stars Dr Ken Rice High mass star formation High mass star formation is controversial! May form in the same way as low-mass stars Gravitational collapse in molecular clouds. May form via competitive
More informationChapter 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 informationAnnouncements. 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 informationAtoms 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 informationAstro 1050 Wed. Apr. 5, 2017
Astro 1050 Wed. Apr. 5, 2017 Today: Ch. 17, Star Stuff Reading in Horizons: For Mon.: Finish Ch. 17 Star Stuff Reminders: Rooftop Nighttime Observing Mon, Tues, Wed. 1 Ch.9: Interstellar Medium Since stars
More informationThe Sun. The Sun is a star: a shining ball of gas powered by nuclear fusion. Mass of Sun = 2 x g = 330,000 M Earth = 1 M Sun
The Sun The Sun is a star: a shining ball of gas powered by nuclear fusion. Mass of Sun = 2 x 10 33 g = 330,000 M Earth = 1 M Sun Radius of Sun = 7 x 10 5 km = 109 R Earth = 1 R Sun Luminosity of Sun =
More informationAstronomy 1 Winter 2011
Astronomy 1 Winter 2011 Lecture 8; January 24 2011 Previously on Astro 1 Light as a wave The Kelvin Temperature scale What is a blackbody? Wien s law: λ max (in meters) = (0.0029 K m)/t. The Stefan-Boltzmann
More informationNuclear Astrophysics. Lecture 10 Thurs. Jan. 12, 2012 Prof. Shawn Bishop, Office 2013, Ex
Nuclear Astrophysics Lecture 10 Thurs. Jan. 12, 2012 Prof. Shawn Bishop, Office 2013, Ex. 12437 shawn.bishop@ph.tum.de 1 Summary of Reaction Rate 2 Energy Generation & Standard Model Let us consider a
More informationTaking Fingerprints of Stars, Galaxies, and Other Stuff. The Bohr Atom. The Bohr Atom Model of Hydrogen atom. Bohr Atom. Bohr Atom
Periodic Table of Elements Taking Fingerprints of Stars, Galaxies, and Other Stuff Absorption and Emission from Atoms, Ions, and Molecules Universe is mostly (97%) Hydrogen and Helium (H and He) The ONLY
More informationHow does the Sun shine? What is the Sun s structure? Lifetime of the Sun. Luminosity of the Sun. Radiation Zone. Core 3/30/17
What is the Sun s structure? From inside out, the layers are: Core Radiation Zone Convection Zone Photosphere Chromosphere Corona How does the Sun shine? The Sun has its own energy source Main difference
More informationThe 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 informationSolar Interior. Sources of energy for Sun Nuclear fusion Solar neutrino problem Helioseismology
Solar Interior Sources of energy for Sun Nuclear fusion Solar neutrino problem Helioseismology Solar Atmosphere Solar interior Solar facts Luminosity: 3.8x10 26 J/s Mass: 2.0x10 30 kg Composition: 73%
More information10/31/2018. 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 informationFilling the intellectual Vacuum: Energy Production. Contenders: From early 1920s: probably fusion, but how?
Life of Stars Filling the intellectual Vacuum: Contenders: Energy Production Gravitational contraction Radioactivity (1903) Annihilation (E=mc 2, 1905) of proton and electron Hydrogen to helium nuclear
More informationChapter 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 informationUNIVERSITY OF SOUTHAMPTON
UNIVERSITY OF SOUTHAMPTON PHYS3010W1 SEMESTER 2 EXAMINATION 2014-2015 STELLAR EVOLUTION: MODEL ANSWERS Duration: 120 MINS (2 hours) This paper contains 8 questions. Answer all questions in Section A and
More informationThe Sun Our Star. Properties Interior Atmosphere Photosphere Chromosphere Corona Magnetism Sunspots Solar Cycles Active Sun
The Sun Our Star Properties Interior Atmosphere Photosphere Chromosphere Corona Magnetism Sunspots Solar Cycles Active Sun General Properties Not a large star, but larger than most Spectral type G2 It
More informationAstronomy 1 Fall Reminder: When/where does your observing session meet? [See from your TA.]
Astronomy 1 Fall 2016 Reminder: When/where does your observing session meet? [See email from your TA.] Lecture 9, October 25, 2016 Previously on Astro-1 What is the Moon made of? How did the Moon form?
