DOCSLIB.ORG

Sun's Gravity Bends Starlight

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sun's Gravity Bends Starlight National Aeronautics and Space Administration Age of the Universe: Size of the Universe: Infinite 300,000 Light Years Cosmic1919 Times MT. WILSON ASTRONOMER ESTIMATES SUN’S GRAVITY BENDS STARLIGHT MILKY WAY TEN TIMES BIGGER THAN THOUGHT Einstein’s Theory Triumphs But Disputes Suggestions that Spiral Nebulae are Other “Island Universes” “One of the greatest—perhaps the great- actly as arranged, but out of the 16 plates taken, The Milky Way is a “discoidal” (disc-shaped) Dr. Shapley has concluded that “our galactic est—of achievements in the history of human only two showed as many as five stars each. galaxy of stars 10 times bigger than astronomers universe appears as a single, enormous, all-com- thought” was what Sir Joseph Thomson, Presi- Prof. Eddington was also unable to stay several had previously conceived, according to Mt. Wil- prehending unit, the extent and form of which dent of the Royal Society of London, called Dr. more months to take check-photographs of the son astronomer, Dr. Harlow Shapley. Moreover, seem to be indicated through the dimensions of Albert Einstein’s prediction, which was appar- star field. he claims, the Sun exists nearer to its edge than the widely extended assemblage of globular clus- ently verified during the total eclipse of the Sun Sir Frank explained in detail the apparatus to its center. But he disputes the hypotheses of ters.” The center of our discoidal sidereal system May 29 last. both expeditions had employed, the way the other astronomers that scores of spiral nebulae “is distant from the Earth some twenty thousand Sir Joseph made his pronouncement during photographic plates were measured back at the seen in the starry heavens are other galaxies, parsecs”—more than 60,000 light-years—“in the a discussion of the results from observations of Greenwich Observatory, the corrections that had or “island universes”, that resemble the Milky direction of the constellation Sagittarius,” Dr. the solar eclipse at a joint meeting of the Roy- to be made for various disturbing factors, and the Way. Shapley continued. al Society and the Royal Astronomical Society methods by which comparison between the the- In his tour-de-force series of papers through- His conclusions fly in the face of generally ac- in London on Thursday evening, November 6, oretical and observed positions had been made. out 1918 and 1919, the prolific Dr. Shapley ex- cepted astronomical wisdom. “Until the last year before a large attendance of astronomers and He convinced the meeting that the results were amines other recent astronomical work in aston- or so, most students of stellar problems believed physicists. The excitement in the air was almost definite and conclusive, and that deflection did ishing detail, as well as presenting the results of rather vaguely that the Sun was not far from the palpable as it seemed generally accepted that take place. He also asserted that the measure- his own astronomical photography using the 60- center of the universe, and that the radius of the the observations were decisive in verifying the ments showed that the extent of the deflection inch reflector of the Mount Wilson Observatory galactic system was of the order of 1,000 par- prediction of Dr. Einstein, Professor of Physics was in close accord with the theoretical amount in southern California. His particular subject of secs,” he said (1,000 parsecs is more than 3,000 at the University of Berlin and Director of the predicted by Dr. Einstein, as opposed to half of interest is globular star clusters—nearly spheri- light-years). Some astronomers thought the Kaiser Wilhelm Physical Institute. that amount, the amount that would follow if the cal clusters of hundreds of stars that have long galactic system might be as large as 10,000 to principles of Newton were correct. puzzled astronomers because of their peculiar 20,000 light-years across. But according to Dr. The prediction “After a careful study of the plates I am pre- positions in only certain parts of the sky. When Shapley, the positions of globular clusters in the According to the gravitational principles pared to say that there can be no doubt that they Dr. Shapley began his study in 1914, 69 globular arrangement of sidereal objects suggest “that the enunciated by Sir Isaac Newton in his classic confirm Einstein’s prediction,” Sir Frank de- clusters were known; by the time he completed actual diameter of the galactic system is of the work Optics some two centuries ago, a ray of clared. “A very definite result has been obtained his work in 1918, he had added another 17 to the order of 100,000 parsecs”, This is a staggering light from a distant star just grazing across the that