5. Cosmic Distance Ladder Ii: Standard Candles
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Divinus Lux Observatory Bulletin: Report #28 100 Dave Arnold
Vol. 9 No. 2 April 1, 2013 Journal of Double Star Observations Page Journal of Double Star Observations VOLUME 9 NUMBER 2 April 1, 2013 Inside this issue: Using VizieR/Aladin to Measure Neglected Double Stars 75 Richard Harshaw BN Orionis (TYC 126-0781-1) Duplicity Discovery from an Asteroidal Occultation by (57) Mnemosyne 88 Tony George, Brad Timerson, John Brooks, Steve Conard, Joan Bixby Dunham, David W. Dunham, Robert Jones, Thomas R. Lipka, Wayne Thomas, Wayne H. Warren Jr., Rick Wasson, Jan Wisniewski Study of a New CPM Pair 2Mass 14515781-1619034 96 Israel Tejera Falcón Divinus Lux Observatory Bulletin: Report #28 100 Dave Arnold HJ 4217 - Now a Known Unknown 107 Graeme L. White and Roderick Letchford Double Star Measures Using the Video Drift Method - III 113 Richard L. Nugent, Ernest W. Iverson A New Common Proper Motion Double Star in Corvus 122 Abdul Ahad High Speed Astrometry of STF 2848 With a Luminera Camera and REDUC Software 124 Russell M. Genet TYC 6223-00442-1 Duplicity Discovery from Occultation by (52) Europa 130 Breno Loureiro Giacchini, Brad Timerson, Tony George, Scott Degenhardt, Dave Herald Visual and Photometric Measurements of a Selected Set of Double Stars 135 Nathan Johnson, Jake Shellenberger, Elise Sparks, Douglas Walker A Pixel Correlation Technique for Smaller Telescopes to Measure Doubles 142 E. O. Wiley Double Stars at the IAU GA 2012 153 Brian D. Mason Report on the Maui International Double Star Conference 158 Russell M. Genet International Association of Double Star Observers (IADSO) 170 Vol. 9 No. 2 April 1, 2013 Journal of Double Star Observations Page 75 Using VizieR/Aladin to Measure Neglected Double Stars Richard Harshaw Cave Creek, Arizona [email protected] Abstract: The VizierR service of the Centres de Donnes Astronomiques de Strasbourg (France) offers amateur astronomers a treasure trove of resources, including access to the most current version of the Washington Double Star Catalog (WDS) and links to tens of thousands of digitized sky survey plates via the Aladin Java applet. -
Plotting Variable Stars on the H-R Diagram Activity
Pulsating Variable Stars and the Hertzsprung-Russell Diagram The Hertzsprung-Russell (H-R) Diagram: The H-R diagram is an important astronomical tool for understanding how stars evolve over time. Stellar evolution can not be studied by observing individual stars as most changes occur over millions and billions of years. Astrophysicists observe numerous stars at various stages in their evolutionary history to determine their changing properties and probable evolutionary tracks across the H-R diagram. The H-R diagram is a scatter graph of stars. When the absolute magnitude (MV) – intrinsic brightness – of stars is plotted against their surface temperature (stellar classification) the stars are not randomly distributed on the graph but are mostly restricted to a few well-defined regions. The stars within the same regions share a common set of characteristics. As the physical characteristics of a star change over its evolutionary history, its position on the H-R diagram The H-R Diagram changes also – so the H-R diagram can also be thought of as a graphical plot of stellar evolution. From the location of a star on the diagram, its luminosity, spectral type, color, temperature, mass, age, chemical composition and evolutionary history are known. Most stars are classified by surface temperature (spectral type) from hottest to coolest as follows: O B A F G K M. These categories are further subdivided into subclasses from hottest (0) to coolest (9). The hottest B stars are B0 and the coolest are B9, followed by spectral type A0. Each major spectral classification is characterized by its own unique spectra. -
The Impact of the Astro2010 Recommendations on Variable Star Science
