Fundamental (Sub)stellar Parameters: Masses and Radii. PHY 688, Lecture 10
|
|
- Hope Spencer
- 5 years ago
- Views:
Transcription
1 Fundamental (Sub)stellar Parameters: Masses and Radii PHY 688, Lecture 10
2 Outline Review of previous lecture brown dwarf effective temperatures finding cool brown dwarfs current problem: what are the coolest brown dwarfs? (Sub)stellar masses and radii binary stars Current astrophysics problem: dynamical mass and radius determination of brown dwarf binaries Feb 16, 2009 PHY 688, Lecture 10 2
3 Previously in PHY 688 Feb 16, 2009 PHY 688, Lecture 10 3
4 (Sub)stellar Effective Temperature % T eff = d 2 ' 2 & R * # f " d" ( $ * ) 1 4 f λ recorded spectrum d trigonometric parallax distance R * (sub)stellar radius (for brown dwarfs R * 0.1 R Sun ) (Cushing Feb 16, 2009 et al. 2006; Marley & Leggett 2008) PHY 688, Lecture 10 4
5 Teff s of L and T Dwarfs Feb 16, 2009 PHY 688, Lecture 10 (Kirkpatrick 2005) 5
6 T eff s without Spectra estimate SpT from color(s): e.g., z J use SpT-specific bolometric correction (BC) to get total flux z J get T eff if distance d is known (Cushing Feb 16, 2009 et al. 2006; Marley & Leggett 2008) PHY 688, Lecture 10 6
7 Bolometric Corrections BC λ (SpT) = M bol (SpT) M λ M bol (SpT) is known from the few objects of given SpT with nearcomplete SEDs BC(Sun) 0 mag at all wavelengths λ Feb 16, 2009 PHY 688, Lecture 10 (Golimowski et al. 2004) 7
8 Searching for Cool Brown Dwarfs: T s and Y s Y? L T0 T4 T5 T8 Y? SDSS (Fan et al. 2001) Feb 16, 2009 PHY 688, Lecture 10 8
9 Possible NH 3 at T8.5 T9 The First Y0 s? K S (2.15 µm) (T8) (T8) CFBDS 0059 (T8.5) New T9 dwarf from CFBDS T eff 600 K: coolest brown dwarf to date (T9) Feb 16, 2009 (Delorme PHY 688, et al. Lecture 2008) 10 9
10 UKDISS Large-Area Sky Surveys of the Near Future UKIRT µm, 18% sky K = 18.4 mag cf. K = 14.3 for 2MASS UKIRT (3 m, ground-based) WISE 3 25 µm, 99% sky 0.4 m, space-based November 2009 launch 8-month lifetime LSST PanSTARRS / LSST visible, ~75% sky, synoptic 4 x 1.8 m / 8.4 m ground-based 2009? / 2015 Feb 16, 2009 PHY 688, Lecture 10 10
11 Outline Review of previous lecture brown dwarf effective temperatures finding cool brown dwarfs current problem: what are the coolest brown dwarfs? (Sub)stellar masses and radii binary stars Current astrophysics problem: dynamical mass and radius determination of brown dwarf binaries Feb 16, 2009 PHY 688, Lecture 10 11
12 Mass most fundamental of stellar parameters L M 3.8 τ MS yr (M/M Sun ) 2.8 impossible to measure for isolated stars Feb 16, 2009 PHY 688, Lecture 10 12
13 Dynamical Masses: Binary Stars to the Rescue ~ 1/3 of stars are binaries ~ 50% of Sun-like (~ 1 M Sun ) stars are binaries Feb 16, 2009 PHY 688, Lecture 10 13
14 Dynamical Masses: Binary Stars to the Rescue Resolved visual binaries: see stars separately, measure orbital axes and speeds directly. Astrometric binaries: only brighter member seen, with periodic wobble in the track of its proper motion. Spectroscopic binaries: unresolved (relatively close) binaries told apart by periodically oscillating Doppler shifts in spectral lines. Periods = days to years. Eclipsing binaries: orbits seen nearly edge on, so that the stars actually eclipse one another. (Most useful.) Feb 16, 2009 PHY 688, Lecture 10 14
15 Visual Binary GJ 569Bab binary brown dwarf a > 5 10AU (Lane et al. 2001) Feb 16, 2009 PHY 688, Lecture 10 15
16 First Dynamical Mass of T Dwarf (Visual) Binary: 2MASS J AB (Liu et al., 2008) Feb 16, 2009 PHY 688, Lecture 10 16
17 Astrometric Binary Feb 16, 2009 PHY 688, Lecture 10 17