light is deflected in accordance with Ein- list. distance, larger than 300,000 light-years across, edge of a massive object should be bent by an stein’s law of gravitation.” In addition to pinpointing the exact position more than 10 times larger than any other astron- amount that depends on the object’s mass and “For the full effect that has been obtained, of each globular cluster in the sky, he also spread omer had hypothesized. thus its gravitational field. Newton thought of we must assume that gravity obeys the new law out their light into spectra to determine their mo- “This newer conception greatly embarrasses the gravity as a force that pulls things toward an ob- proposed by Einstein,” added Prof. Eddington. tions, specifically whether they were approach- interpretation of spirals as stellar organizations of a ject: the bigger the object, the stronger the pull. “This is one of the most crucial tests between ing the Sun or receding from it. From these data, size comparable to that of the Galaxy,” Dr. Shapley The most massive object in the vicinity of Newton’s law and the proposed new law.” Dr. Shapley sought to calculate the gravitation- said, because such a size would imply that the spi- the Earth is the Sun. So according to Newtonian al forces on the clusters, to learn whether they rals were inconceivable distances away in space. principles, a light ray from a distant star graz- WHY A TOTAL SOLAR ECLIPSE? were revolving around a common center, and if “For example,” he pointed out, “if any bright spiral so, the location of that center. He also sought to of 10 minutes of arc in angular measure has an ac- ing the edge of the Sun should be attracted or Herr Einstein in Berlin bent by the Sun’s gravity by an amount equal According to predictions by both Sir Isaac determine the distances of the globular clusters tual diameter directly comparable with that of the to 0.87 seconds of arc. To be sure, that angle is the Sun and the stars to be photographed at the Newton and Dr. Albert Einstein, a ray of light from the Sun using the novel method of Cepheid galactic system, its distance must be greater than a very small, about equivalent to a human hair at same time. from a star nearly behind the Sun (as seen from variables pioneered by Miss Henrietta Leavitt hundred million light-years.”. Similarly, the aver- 75 feet; but it is actually measurable on today’s Prof. Eddington himself decided to lead an Earth) will be deflected—bent toward the Sun— of Harvard Observatory. He also looked at ir- age proper motions suggested by the careful ob- astronomical photographic plates if adequate care expedition to the island of Principe, in the Gulf as it passes by the limb (edge) of the Sun. Such a regularly-shaped clusters of stars, the so-called servational measurements of several astronomers is taken. of Guinea close to the coast of West Africa, deflection would make the star look slightly far- “open clusters”, as well as other individual stars “would indicate appalling velocities in space.” Dr. Einstein’s general theory of relativity, near the end of the path of totality (see map). ther away from the edge of the Sun than it really and types of objects. In short, Dr. Shapley concludes, many observa- however, conceives of gravitation as indistinguish- He also convinced the Astronomer Royal—Sir is. After four years of diligent study, often assisted by tions “all seem definitely to oppose the “island uni- able from inertia. The “force” of gravity one feels Frank Dyson, Director of the Royal Observato- Dr. Einstein’s theory of relativity, however, his wife Martha B. Shapley, Dr. Shapley has pub- verse” hypothesis of the spiral nebulae.” pressing one down into a chair is the same as the ry, Greenwich—to send another expedition else- predicts that the amount of the deflection should lished a number of astonishing conclusions. “force” one feels when pulled forward in an auto- where, to minimize the chances of clouds inter- be double that predicted by Newtonian mechan- mobile when the driver brakes. fering with the observations. Led by Dr. Andrew ics. The maximum shift, for a star whose ray of According to Dr. Einstein, gravity, like in- Crommelin from the Royal Observatory, it set light just grazes the limb of the Sun, would be 1.75 ertia, doesn’t pull. Instead, a mass warps or up instruments at Sobral in northern Brazil, near seconds of arc, twice the amount Newton predicted EXPANDING OR CONTRACTING? curves space and time surrounding the object. the beginning of the path of totality. (0.87 arcsecond). The apparent positions of stars Einstein’s Theory Predicts Universe Must be Doing One or the Other The amount of curvature is proportional to the At each of these places, if the weather were pro- closer to the Sun’s limb would be shifted more than amount of mass.