The Impact of the Astro2010 Recommendations on Variable Star Science Corresponding Authors Lucianne M. Walkowicz Department of Astronomy, University of California Berkeley [email protected] phone: (510) 642–6931 Andrew C. Becker Department of Astronomy, University of Washington [email protected] phone: (206) 685–0542 Authors Scott F. Anderson, Department of Astronomy, University of Washington Joshua S. Bloom, Department of Astronomy, University of California Berkeley Leonid Georgiev, Universidad Autonoma de Mexico Josh Grindlay, Harvard–Smithsonian Center for Astrophysics Steve Howell, National Optical Astronomy Observatory Knox Long, Space Telescope Science Institute Anjum Mukadam, Department of Astronomy, University of Washington Andrej Prsa,ˇ Villanova University Joshua Pepper, Villanova University Arne Rau, California Institute of Technology Branimir Sesar, Department of Astronomy, University of Washington Nicole Silvestri, Department of Astronomy, University of Washington Nathan Smith, Department of Astronomy, University of California Berkeley Keivan Stassun, Vanderbilt University Paula Szkody, Department of Astronomy, University of Washington Science Frontier Panels: Stars and Stellar Evolution (SSE) February 16, 2009 Abstract The next decade of survey astronomy has the potential to transform our knowledge of variable stars. Stellar variability underpins our knowledge of the cosmological distance ladder, and provides direct tests of stellar formation and evolution theory. Variable stars can also be used to probe the fundamental physics of gravity and degenerate material in ways that are otherwise impossible in the laboratory. The computational and engineering advances of the past decade have made large–scale, time–domain surveys an immediate reality. Some surveys proposed for the next decade promise to gather more data than in the prior cumulative history of astronomy. -
Distances and Magnitudes Distance Measurements the Cosmic Distance
Distances and Magnitudes Prof Andy Lawrence Astronomy 1G 2011-12 Distance Measurements Astronomy 1G 2011-12 The cosmic distance ladder • Distance measurements in astronomy are a chain, with each type of measurement relative to the one before • The bottom rung is the Astronomical Unit (AU), the (mean) distance between the Earth and the Sun • Many distance estimates rely on the idea of a "standard candle" or "standard yardstick" Astronomy 1G 2011-12 Distances in the solar system • relative distances to planets given by periods + Keplers law (see Lecture-2) • distance to Venus measured by radar • Sun-Earth = 1 A.U. (average) • Sun-Jupiter = 5 A.U. (average) • Sun-Neptune = 30 A.U. (average) • Sun- Oort cloud (comets) ~ 50,000 A.U. • 1 A.U. = 1.496 x 1011 m Astronomy 1G 2011-12 Distances to nearest stars • parallax against more distant non- moving stars • 1 parsec (pc) is defined as distance where parallax = 1 second of arc in standard units D = a/✓ (radians, metres) in AU and arcsec D(AU) = 1/✓rad = 206, 265/✓00 in parsec and arcsec D(pc) = 1/✓00 nearest star Proxima Centauri 1.30pc Very hard to measure less than 0.1" 1pc = 206,265 AU = 3.086 x 1016m so only good for stars a few parsecs away... until launch of GAIA mission in 2014..... Astronomy 1G 2011-12 More distant stars : standard candle technique If a star has luminosity L (total energy emitted per sec) then at L distance D we will observe flux density F (i.e. energy per second F = 2 per sq.m. -
Standard Candles in Cosmology
Standard Candles: Distance Measurement in Astronomy Farley V. Ferrante Southern Methodist University 5/3/2017 PHYS 3368: Principles of Astrophysics & Cosmology 1 OUTLINE • Cosmic Distance Ladder • Standard Candles Parallax Cepheid variables Planetary nebula Most luminous supergiants Most luminous globular clusters Most luminous H II regions Supernovae Hubble constant & red shift • Standard Model of Cosmology 5/3/2017 PHYS 3368: Principles of Astrophysics & Cosmology 2 The Cosmic Distance Ladder - Distances far too vast to be measured directly - Several methods of indirect measurement - Clever methods relying on careful observation and basic mathematics - Cosmic distance ladder: A progression of indirect methods which scale, overlap, & calibrate parameters for large distances in terms of