18 Astrometric Binary: Sirius AB Sirius A: nearby luminous B star brightest star in the sky ~1 M Sun white dwarf companion first inferred from its large astrometric effect on primary now also a visual binary B Hubble Space Telescope image Feb 16, 2009 PHY 688, Lecture 10 18
19 Astrometric Binary: GJ 802AB unseen brown dwarf companion a > 0.5 2AU (Pravdo et al. 2005) Feb 16, 2009 PHY 688, Lecture 10 19
20 Spectroscopic Binary double-lined (SB2) spectra of both stars visible (a) (b) (d) (a) (b) (c) (c) (d) single-lined (SB1) only spectrum of brighter star visible Feb 16, 2009 PHY 688, Lecture (d)
21 Radial Velocity vs. Time for Doublelined SB in a Circular Orbit Feb 16, 2009 PHY 688, Lecture 10 21
22 Radial Velocity vs. Time for Doublelined SB in Elliptical Orbit (e = 0.4) Feb 16, 2009 PHY 688, Lecture 10 22
23 Spectroscopic Binary: 51 Peg Ab first planet detected around a mainsequence star primary SpT: G2 V M p sin i = 0.47 M Jup (SB1) (Mayor & Queloz 1995) Feb 16, 2009 PHY 688, Lecture 10 23
24 Visual + Spectroscopic Binary Brown Dwarf: Gl 569Bab first BD dynamical mass M tot = 0.l25 ± M Sun (Lane et al. 2001; Simon et al. 2006) Feb 16, 2009 PHY 688, Lecture 10 24
25 Totally Eclipsing Binaries Feb 16, 2009 PHY 688, Lecture 10 25
26 Totally Eclipsing Binaries t a start of secondary ingress t b end of secondary ingress t c start of secondary egress t d end of secondary egress Feb 16, 2009 PHY 688, Lecture 10 26
27 Dynamical Mass Determination If orbital major axes (relative to center of mass) or radial velocity amplitudes are known, so is the ratio of masses: m m 1 2 a2 = = a 1 v v 2r 1r If the period, P, and the sum of major axis lengths, a = a 1 + a 2, are known, Kepler s third law can give masses separately: 4" # & P = % $ G(m 1 + m 2 ) a3 ( ' Feb 16, 2009 PHY 688, Lecture 10 27
28 Dynamical Mass Determination If only the two radial velocities are known (SB2), the sum of masses (from Kepler s third law) is: m + m = 1 2 P 2' G If only one radial velocity is known (SB1), a useful quantity is the mass function: f (m 1,m 2 ) = v 3 1 P 2"G = ( m 2 sin i) 3 ( m 1 + m 2 ) 2 If orientation angle of orbit, i, is known, this allows separate determination of the mass(es)! # " v r + v sin i 1 2r $ & % 3 Feb 16, 2009 PHY 688, Lecture 10 28
29 Other Uses for Totally Eclipsing Binary Systems: Radii and T eff s Duration of eclipses and shape of light curve can be used to determine radii of stars: (radius of secondary) (radius of primary) v1 + v2 Rs = 2 t! t v1 + v2 Rl = 2 t! t ( ) 2 1 ( ) 3 1 Relative depth of primary (deepest) and secondary brightness minima of eclipses can be used to determine the ratio of effective temperatures of the stars: F0! Fprimary " Te, s # = F0! F $ secondary T % & e, l ' t 1 start of secondary ingress t 2 end of secondary ingress t 3 start of secondary egress Feb 16, 2009 PHY 688, Lecture
30 Luminosity-Mass Relation for Stars with Well-determined Orbits (Popper 1980) Feb 16, 2009 PHY 688, Lecture 10 30
31 Radius-Mass Relation for Binary Stars with Well-Determined Orbits Radius (R e ) 1 Detached binaries Semidetached/contact binaries Mass ( M e ) (Malkov 1993) Feb 16, 2009 PHY 688, Lecture 10 31
32 Temperature-Mass Relation for Stars with Well-determined Orbits Detached binaries Semidetached/contact binaries Temperature (K) Mass ( M e ) (Malkov 1993) Feb 16, 2009 PHY 688, Lecture 10 32
33 Binary Separations (Reid & Metchev 2007) Feb 16, 2009 PHY 688, Lecture 10 33
34 Binary Mass Ratio Distribution (Reid & Metchev 2007) Feb 16, 2009 PHY 688, Lecture 10 34
35 Outline Review of previous lecture brown dwarf effective temperatures finding cool brown dwarfs current problem: what are the coolest brown dwarfs? (Sub)stellar masses and radii binary stars Current astrophysics problem: dynamical mass and radius determination of brown dwarf binaries Feb 16, 2009 PHY 688, Lecture 10 35