Load more

Recommended publications
  • Pdf/44/4/905/5386708/44-4-905.Pdf
    MI-TH-214 INT-PUB-21-004 Axions: From Magnetars and Neutron Star Mergers to Beam Dumps and BECs Jean-François Fortin∗ Département de Physique, de Génie Physique et d’Optique, Université Laval, Québec, QC G1V 0A6, Canada Huai-Ke Guoy and Kuver Sinhaz Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA Steven P. Harrisx Institute for Nuclear Theory, University of Washington, Seattle, WA 98195, USA Doojin Kim{ Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA Chen Sun∗∗ School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel (Dated: February 26, 2021) We review topics in searches for axion-like-particles (ALPs), covering material that is complemen- tary to other recent reviews. The first half of our review covers ALPs in the extreme environments of neutron star cores, the magnetospheres of highly magnetized neutron stars (magnetars), and in neu- tron star mergers. The focus is on possible signals of ALPs in the photon spectrum of neutron stars and gravitational wave/electromagnetic signals from neutron star mergers. We then review recent developments in laboratory-produced ALP searches, focusing mainly on accelerator-based facilities including beam-dump type experiments and collider experiments. We provide a general-purpose discussion of the ALP search pipeline from production to detection, in steps, and our discussion is straightforwardly applicable to most beam-dump type and reactor experiments. We end with a selective look at the rapidly developing field of ultralight dark matter, specifically the formation of Bose-Einstein Condensates (BECs).
    [Show full text]
  • The Twenty−Eight Lunar Mansions of China
    浜松医科大学紀要 一般教育 第5号（1991） THE TWENTY－EIGHT LUNAR MANSIONS OF CHINA （中国の二十八宿） David B． Kelley （英 語〉 Abstract： This’Paper attempts to place the development of the Chinese system ・fTw・nty－Eight Luna・ Man・i・n・（；＋八宿）i・・血・lti－cult・・al f・am・w・・k， withi・ which， contributions from cultures outside of China may be recognized． lt・ system－ atically compares the Chinese system with similar systems from Babylonia， Arabia，・ and lndia． The results of such a comparison not only suggest an early date for its development， but also a significant level of input from， most likely， a Middle Eastern source． Significantly， the data suggest an awareness， on the part of the ancient Chinese， of completely arbitrary groupings of stars （the twelve constellations of the Middle Eastern Zodiac）， as well as their equally arbitrary syMbolic associ－ ations． The paper also attempts to elucidate the graphic and organizational relation－ ship between the Chinese system of lunar mansions and （1．） Phe twelve Earthly Branches（地支）and（2．）the ten Heavenly S．tems（天干）． key words二China， Lunar calender， Lunar mansions， Zodiac． O． INTRODUCTION The time it takes the Moon to circle the Earth is 29 days， 12 hours， and 44 minutes． However， the time it takes the moon to return to the same （fixed一） star position amounts to some 28 days． ln China， it is the latter period that was and is of greater significance． The Erh－Shih－Pα一Hsui（一Kung）， the Twenty－Eight－lnns（Mansions），二十八 宿（宮），is the usual term in（Mandarin）Chinese， and includes 28 names for each day of such a month． ln East Asia， what is not
    [Show full text]
  • College of San Mateo Observatory Stellar Spectra Catalog ______