More informationStars. The composition of the star It s temperature It s lifespan
Stars Stars A star is a ball of different elements in the form of gases The elements and gases give off electromagnetic radiation (from nuclear fusion) in the form of light Scientists study the light coming
More informationStellar Evolution: Outline
Stellar Evolution: Outline Interstellar Medium (dust) Hydrogen and Helium Small amounts of Carbon Dioxide (makes it easier to detect) Massive amounts of material between 100,000 and 10,000,000 solar masses
More informationChapter 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 informationAstro Instructors: Jim Cordes & Shami Chatterjee.
Astro 2299 The Search for Life in the Universe Lecture 8 Last time: Formation and function of stars This time (and probably next): The Sun, hydrogen fusion Virial theorem and internal temperatures of stars
More informationReview from last class:
Review from last class: Properties of photons Flux and luminosity, apparent magnitude and absolute magnitude, colors Spectroscopic observations. Doppler s effect and applications Distance measurements
More informationAy 1 Lecture 8. Stellar Structure and the Sun
Ay 1 Lecture 8 Stellar Structure and the Sun 8.1 Stellar Structure Basics How Stars Work Hydrostatic Equilibrium: gas and radiation pressure balance the gravity Thermal Equilibrium: Energy generated =
More informationSources of radiation
Sources of radiation Most important type of radiation is blackbody radiation. This is radiation that is in thermal equilibrium with matter at some temperature T. Lab source of blackbody radiation: hot
More informationStars: 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 informationIn class quiz - nature of light. Moonbow with Sailboats (Matt BenDaniel)
In class quiz - nature of light Moonbow with Sailboats (Matt BenDaniel) Nature of light - review Light travels at very high but finite speed. Light is electromagnetic wave characterized by wavelength (or
More informationChapters 12 and 13 Review: The Life Cycle and Death of Stars. How are stars born, and how do they die? 4/1/2009 Habbal Astro Lecture 27 1
Chapters 12 and 13 Review: The Life Cycle and Death of Stars How are stars born, and how do they die? 4/1/2009 Habbal Astro 110-01 Lecture 27 1 Stars are born in molecular clouds Clouds are very cold:
More informationStars: Birth, Life and Death
Stars: Birth, Life and Death Stars are formed from interstellar material which is compressed by gravity They spend >90% of their lives burning Hydrogen into Helium how they die depends on mass large stars
More informationAnnouncements. - Homework #5 due today - Review on Monday 3:30 4:15pm in RH103 - Test #2 next Tuesday, Oct 11
Announcements - Homework #5 due today - Review on Monday 3:30 4:15pm in RH103 - Test #2 next Tuesday, Oct 11 Review for Test #2 Oct 11 Topics: The Solar System and its Formation The Earth and our Moon
More informationStellar Interior: Physical Processes
Physics Focus on Astrophysics Focus on Astrophysics Stellar Interior: Physical Processes D. Fluri, 29.01.2014 Content 1. Mechanical equilibrium: pressure gravity 2. Fusion: Main sequence stars: hydrogen
More informationExam #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 informationChapter 12: The Life Cycle of Stars (contʼd) How are stars born, and how do they die? 4/9/09 Habbal Astro Lecture 25 1
Chapter 12: The Life Cycle of Stars (contʼd) How are stars born, and how do they die? 4/9/09 Habbal Astro 110-01 Lecture 25 1 12.3 Life as a High-Mass Star Learning Goals What are the life stages of a
More informationPre Main-Sequence Evolution
Stellar Astrophysics: Stellar Evolution Pre Main-Sequence Evolution The free-fall time scale is describing the collapse of the (spherical) cloud to a protostar 1/2 3 π t ff = 32 G ρ With the formation
More informationTaking fingerprints of stars, galaxies, and interstellar gas clouds
- - Taking fingerprints of stars, galaxies, and interstellar gas clouds Absorption and emission from atoms, ions, and molecules Periodic Table of Elements The universe is mostly hydrogen H and helium He
More informationHydrogen 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 informationObserving Habitable Environments Light & Radiation
Homework 1 Due Thurs 1/14 Observing Habitable Environments Light & Radiation Given what we know about the origin of life on Earth, how would you recognize life on another world? Would this require a physical
More informationParallax: 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 informationAnnouncements. - Marie Friday 3/17, 4-5pm NatSci2 Annex Plato Sunday, 3/20, 3-4pm, NatSci2 Annex 101
Announcements Please fill out an on-line course evaluation Final Exam: Wednesday, 3/22, 7:30pm - 3 hours - same format, rules as midterm: multiple choice with formula sheet, closed book and notes, bring
More informationBirth & Death of Stars
Birth & Death of Stars Objectives How are stars formed How do they die How do we measure this The Interstellar Medium (ISM) Vast clouds of gas & dust lie between stars Diffuse hydrogen clouds: dozens of
More informationLast time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy.