36 First Determination of Substellar Radii (Stassun et al., 2005) Feb 16, 2009 PHY 688, Lecture 10 36
37 First Determination of Substellar Radii (Stassun et al., 2005) Feb 16, 2009 PHY 688, Lecture 10 37
38 First Determination of Substellar Radii (Stassun et al., 2005) Feb 16, 2009 PHY 688, Lecture 10 38
Fundamental (Sub)stellar Parameters: Surface Gravity. PHY 688, Lecture 11
Fundamental (Sub)stellar Parameters: Surface Gravity PHY 688, Lecture 11 Outline Review of previous lecture binary stars and brown dwarfs (sub)stellar dynamical masses and radii Surface gravity stars,
More informationToday in Astronomy 328: binary stars
Today in Astronomy 38: binary stars Binary-star systems. Direct measurements of stellar mass and radius in eclipsing binary-star systems. At right: two young binary star systems in the Taurus star-forming
More informationObserved Properties of Stars - 2 ASTR 2120 Sarazin
Observed Properties of Stars - 2 ASTR 2120 Sarazin Properties Location Distance Speed Radial velocity Proper motion Luminosity, Flux Magnitudes Magnitudes Hipparchus 1) Classified stars by brightness,
More informationObserved Properties of Stars - 2 ASTR 2110 Sarazin
Observed Properties of Stars - 2 ASTR 2110 Sarazin Properties Location Distance Speed Radial velocity Proper motion Luminosity, Flux Magnitudes Magnitudes Stellar Colors Stellar Colors Stellar Colors Stars
More informationAstronomy 421. Lecture 8: Binary stars
Astronomy 421 Lecture 8: Binary stars 1 Key concepts: Binary types How to use binaries to determine stellar parameters The mass-luminosity relation 2 Binary stars So far, we ve looked at the basic physics
More informationSearching for Other Worlds
Searching for Other Worlds Lecture 32 1 In-Class Question What is the Greenhouse effect? a) Optical light from the Sun is reflected into space while infrared light passes through the atmosphere and heats
More informationChapter 8: The Family of Stars
Chapter 8: The Family of Stars Motivation We already know how to determine a star s surface temperature chemical composition surface density In this chapter, we will learn how we can determine its distance
More informationLecture 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 information5. 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 informationElectromagnetic Spectra. AST443, Lecture 13 Stanimir Metchev
Electromagnetic Spectra AST443, Lecture 13 Stanimir Metchev Administrative Homework 2: problem 5.4 extension: until Mon, Nov 2 Reading: Bradt, chapter 11 Howell, chapter 6 Tenagra data: see bottom of Assignments
More informationMASSACHUSETTS INSTITUTE OF TECHNOLOGY Physics Department Earth, Atmospheric, and Planetary Sciences Department. Problem Set 6
MASSACHUSETTS INSTITUTE OF TECHNOLOGY Physics Department Earth, Atmospheric, and Planetary Sciences Department Astronomy 8.282J 12.402J March 17, 2006 Problem Set 6 Due: Friday, March 24 (in lecture) Reading:
More informationCharacterizing 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 informationFrom measuring and classifying the stars to understanding their physics
From measuring and classifying the stars to understanding their physics What we can measure directly: Surface temperature and color Spectrum Apparent magnitude or intensity Diameter of a few nearby stars
More informationAstr 5465 Feb. 6, 2018 Today s Topics
Astr 5465 Feb. 6, 2018 Today s Topics Stars: Binary Stars Determination of Stellar Properties via Binary Stars Classification of Binary Stars Visual Binaries Both stars visible Only one star visible Spectroscopic
More informationAstronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D.