    College of San Mateo Observatory Stellar Spectra Catalog SGS Spectrograph Spectra taken from CSM observatory using SBIG Self Guiding Spectrograph (SGS) ___________________________________________________ A work in progress compiled by faculty, staff, and students. Stellar Spectroscopy Stars are divided into different spectral types, which result from varying atomic-level activity on the star, due to its surface temperature. In spectroscopy, we measure this activity via a spectrograph/CCD combination, attached to a moderately sized telescope. The resultant data are converted to graphical format for further analysis. The main spectral types are characterized by the letters O,B,A,F,G,K, & M. Stars of O type are the hottest, as well as the rarest. Stars of M type are the coolest, and by far, the most abundant. Each spectral type is also divided into ten subtypes, ranging from 0 to 9, further delineating temperature differences. Type Temperature Color O 30,000 - 60,000 K Blue B 10,000 - 30,000 K Blue-white A 7,500 - 10,000 K White F 6,000 - 7,500 K Yellow-white G 5,000 - 6,000 K Yellow K 3,500 - 5,000 K Yellow-orange M >3,500 K Red Class Spectral Lines O -Weak neutral and ionized Helium, weak Hydrogen, a relatively smooth continuum with very few absorption lines B -Weak neutral Helium, stronger Hydrogen, an otherwise relatively smooth continuum A -No Helium, very strong Hydrogen, weak CaII, the continuum is less smooth because of weak ionized metal lines F -Strong Hydrogen, strong CaII, weak NaI, G-band, the continuum is rougher because of many ionized metal lines G -Weaker Hydrogen, strong CaII, stronger NaI, many ionized and neutral metals, G-band is present K -Very weak Hydrogen, strong CaII, strong NaI and many metals G- band is present M -Strong TiO molecular bands, strongest NaI, weak CaII very weak Hydrogen absorption.
    [Show full text]
  • Search for Long-Duration Transient Gravitational Waves Associated with Magnetar Bursts During Ligo’S Sixth Science Run
    SEARCH FOR LONG-DURATION TRANSIENT GRAVITATIONAL WAVES ASSOCIATED WITH MAGNETAR BURSTS DURING LIGO’S SIXTH SCIENCE RUN by RYAN QUITZOW-JAMES A DISSERTATION Presented to the Department of Physics and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy March 2016 DISSERTATION APPROVAL PAGE Student: Ryan Quitzow-James Title: Search for Long-Duration Transient Gravitational Waves Associated with Magnetar Bursts during LIGO’s Sixth Science Run This dissertation has been accepted and approved in partial fulfillment of the requirements for the Doctor of Philosophy degree in the Department of Physics by: James E. Brau Chair Raymond E. Frey Advisor Timothy Cohen Core Member Daniel A. Steck Core Member James A. Isenberg Institutional Representative and Scott L. Pratt Dean of the Graduate School Original approval signatures are on file with the University of Oregon Graduate School. Degree awarded March 2016 ii © 2016 Ryan Quitzow-James This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs (United States) License. iii DISSERTATION ABSTRACT Ryan Quitzow-James Doctor of Philosophy Department of Physics March 2016 Title: Search for Long-Duration Transient Gravitational Waves Associated with Magnetar Bursts during LIGO’s Sixth Science Run Soft gamma repeaters (SGRs) and anomalous X-ray pulsars are thought to be neutron stars with strong magnetic fields, called magnetars, which emit intermittent bursts of hard X-rays and soft gamma rays. Three highly energetic bursts, known as giant flares, have been observed originating from three different SGRs, the latest and most energetic of which occurred on December 27, 2004, from the SGR with the largest estimated magnetic field, SGR 1806-20.