Last time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy. Last time: looked at proton-proton chain to convert Hydrogen into Helium, releases energy. Fusion rate ~ Temperature
More informationThe 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 informationInstructor: Juhan Frank. Identify the correct answers by placing a check between the brackets ë ë. Check ALL
Name:... ASTRONOMY 1102 í 1 Instructor: Juhan Frank Second Test ífall 1999í Friday October 15 Part I í Multiple Choice questions è3 ptsèquestion; total = 60 ptsè Identify the correct answers by placing
More informationAST101 Lecture 13. The Lives of the Stars
AST101 Lecture 13 The Lives of the Stars A Tale of Two Forces: Pressure vs Gravity I. The Formation of Stars Stars form in molecular clouds (part of the interstellar medium) Molecular clouds Cold: temperatures
More informationAstronomy 1144 Exam 3 Review
Stars and Stellar Classification Astronomy 1144 Exam 3 Review Prof. Pradhan 1. What is a star s energy source, or how do stars shine? Stars shine by fusing light elements into heavier ones. During fusion,
More informationStellar Evolution Stars spend most of their lives on the main sequence. Evidence: 90% of observable stars are main-sequence stars.
Stellar Evolution Stars spend most of their lives on the main sequence. Evidence: 90% of observable stars are main-sequence stars. Stellar evolution during the main-sequence life-time, and during the post-main-sequence
More informationThe Later Evolution of Low Mass Stars (< 8 solar masses)
The Later Evolution of Low Mass Stars (< 8 solar masses) http://apod.nasa.gov/apod/astropix.html The sun - past and future central density also rises though average density decreases During 10 billion
More informationTaking fingerprints of stars, galaxies, and interstellar gas clouds. Absorption and emission from atoms, ions, and molecules
Taking fingerprints of stars, galaxies, and interstellar gas clouds Absorption and emission from atoms, ions, and molecules 1 Periodic Table of Elements The universe is mostly hydrogen H and helium He
More informationA 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 informationMar 22, INSTRUCTIONS: First ll in your name and social security number (both by printing
ASTRONOMY 0089: EXAM 2 Class Meets M,W,F, 1:00 PM Mar 22, 1996 INSTRUCTIONS: First ll in your name and social security number (both by printing and by darkening the correct circles). Sign your answer sheet
More informationReview 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 informationAstronomy 1 Fall 2016
Astronomy 1 Fall 2016 Lecture11; November 1, 2016 Previously on Astro-1 Introduction to stars Measuring distances Inverse square law: luminosity vs brightness Colors and spectral types, the H-R diagram
More informationLecture 13: The Sun, and how stars work. Astronomy 111 Wednesday October 11, 2017
Lecture 13: The Sun, and how stars work Astronomy 111 Wednesday October 11, 2017 Reminders Star party tomorrow night! Homework #6 due Monday How do stars work? What is a star? What is a star composed of?
More information! p. 1. Observations. 1.1 Parameters
1 Observations 11 Parameters - Distance d : measured by triangulation (parallax method), or the amount that the star has dimmed (if it s the same type of star as the Sun ) - Brightness or flux f : energy
More informationFamily 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 informationToday. Stars. Properties (Recap) Binaries. Stellar Lifetimes
Today Stars Properties (Recap) Binaries Stellar Lifetimes 1 Exam Review Session This Tuesday, 6-8 PM, PHYS 1410 (the large lecture hall next to ours) Completely driven by your questions! The TAs will not
More informationChapter 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 informationIntroduction to the Sun
Lecture 15 Introduction to the Sun Jiong Qiu, MSU Physics Department Open Q: what physics do we learn about the Sun? 1. Energy - nuclear energy - magnetic energy 2. Radiation - continuum and line emissions;
More information