Astronomy 113 Dr. Joseph E. Pesce, Ph.D. The Nature of Stars 8-2 Parallax For nearby stars - measure distances with parallax July 1 AU d p A A A January ³ d = 1/p (arcsec) [pc] ³ 1pc when p=1arcsec; 1pc=206,265AU=3
More informationASTR-1020: Astronomy II Course Lecture Notes Section III
ASTR-1020: Astronomy II Course Lecture Notes Section III Dr. Donald G. Luttermoser East Tennessee State University Edition 4.0 Abstract These class notes are designed for use of the instructor and students
More informationExtrasolar Planets. Methods of detection Characterization Theoretical ideas Future prospects
Extrasolar Planets Methods of detection Characterization Theoretical ideas Future prospects Methods of detection Methods of detection Methods of detection Pulsar timing Planetary motion around pulsar
More informationThe Hertzprung-Russell Diagram. The Hertzprung-Russell Diagram. Question
Key Concepts: Lecture 21: Measuring the properties of stars (cont.) The Hertzsprung-Russell (HR) Diagram (L versus T) The Hertzprung-Russell Diagram The Stefan-Boltzmann Law: flux emitted by a black body
More informationStars: basic observations
Stars: basic observations Basic properties of stars we would like to know in order to compare theory against observations: Stellar mass M Stellar radius R Surface temperature - effective temperature T
More informationThe 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 informationCharacterizing 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 informationClassical Methods for Determining Stellar Masses, Temperatures, and Radii
Classical Methods for Determining Stellar Masses, Temperatures, and Radii Willie Torres Harvard-Smithsonian Center for Astrophysics 2010 Sagan Exoplanet Summer Workshop 1 Outline Basic properties of stars
More informationUniverse. Tenth Edition. The Nature of the Stars. Parallax. CHAPTER 17 The Nature of Stars
Universe Tenth Edition The Nature of the Stars Roger A. Freedman, Robert M. Geller, William J. Kaufmann III CHAPTER 17 The Nature of Stars W. H. Freeman and Company Parallax Careful measurements of the
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 informationChapter 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 informationRelativity and Astrophysics Lecture 15 Terry Herter. RR Lyrae Variables Cepheids Variables Period-Luminosity Relation. A Stellar Properties 2
Stellar Properties Relativity and Astrophysics Lecture 15 Terry Herter Outline Spectroscopic Parallax Masses of Stars Periodic Variable Stars RR Lyrae Variables Cepheids Variables Period-Luminosity Relation
More informationLecture 16 The Measuring the Stars 3/26/2018
Lecture 16 The Measuring the Stars 3/26/2018 Test 2 Results D C B A Questions that I thought were unfair: 13, 18, 25, 76, 77, 80 Curved from 85 to 79 Measuring stars How far away are they? How bright are
More informationObserved Properties of Stars ASTR 2120 Sarazin
Observed Properties of Stars ASTR 2120 Sarazin Extrinsic Properties Location Motion kinematics Extrinsic Properties Location Use spherical coordinate system centered on Solar System Two angles (θ,φ) Right
More informationAssignments 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 informationLight and Stars ASTR 2110 Sarazin
Light and Stars ASTR 2110 Sarazin Doppler Effect Frequency and wavelength of light changes if source or observer move Doppler Effect v r dr radial velocity dt > 0 moving apart < 0 moving toward Doppler
More information15.1 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 informationHOMEWORK - Chapter 17 The Stars
Astronomy 20 HOMEWORK - Chapter 7 The Stars Use a calculator whenever necessary. For full credit, always show your work and explain how you got your answer in full, complete sentences on a separate sheet