    [Show full text]
  • Chapter 16 the Sun and Stars
    Chapter 16 The Sun and Stars Stargazing is an awe-inspiring way to enjoy the night sky, but humans can learn only so much about stars from our position on Earth. The Hubble Space Telescope is a school-bus-size telescope that orbits Earth every 97 minutes at an altitude of 353 miles and a speed of about 17,500 miles per hour. The Hubble Space Telescope (HST) transmits images and data from space to computers on Earth. In fact, HST sends enough data back to Earth each week to fill 3,600 feet of books on a shelf. Scientists store the data on special disks. In January 2006, HST captured images of the Orion Nebula, a huge area where stars are being formed. HST’s detailed images revealed over 3,000 stars that were never seen before. Information from the Hubble will help scientists understand more about how stars form. In this chapter, you will learn all about the star of our solar system, the sun, and about the characteristics of other stars. 1. Why do stars shine? 2. What kinds of stars are there? 3. How are stars formed, and do any other stars have planets? 16.1 The Sun and the Stars What are stars? Where did they come from? How long do they last? During most of the star - an enormous hot ball of gas day, we see only one star, the sun, which is 150 million kilometers away. On a clear held together by gravity which night, about 6,000 stars can be seen without a telescope.
    [Show full text]
  • Binary Star Modeling: a Computational Approach
    TCNJ JOURNAL OF STUDENT SCHOLARSHIP VOLUME XIV APRIL 2012 BINARY STAR MODELING: A COMPUTATIONAL APPROACH Author: Daniel Silano Faculty Sponsor: R. J. Pfeiffer, Department of Physics ABSTRACT This paper illustrates the equations and computational logic involved in writing BinaryFactory, a program I developed in Spring 2011 in collaboration with Dr. R. J. Pfeiffer, professor of physics at The College of New Jersey. This paper outlines computational methods required to design a computer model which can show an animation and generate an accurate light curve of an eclipsing binary star system. The final result is a light curve fit to any star system using BinaryFactory. An example is given for the eclipsing binary star system TU Muscae. Good agreement with observational data was obtained using parameters obtained from literature published by others. INTRODUCTION This project started as a proposal for a simple animation of two stars orbiting one another in C++. I found that although there was software that generated simple animations of binary star orbits and generated light curves, the commercial software was prohibitively expensive or not very user friendly. As I progressed from solving the orbits to generating the Roche surface to generating a light curve, I learned much about computational physics. There were many trials along the way; this paper aims to explain to the reader how a computational model of binary stars is made, as well as how to avoid pitfalls I encountered while writing BinaryFactory. Binary Factory was written in C++ using the free C++ libraries, OpenGL, GLUT, and GLUI. A basis for writing a model similar to BinaryFactory in any language will be presented, with a light curve fit for the eclipsing binary star system TU Muscae in the final secion.
    [Show full text]
  • De-Coding Starlight (Grades 5-8)
    Teacher's Guide to Chandra X-ray Observatory From Pixels to Images: De-Coding Starlight (Grades 5-8) Background and Purpose In an effort to learn more about black holes, pulsars, supernovas, and other high-energy astronomical events, NASA launched the Chandra X-ray Observatory in 1999. Chandra is the largest space telescope ever launched and detects "invisible" X-ray radiation, which is often the only way that scientists can pinpoint and understand high-energy events in our universe. Computer aided data collection and processing is an essential facet to astronomical research using space- and ground-based telescopes. Every 8 hours, Chandra downloads millions of pieces of information to Earth. To control, process, and analyze this flood of numbers, scientists rely on computers, not only to do calculations, but also to change numbers into pictures. The final results of these analyses are wonderful and exciting images that expand understanding of the universe for not only scientists, but also decision-makers and the general public. Although computers are used extensively, scientists and programmers go through painstaking calibration and validation processes to ensure that computers produce technically correct images. As Dr. Neil Comins so eloquently states1, “These images create an impression of the glamour of science in the public mind that is not entirely realistic. The process of transforming [i.e., by using computers] most telescope data into accurate and meaningful images is long, involved, unglamorous, and exacting. Make a mistake in one of dozens of parameters or steps in the analysis and you will get inaccurate results.” The process of making the computer-generated images from X-ray data collected by Chandra involves the use of "false color." X-rays cannot be seen by human eyes, and therefore, have no "color." Visual representation of X-ray data, as well as radio, infrared, ultraviolet, and gamma, involves the use of "false color" techniques, where colors in the image represent intensity, energy, temperature, or another property of the radiation.