smaller distances • More methods calibrate these distances until distances that can be measured directly are achieved 5/3/2017 PHYS 3368: Principles of Astrophysics & Cosmology 3 Standard Candles • Magnitude: Historical unit (Hipparchus) of stellar brightness such that 5 magnitudes represents a factor of 100 in intensity • Apparent magnitude: Number assigned to visual brightness of an object; originally a scale of 1-6 • Absolute magnitude: Magnitude an object would have at 10 pc (convenient distance for comparison) • List of most luminous stars 5/3/2017 PHYS 3368: Principles of Astrophysics & Cosmology 4 5/3/2017 PHYS 3368: Principles of Astrophysics & Cosmology 5 The Cosmic Distance Ladder 5/3/2017 PHYS 3368: Principles of Astrophysics & Cosmology 6 The -
KEPLER-21B: a 1.6 Rearth PLANET TRANSITING the BRIGHT OSCILLATING F SUBGIANT STAR HD 179070 Steve B
The Astrophysical Journal, 746:123 (18pp), 2012 February 20 doi:10.1088/0004-637X/746/2/123 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. ∗ KEPLER-21b: A 1.6 REarth PLANET TRANSITING THE BRIGHT OSCILLATING F SUBGIANT STAR HD 179070 Steve B. Howell1,2,36, Jason F. Rowe2,3,36, Stephen T. Bryson2, Samuel N. Quinn4, Geoffrey W. Marcy5, Howard Isaacson5, David R. Ciardi6, William J. Chaplin7, Travis S. Metcalfe8, Mario J. P. F. G. Monteiro9, Thierry Appourchaux10, Sarbani Basu11, Orlagh L. Creevey12,13, Ronald L. Gilliland14, Pierre-Olivier Quirion15, Denis Stello16, Hans Kjeldsen17,Jorgen¨ Christensen-Dalsgaard17, Yvonne Elsworth7, Rafael A. Garc´ıa18, Gunter¨ Houdek19, Christoffer Karoff7, Joanna Molenda-Zakowicz˙ 20, Michael J. Thompson8, Graham A. Verner7,21, Guillermo Torres4, Francois Fressin4, Justin R. Crepp23, Elisabeth Adams4, Andrea Dupree4, Dimitar D. Sasselov4, Courtney D. Dressing4, William J. Borucki2, David G. Koch2, Jack J. Lissauer2, David W. Latham4, Lars A. Buchhave22,35, Thomas N. Gautier III24, Mark Everett1, Elliott Horch25, Natalie M. Batalha26, Edward W. Dunham27, Paula Szkody28,36, David R. Silva1,36, Ken Mighell1,36, Jay Holberg29,36,Jeromeˆ Ballot30, Timothy R. Bedding16, Hans Bruntt12, Tiago L. Campante9,17, Rasmus Handberg17, Saskia Hekker7, Daniel Huber16, Savita Mathur8, Benoit Mosser31, Clara Regulo´ 12,13, Timothy R. White16, Jessie L. Christiansen3, Christopher K. Middour32, Michael R. Haas2, Jennifer R. Hall32,JonM.Jenkins3, Sean McCaulif32, Michael N. Fanelli33, Craig -
The Kepler Characterization of the Variability Among A- and F-Type Stars I
A&A 534, A125 (2011) Astronomy DOI: 10.1051/0004-6361/201117368 & c ESO 2011 Astrophysics The Kepler characterization of the variability among A- and F-type stars I. General overview K. Uytterhoeven1,2,3,A.Moya4, A. Grigahcène5,J.A.Guzik6, J. Gutiérrez-Soto7,8,9, B. Smalley10, G. Handler11,12, L. A. Balona13,E.Niemczura14, L. Fox Machado15,S.Benatti16,17, E. Chapellier18, A. Tkachenko19, R. Szabó20, J. C. Suárez7,V.Ripepi21, J. Pascual7, P. Mathias22, S. Martín-Ruíz7,H.Lehmann23, J. Jackiewicz24,S.Hekker25,26, M. Gruberbauer27,11,R.A.García1, X. Dumusque5,28,D.Díaz-Fraile7,P.Bradley29, V. Antoci11,M.Roth2,B.Leroy8, S. J. Murphy30,P.DeCat31, J. Cuypers31, H. Kjeldsen32, J. Christensen-Dalsgaard32 ,M.Breger11,33, A. Pigulski14, L. L. Kiss20,34, M. Still35, S. E. Thompson36,andJ.VanCleve36 (Affiliations can be found after the references) Received 30 May 2011 / Accepted 29 June 2011 ABSTRACT Context. The Kepler spacecraft is providing time series of photometric data with micromagnitude precision for hundreds of A-F type stars. Aims. We present a first general characterization of the pulsational behaviour of A-F type stars as observed in the Kepler light curves of a sample of 750 candidate A-F type stars, and observationally investigate the relation between γ Doradus (γ Dor), δ Scuti (δ Sct), and hybrid stars. Methods. We compile a database of physical parameters for the sample stars from the literature and new ground-based observations. We analyse the Kepler light curve of each star and extract the pulsational frequencies using different frequency analysis methods. -