More informationLines 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 informationBlack Hole and Host Galaxy Mass Estimates
Black Holes Black Hole and Host Galaxy Mass Estimates 1. Constraining the mass of a BH in a spectroscopic binary. 2. Constraining the mass of a supermassive BH from reverberation mapping and emission line
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 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 informationReview 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 informationMasses are much harder than distance, luminosity, or temperature. Binary Stars to the Rescue!! AST 101 Introduction to Astronomy: Stars & Galaxies
Last Two Classes Measuring the Stars AST 101 Introduction to Astronomy: Stars & Galaxies 1. Measuring distances 2. Measuring stellar luminosities 3. Measuring temperatures Next 4. Measuring masses Masses
More informationSearching for Binary Y dwarfs with the Gemini GeMS Multi-Conjugate Adaptive Optics System
Searching for Binary Y dwarfs with the Gemini GeMS Multi-Conjugate Adaptive Optics System Daniela Opitz 1,2, Chris Tinney 1,2 1 Exoplanetary Science Group, School of Physics, University of New South Wales,
More informationLecture 12: Distances to stars. Astronomy 111
Lecture 12: Distances to stars Astronomy 111 Why are distances important? Distances are necessary for estimating: Total energy released by an object (Luminosity) Masses of objects from orbital motions
More 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 informationHD Transits HST/STIS First Transiting Exo-Planet. Exoplanet Discovery Methods. Paper Due Tue, Feb 23. (4) Transits. Transits.
Paper Due Tue, Feb 23 Exoplanet Discovery Methods (1) Direct imaging (2) Astrometry position (3) Radial velocity velocity Seager & Mallen-Ornelas 2003 ApJ 585, 1038. "A Unique Solution of Planet and Star
More informationStars: Masses. V. van Gogh: Starry Night over the Rhône (1888) The WebMuseum ( original: Paris, Musée d Orsay) M E L M
Stars: asses 12 1. van Gogh: Starry ight over the hône (1888) The Webuseum (http://www.ibiblio.org/wm/; original: Paris, usée d Orsay) D D D G S 14.5" D D 12 12 D G S asses izar and B are rather typical
More informationLecture 26 The Hertzsprung- Russell Diagram January 13b, 2014
1 Lecture 26 The Hertzsprung- Russell Diagram January 13b, 2014 2 Hertzsprung-Russell Diagram Hertzsprung and Russell found a correlation between luminosity and spectral type (temperature) 10000 Hot, bright
More information301 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 informationThe Cosmic Distance Ladder
The Cosmic Distance Ladder (Mário Santos) What is it? A way to calculate distances to objects very far away based on the measured distances to nearby objects: 1. Start with the distance to the Sun (1 AU)
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 informationChapter 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 informationAstr 2320 Tues. March 7, 2017 Today s Topics
Astr 2320 Tues. March 7, 2017 Today s Topics Chapter 13: Stars: Binary Stars Determination of Stellar Properties vi Binary Stars Classification of Binary Stars Visual Binaries Both stars visible Only one
More informationExoplanet Search Techniques: Overview. PHY 688, Lecture 28 April 3, 2009
Exoplanet Search Techniques: Overview PHY 688, Lecture 28 April 3, 2009 Course administration final presentations Outline see me for paper recommendations 2 3 weeks before talk see me with draft of presentation
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 informationLecture 21. Stellar Size