    [Show full text]
  • Archaeologic Inspection of the Milky Way Using Vibrations of a Fossil Seismic, Spectroscopic and Kinematic Characterization of a Binary Metal-Poor Halo Star
    Department of Physics and Astronomy Bachelor thesis in Physics, 15 credits Archaeologic inspection of the Milky Way using vibrations of a fossil Seismic, spectroscopic and kinematic characterization of a binary metal-poor Halo star Amanda Bystr¨om Supervisor: Marica Valentini Subject reader: Andreas Korn Examiner: Matthias Weiszflog Spring semester 2020 In collaboration with Leibniz-Institut fur¨ Astrophysik Potsdam Abstract - English The Milky Way has undergone several mergers with other galaxies during its lifetime. The mergers have been identified via stellar debris in the Halo of the Milky Way. The practice of mapping these mergers is called galactic ar- chaeology. To perform this archaeologic inspection, three stellar features must be mapped: chemistry, kinematics and age. Historically, the latter has been difficult to determine, but can today to high degree be determined through as- teroseismology. Red giants are well fit for these analyses. In this thesis, the red giant HE1405-0822 is completely characterized, using spectroscopy, asteroseis- mology and orbit integration, to map its origin. HE1405-0822 is a CEMP-r/s enhanced star in a binary system. Spectroscopy and asteroseismology are used in concert, iteratively to get precise stellar parameters, abundances and age. Its kinematics are analyzed, e.g. in action and velocity space, to see if it belongs to any known kinematical substructures in the Halo. It is shown that the mass accretion that HE1405-0822 has undergone has given it a seemingly younger age than probable. The binary probably transfered C- and s-process rich matter, but how it gained its r-process enhancement is still unknown. It also does not seem like the star comes from a known merger event based on its kinematics, and could possibly be a heated thick disk star.
    [Show full text]
  • Stellar Distances Teacher Guide
    Stars and Planets 1 TEACHER GUIDE Stellar Distances Our Star, the Sun In this Exploration, find out: ! How do the distances of stars compare to our scale model solar system?. ! What is a light year? ! How long would it take to reach the nearest star to our solar system? (Image Credit: NASA/Transition Region & Coronal Explorer) Note: The above image of the Sun is an X -ray view rather than a visible light image. Stellar Distances Teacher Guide In this exercise students will plan a scale model to explore the distances between stars, focusing on Alpha Centauri, the system of stars nearest to the Sun. This activity builds upon the activity Sizes of Stars, which should be done first, and upon the Scale in the Solar System activity, which is strongly recommended as a prerequisite. Stellar Distances is a math activity as well as a science activity. Necessary Prerequisite: Sizes of Stars activity Recommended Prerequisite: Scale Model Solar System activity Grade Level: 6-8 Curriculum Standards: The Stellar Distances lesson is matched to: ! National Science and Math Education Content Standards for grades 5-8. ! National Math Standards 5-8 ! Texas Essential Knowledge and Skills (grades 6 and 8) ! Content Standards for California Public Schools (grade 8) Time Frame: The activity should take approximately 45 minutes to 1 hour to complete, including short introductions and follow-ups. Purpose: To aid students in understanding the distances between stars, how those distances compare with the sizes of stars, and the distances between objects in our own solar system. © 2007 Dr Mary Urquhart, University of Texas at Dallas Stars and Planets 2 TEACHER GUIDE Stellar Distances Key Concepts: o Distances between stars are immense compared with the sizes of stars.