New Globular Cluster Age Estimates and Constraints on the Cosmic Equation of State and the Matter Density of the Universe
1 New Globular Cluster Age Estimates and Constraints on the Cosmic Equation of State and The Matter Density of the Universe. Lawrence M. Krauss* & Brian Chaboyer *Departments of Physics and Astronomy, Case Western Reserve University, 10900 Euclid Ave., Cleveland OH USA 44106-7079; Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH. USA New estimates of globular cluster distances, combined with revised ranges for input parameters in stellar evolution codes and recent estimates of the earliest redshift of cluster formation allow us to derive a new 95% confidence level lower limit on the age of the Universe of 11 Gyr. This is now definitively inconsistent with the expansion age for a flat Universe for the currently allowed range of the Hubble constant unless the cosmic equation of state is dominated by a component that violates the strong energy condition. This solidifies the case for a dark energy-dominated universe, complementing supernova data and direct measurements of the geometry and matter density in the Universe. The best-fit age is consistent with a cosmological constant-dominated (w=pressure/energy density = -1) universe. For the Hubble Key project best fit value of the Hubble Ω Constant our age limits yields the constraints w < -0.4 and Ωmatter < 0.38 at the 68 Ω % confidence level, and w < -0.26 and Ωmatter < 0.58 at the 95 % confidence level. Age determinations of globular clusters provided one of the earliest motivations for considering the possible existence of a cosmological constant. By comparing a lower limit on the age of the oldest globular clusters in our galaxy--- estimated in the 1980 s to be 15-20 Gyr---with the expansion age, determined by measurements of the Hubble constant, an apparent inconsistency arose: globular clusters appeared to be older than 2 the Universe unless one allowed for a possible Cosmological Constant. -
Exoplanet Community Report
JPL Publication 09‐3 Exoplanet Community Report Edited by: P. R. Lawson, W. A. Traub and S. C. Unwin National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California March 2009 The work described in this publication was performed at a number of organizations, including the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Publication was provided by the Jet Propulsion Laboratory. Compiling and publication support was provided by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, or the Jet Propulsion Laboratory, California Institute of Technology. © 2009. All rights reserved. The exoplanet community’s top priority is that a line of probeclass missions for exoplanets be established, leading to a flagship mission at the earliest opportunity. iii Contents 1 EXECUTIVE SUMMARY.................................................................................................................. 1 1.1 INTRODUCTION...............................................................................................................................................1 1.2 EXOPLANET FORUM 2008: THE PROCESS OF CONSENSUS BEGINS.....................................................2 -
The Ellipticities of Globular Clusters in the Andromeda Galaxy
ASTRONOMY & ASTROPHYSICS MAY I 1996, PAGE 447 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 116, 447-461 (1996) The ellipticities of globular clusters in the Andromeda galaxy A. Staneva1, N. Spassova2 and V. Golev1 1 Department of Astronomy, Faculty of Physics, St. Kliment Okhridski University of Sofia, 5 James Bourchier street, BG-1126 Sofia, Bulgaria 2 Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tsarigradsko chauss´ee, BG-1784 Sofia, Bulgaria Received March 15; accepted October 4, 1995 Abstract. — The projected ellipticities and orientations of 173 globular clusters in the Andromeda galaxy have been determined by using isodensity contours and 2D Gaussian fitting techniques. A number of B plates taken with the 2 m Ritchey-Chretien-coud´e reflector of the Bulgarian National Astronomical Observatory were digitized and processed for each cluster. The derived ellipticities and