Lecture 21 Stellar Mass; The Main Sequence Visual and Spectroscopic Binaries Mass and the Main Sequence Explaining the Main Sequence Mar 8, 2006 Astro 100 Lecture 21 1 Stellar Size Taking ratios to the
More informationBasic Properties of the Stars
Basic Properties of the Stars The Sun-centered model of the solar system laid out by Copernicus in De Revolutionibus (1543) made a very specific prediction: that the nearby stars should exhibit parallax
More informationMeasuring 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 informationASTR 200 : Lecture 13 Doppler Effect and binary motion
ASTR 200 : Lecture 13 Doppler Effect and binary motion 1 Announcements Reminder: Midterm is Oct 22, in class, 50 minutes long. More information provided next week. HW 1 solutions now posted on the course
More informationAstronomical Study: A Multi-Perspective Approach
Astronomical Study: A Multi-Perspective Approach Overview of Stars Motion Distances Physical Properties Spectral Properties Magnitudes Luminosity class Spectral trends Binary stars and getting masses Stellar
More informationMeasuring 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 informationInterferometry & Asteroseismology of Solar-like Stars
Interferometry & Asteroseismology of Solar-like Stars (+ their Connection to Exoplanets) Daniel Huber NASA Ames Research Center Feb 11 2014 Supergiants Giants Hot Dwarfs White Dwarfs Cool Dwarfs Griffith
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Homework Ch 7, 8, 9 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Our most detailed knowledge of Uranus and Neptune comes from 1) A) the
More informationChapter 11 Surveying the Stars
Chapter 11 Surveying the Stars Luminosity Luminosity: Rate of energy emitted by star every second. Apparent brightness (flux): Amount of energy passing through every second per unit area. Luninosity =
More informationBrown Dwarfs in the Era of WISE. Michael Cushing University of Toledo
Brown Dwarfs in the Era of WISE Michael Cushing University of Toledo WISE at 5 2015-Feb-10 Brown dwarfs were baked into WISE From the 1998 proposal for the Next Generation Sky Survey (NGSS): The primary
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 informationAstrometric monitoring of binary Brown Dwarfs with NGS and LGS Adaptive Optics
Astrometric monitoring of binary Brown Dwarfs with NGS and LGS Adaptive Optics Micaela Stumpf Astronomy with LGS AO 28.10. - 02.11.2007 Ringberg Thomas Henning Wolfgang Brandner MPIA Heidelberg Motivation
More informationStructure & Evolution of Stars 1
Structure and Evolution of Stars Lecture 2: Observational Properties Distance measurement Space velocities Apparent magnitudes and colours Absolute magnitudes and luminosities Blackbodies and temperatures
More informationASTR 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 informationMeasuring 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 informationASTR 1120 General Astronomy: Stars & Galaxies
ASTR 1120 General Astronomy: Stars & Galaxies HOMEWORK #3 due NEXT TUE, 09/29, by 5pm Fiske planetarium: The Birth of Stars by Prof. John Bally - TH 09/24-FRI 09/25, 7:30pm Astronomer s s Toolbox: What
More informationII Planet Finding.
II Planet Finding http://sgoodwin.staff.shef.ac.uk/phy229.html 1.0 Introduction There are a lot of slides in this lecture. Much of this should be familiar from PHY104 (Introduction to Astrophysics) and
More informationGaia Launched in Dec D map of the stars near Sun = 10% of Galaxy Measure the positions of a billion stars to brightness V=20 Precise to
Gaia Launched in Dec 2013 3D map of the stars near Sun = 10% of Galaxy Measure the positions of a billion stars to brightness V=20 Precise to 0.000024 arcseconds = hair at 1000km Accurate parallax/distances?