    [Show full text]
  • Neutron Stars & Black Holes
    Introduction ? Recall that White Dwarfs are the second most common type of star. ? They are the remains of medium-sized stars - hydrogen fused to helium Neutron Stars - failed to ignite carbon - drove away their envelopes to from planetary nebulae & - collapsed and cooled to form White Dwarfs ? The more massive a White Dwarf, the smaller its radius Black Holes ? Stars more massive than the Chandrasekhar limit of 1.4 solar masses cannot be White Dwarfs Formation of Neutron Stars As the core of a massive star (residual mass greater than 1.4 ?Supernova 1987A solar masses) begins to collapse: (arrow) in the Large - density quickly reaches that of a white dwarf Magellanic Cloud was - but weight is too great to be supported by degenerate the first supernova electrons visible to the naked eye - collapse of core continues; atomic nuclei are broken apart since 1604. by gamma rays - Almost instantaneously, the increasing density forces freed electrons to absorb electrons to form neutrons - the star blasts away in a supernova explosion leaving behind a neutron star. Properties of Neutron Stars Crab Nebula ? Neutrons stars predicted to have a radius of about 10 km ? In CE 1054, Chinese and a density of 1014 g/cm3 . astronomers saw a ? This density is about the same as the nucleus supernova ? A sugar-cube-sized lump of this material would weigh 100 ? Pulsar is at center (arrow) million tons ? It is very energetic; pulses ? The mass of a neutron star cannot be more than 2-3 solar are detectable at visual masses wavelengths ? Neutron stars are predicted to rotate very fast, to be very ? Inset image taken by hot, and have a strong magnetic field.
    [Show full text]
  • Research on Eclipsing Binary Star in Constellation of Taurus “WY Tau” Avery Mcchristian Advisor: Dr Shaukat Goderya
    Astronomy at Tarleton State University: A study of Eclipsing Binary Star (WY TAU) in the constellation of Taurus the Bull Avery McChristian Advisor: Dr Shaukat Goderya Types of Eclipsing Binary What is a Binary Star Stars Observation and Analysis A binary star is a stellar system consisting of two stars which The data on “WY TAU” was gathered in November and orbit around a common point, called the center of mass. The December of 2006 using Tarleton State’s observatory. two stars are gravitationally bound to each other. It has been Contact 1,008 images were collected over nine nights. The estimated that more than half of all stars in our galaxy are images were taken under two different filters; 507 were binary stars. Binary stars play a vital role in our taken using a Visual band pass filter and 501 were understanding of the evolution and physics of stars. When taken using a Blue band pass filter. Using “Astronomical studied they can provide important data on the mass of each Image Processing for Windows” software we were able individual star. It is possible to obtain this information only if Semi Detached to extract the Julian date and magnitude from the raw both spectroscopic and photometric study of the system is images. We then used excel to convert time, or Julian performed. Spectroscopic study enables the determination of date, into phase and magnitude into intensity. Using the absolute parameters of the binary system. phase and intensity figures we were able to construct the observed light curve. Upon inspection of the light curve we realized the period and epoch needed Detached corrections.
    [Show full text]
  • Gravity Tests with Radio Pulsars
    universe Review Gravity Tests with Radio Pulsars Norbert Wex 1,* and Michael Kramer 1,2 1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany; [email protected] 2 Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK * Correspondence: [email protected] Received: 19 August 2020; Accepted: 17 September 2020; Published: 22 September 2020 Abstract: The discovery of the first binary pulsar in 1974 has opened up a completely new field of experimental gravity. In numerous important ways, pulsars have taken precision gravity tests quantitatively and qualitatively beyond the weak-field slow-motion regime of the Solar System. Apart from the first verification of the existence of gravitational waves, binary pulsars for the first time gave us the possibility to study the dynamics of strongly self-gravitating bodies with high precision. To date there are several radio pulsars known which can be utilized for precision tests of gravity. Depending on their orbital properties and the nature of their companion, these pulsars probe various different predictions of general relativity and its alternatives in the mildly relativistic strong-field regime. In many aspects, pulsar tests are complementary to other present and upcoming gravity experiments, like gravitational-wave observatories or the Event Horizon Telescope. This review gives an introduction to gravity tests with radio pulsars and its theoretical foundations, highlights some of the most important results, and gives a brief outlook into the future of this important field of experimental gravity. Keywords: gravity; general relativity; pulsars 1.
    [Show full text]