orientations are presented in the form of a catalogue?. The projected ellipticities of M 31 GCs lie between 0.03 0.24 with mean valueε ¯=0.086 0.038. It may be concluded that the most globular clusters in the Andromeda galaxy÷ are quite spherical. The derived± orientations do not show a preference with respect to the center of M 31. Some correlations of the ellipticity with other clusters parameters are discussed. The ellipticities determined in this work are compared with those in other Local Group galaxies. Key words: globular clusters: general — galaxies: individual: M 31 — galaxies: star clusters — catalogs 1. Introduction Bergh & Morbey (1984), and Kontizas et al. (1989), have shown that the globulars in LMC are markedly more ellip- Representing the oldest of all stellar populations, the glo- tical than those in our Galaxy. -
Searching for RR Lyrae Stars in M15
Searching for RR Lyrae Stars in M15 ARCC Scholar thesis in partial fulfillment of the requirements of the ARCC Scholar program Khalid Kayal February 1, 2013 Abstract The expansion and contraction of an RR Lyrae star provides a high level of interest to research in astronomy because of the several intrinsic properties that can be studied. We did a systematic search for RR Lyrae stars in the globular cluster M15 using the Catalina Real-time Transient Survey (CRTS). The CRTS searches for rapidly moving Near Earth Objects and stationary optical transients. We created an algorithm to create a hexagonal tiling grid to search the area around a given sky coordinate. We recover light curve plots that are produced by the CRTS and, using the Lafler-Kinman search algorithm, we determine the period, which allows us to identify RR Lyrae stars. We report the results of this search. i Glossary of Abbreviations and Symbols CRTS Catalina Real-time Transient Survey RR A type of variable star M15 Messier 15 RA Right Ascension DEC Declination RF Radio frequency GC Globular cluster H-R Hertzsprung-Russell SDSS Sloan Digital Sky Survey CCD Couple-Charged Device Photcat DB Photometry Catalog Database FAP False Alarm Probability ii Contents 1 Introduction 1 2 Background on RR Lyrae Stars 5 2.1 What are RR Lyraes? . 5 2.2 Types of RR Lyrae Stars . 6 2.3 Stellar Evolution . 8 2.4 Pulsating Mechanism . 9 3 Useful Tools and Surveys 10 3.1 Choosing M15 . 10 3.2 Catalina Real-time Transient Survey . 11 3.3 The Sloan Digital Sky Survey . -
Astronomy (ASTR) 1
Astronomy (ASTR) 1 ASTR 330 The Cosmic Distance Scale 3 Credit Hours ASTRONOMY (ASTR) An exploration of the cosmic distance ladder focusing on the systems and techniques that astronomers use in establishing the distances to ASTR 130 Introduction to Astronomy 3 Credit Hours celestial objects. Direct measures using radar ranging and trigonometric A one-term introduction for those interested in learning about the present parallax will be discussed for objects in the solar system and for stars state of knowledge of the Universe, its origin, evolution, organization, within about 3000 light-years of the Sun, respectively. For more remote and ultimate fate. Exciting new discoveries concerning extrasolar systems in or just outside the Milky Way, methods based spectroscopic planets, star birth, supermassive black holes, dark matter/dark energy, parallax and the period-luminosity relation for various types of variable and cosmology are discussed. Two years of high school math or its stars will be introduced. For the extra-galactic objects, use of the Hubble equivalent recommended. relation and the light curves of Type Ia supernovae will be made to assess ASTR 131 Introductory Astronomy Lab 1 Credit Hour the distances. At each rung of the ladder, emphasis will be placed on the An introduction to some of the important observational techniques and astrophysical principles and processes underlying the methodology being analytical methods used by astronomers. Ground-based and satellite applied. 3 hours lecture data will be used to reveal physical and chemical properties of the moon, Prerequisite(s): (MATH 113 or MATH 115) and (PHYS 126 or PHYS 151) planets, stars, and the Milky Way.