More informationAnswer Key Testname: MT S
Answer Key Testname: MT1-333-12S 1) B 2) A 3) E 4) C 5) C 6) C 7) C 8) A 9) E 10) C 11) A 12) C 13) C 14) C 15) C 16) D 17) A 18) D 19) A 20) C 21) B 22) A 23) A 24) C 25) B 26) C 27) A star with apparent
More informationOPTION E, ASTROPHYSICS TEST REVIEW
IB PHYSICS Name: DEVIL PHYSICS Period: Date: BADDEST CLASS ON CAMPUS OPTION E, ASTROPHYSICS TEST REVIEW S1. This question is about the nature of certain stars on the Hertzsprung-Russell diagram and determining
More information1 of 6 5/2/2015 6:12 PM
1 of 6 5/2/2015 6:12 PM 1. What is parallax? The distance to an object, measured in parsecs. The difference between the apparent and absolute magnitude. The apparent shift in POSITION of an object caused
More informationIII The properties of extrasolar planets
III The properties of extrasolar planets (as of early 2016) http://sgoodwin.staff.shef.ac.uk/phy229.html 3.0 Introduction This lecture will discuss what we have found so far. It is important to remember
More information7. BINARY STARS (ZG: 12; CO: 7, 17)
7. BINARY STARS (ZG: 12; CO: 7, 17) most stars are members of binary systems or multiple systems (triples, quadruples, quintuplets,...) orbital period distribution: P orb = 11 min to 10 6 yr the majority
More informationProperties of Stars. For such huge objects, stars have comparatively simple properties when seen from a long way off
Properties of Stars For such huge objects, stars have comparatively simple properties when seen from a long way off apparent magnitude distance and direction in space luminosity - absolute magnitude temperature
More informationDetermining 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 informationECLIPSING AND SPECTROSCOPIC BINARY STARS
FINAL YEAR SEMINAR, OLD PROGRAM ECLIPSING AND SPECTROSCOPIC BINARY STARS Author: Franci Gorjup Mentor: Prof. dr. Tomaž Zwitter Ljubljana, December 2013 Abstract: First, we will see, what kind of binary
More informationGuiding Questions. Measuring Stars
Measuring Stars Guiding Questions 1. How far away are the stars? 2. What is meant by a first-magnitude or second magnitude star? 3. Why are some stars red and others blue? 4. What are the stars made of?
More informationThe cosmic distance scale
The cosmic distance scale Distance information is often crucial to understand the physics of astrophysical objects. This requires knowing the basic properties of such an object, like its size, its environment,
More informationExtrasolar Transiting Planets: Detection and False Positive Rejection
4 Harvard-Smithsonian Center for Astrophysics Extrasolar Transiting Planets: Detection and False Positive Rejection Willie Torres Harvard-Smithsonian Center for Astrophysics Young Planetary Systems Workshop
More informationExoplanetary Atmospheres: Temperature Structure of Irradiated Planets. PHY 688, Lecture 23 Mar 20, 2009
Exoplanetary Atmospheres: Temperature Structure of Irradiated Planets PHY 688, Lecture 23 Mar 20, 2009 Outline Review of previous lecture hot Jupiters; transiting planets primary eclipses and atmospheric
More informationPlanet Detection! Estimating f p!
Planet Detection! Estimating f p! Can We See Them?! Not easily! Best cases were reported in late 2008! Will see these later! Problem is separating planet light from star light! Star is 10 9 times brighter
More informationScience Olympiad Astronomy C Division Event National Exam
Science Olympiad Astronomy C Division Event National Exam University of Nebraska-Lincoln May 15-16, 2015 Team Number: Team Name: Instructions: 1) Please turn in all materials at the end of the event. 2)
More informationTechniques for measuring astronomical distances generally come in two variates, absolute and relative.
Chapter 6 Distances 6.1 Preliminaries Techniques for measuring astronomical distances generally come in two variates, absolute and relative. Absolute distance measurements involve objects possibly unique
More informationA Survey of Stellar Families Multiplicity of Solar-type Stars
A Survey of Stellar Families Multiplicity of Solar-type Stars Advisor: Dr. Hal McAlister GSU Committee members: Dr. Doug Gies GSU Deepak Raghavan Ph.D. Dissertation Talk March 17, 2009 Dr. Todd Henry GSU
More informationExploring the giant planet - brown dwarf connection with astrometry. Johannes Sahlmann ESA Research Fellow at ESAC
Exploring the giant planet - brown dwarf connection with astrometry ESA Research Fellow at ESAC Who s Who, Paris - 2 July 215 IS MASS A GOOD DEMOGRAPHIC INDICATOR? 2MASSWJ127334 393254 first image of a
More informationAstro 1050 Mon. Apr. 3, 2017
Astro 1050 Mon. Apr. 3, 017 Today: Chapter 15, Surveying the Stars Reading in Bennett: For Monday: Ch. 15 Surveying the Stars Reminders: HW CH. 14, 14 due next monday. 1 Chapter 1: Properties of Stars
More informationExtrasolar planets. Lecture 23, 4/22/14
Extrasolar planets Lecture 23, 4/22/14 Extrasolar planets Extrasolar planets: planets around other stars Also called exoplanets 1783 exoplanets discovered as of 4/21/14 Orbitting 1105 different stars Number
More informationReading and Announcements. Read Chapters 8.3, 11.5, 12.1 Quiz #5, Thursday, March 21 Homework #5 due Tuesday, March 19
Reading and Announcements Read Chapters 8.3, 11.5, 12.1 Quiz #5, Thursday, March 21 Homework #5 due Tuesday, March 19 Measurements of Star Properties Apparent brightness Direct measurement Parallax Distance
More informationMeasuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam]
Measuring the Properties of Stars (ch. 17) [Material in smaller font on this page will not be present on the exam] Although we can be certain that other stars are as complex as the Sun, we will try to
More informationThe HR Diagram. L f 2 L d2 N obj V d 3 N obj L3/2. Most (>90%) stars lie
The HR Diagram Most (>90%) stars lie on the main sequence. A few stars are cool and extremely bright, so, by L = 4 π R 2 σ T 4, they must be extremely large. A few stars are hot, but extremely faint, so
More informationAsterseismology and Gaia
Asterseismology and Gaia Asteroseismology can deliver accurate stellar radii and masses Huber et al 2017 compare results on distances from Gaia and asteroseismology for 2200 Kepler stars Asteroseismology
More informationMy 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 informationGet ready for quiz # 5! Get out a ½ sheet and Calculator
Get ready for quiz # 5! Get out a ½ sheet and Calculator The above image shows the solar eclipse earlier this month as covered and uncovered by several different solar observatories. The innermost image
More informationPlanets are plentiful
Extra-Solar Planets Planets are plentiful The first planet orbiting another Sun-like star was discovered in 1995. We now know of 209 (Feb 07). Including several stars with more than one planet - true planetary
More informationBased 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 information3.4 Transiting planets
64 CHAPTER 3. TRANSITS OF PLANETS: MEAN DENSITIES 3.4 Transiting planets A transits of a planet in front of its parent star occurs if the line of sight is very close to the orbital plane. The transit probability
More informationThe Main Point(s) Lecture #36: Planets Around Other Stars. Extrasolar Planets! Reading: Chapter 13. Theory Observations
Lecture #36: Planets Around Other Stars Extrasolar Planets! Theory Observations Detection methods Results to date... Implications for "Habitable Zones" Reading: Chapter 13 Astro 102/104 1 The Main Point(s)
More informationTypes of Stars 1/31/14 O B A F G K M. 8-6 Luminosity. 8-7 Stellar Temperatures
Astronomy 113 Dr. Joseph E. Pesce, Ph.D. The Nature of Stars For nearby stars - measure distances with parallax 1 AU d p 8-2 Parallax A January ³ d = 1/p (arcsec) [pc] ³ 1pc when p=1arcsec; 1pc=206,265AU=3
More informationThe magnitude system. ASTR320 Wednesday January 30, 2019
The magnitude system ASTR320 Wednesday January 30, 2019 What we measure: apparent brightness How bright a star appears to be in the sky depends on: How bright it actually is Luminosity and its distance
More information