The Astronomical Zoo: Discovery and Classification
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Chapter 3: Familiarizing Yourself with the Night Sky
Chapter 3: Familiarizing Yourself With the Night Sky Introduction People of ancient cultures viewed the sky as the inaccessible home of the gods. They observed the daily motion of the stars, and grouped them into patterns and images. They assigned stories to the stars, relating to themselves and their gods. They believed that human events and cycles were part of larger cosmic events and cycles. The night sky was part of the cycle. The steady progression of star patterns across the sky was related to the ebb and flow of the seasons, the cyclical migration of herds and hibernation of bears, the correct times to plant or harvest crops. Everywhere on Earth people watched and recorded this orderly and majestic celestial procession with writings and paintings, rock art, and rock and stone monuments or alignments. When the Great Pyramid in Egypt was constructed around 2650 BC, two shafts were built into it at an angle, running from the outside into the interior of the pyramid. The shafts coincide with the North-South passage of two stars important to the Egyptians: Thuban, the star closest to the North Pole at that time, and one of the stars of Orion’s belt. Orion was The Ishango Bone, thought to be a 20,000 year old associated with Osiris, one of the Egyptian gods of the lunar calendar underworld. The Bighorn Medicine Wheel in Wyoming, built by Plains Indians, consists of rocks in the shape of a large circle, with lines radiating from a central hub like the spokes of a bicycle wheel. -
Messier Objects
Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun. -
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. -
JESUITS, ROLE in GEOMAGNETISM That the Earth Does Not Rotate Because of Its Magnetic Field
Comp. by: DShiva Date:14/2/07 Time:15:55:17 Stage:First Proof File Path://spiina1001z/womat/production/ PRODENV/0000000005/0000001725/0000000022/000000A293.3D Proof by: QC by: J in which, in order to defend the geocentric system, he tried to show JESUITS, ROLE IN GEOMAGNETISM that the Earth does not rotate because of its magnetic field. Among the best observations made in China are those of Antoine Gaubil The Jesuits are members of a religious order of the Catholic Church, (1689–1759), who mentioned that the line of zero declination has with the Society of Jesus, founded in 1540 by Ignatius of Loyola. From time a movement from east to west. His observations and those of 1548, when Jesuits established their first college, their educational other Jesuits in China were published in France in three volumes work expanded rapidly and in the 18th century, in Europe alone, there between 1729 and 1732. In 1727, Nicolas Sarrabat (1698–1739) pub- were 645 colleges and universities and others in Asia and America. As lished Nouvelle hypothèse sur les variations de l’aiguille aimantée, an innovation in these colleges, special attention was given to teaching which was given an award by the Académie des Sciences of Paris. of mathematics, astronomy, and the natural sciences. This tradition has In 1769, Maximilian Hell (1720–1792), director of the observatory been continued in modern times in the many Jesuit colleges and uni- in Vienna, made observations of the magnetic declination during his versities and this tradition thus spread throughout the world. Jesuits’ journey to the island of Vardö in Lapland, at a latitude of 70 N, where interest in geomagnetism derived from teaching in these colleges he observed the transit of Venus over the solar disk. -
P. Angelo Segghi, S. J. 1818 - 18?8
P. ANGELO SEGGHI, S. J. 1818 - 18?8 H. A. BRUCK Pontifical Academician At this commemorative Colloquium which is devoted to "Spectral Classification of the Future" it is fitting that we should speak about the life and work of the man with whom all modern spectral classification started, Father Angelo Secchi who died here in Rome a hundred years ago in February I878. At the time of his death the name of Secchi was renowned throughout the scientific world, and his early death in his 60th year came as a great shock to the whole astronomical com munity - in the same way in which the untimely death of Father Treanor in February of this year is being deplored by astronomers all over the world. Father Secchi was one of the great pioneers of astro physics, or "physical astronomy" as he used to call it, whose work ranged over the widest possible field. He made fundamental contributions to solar physics as well as to stellar spectro scopy and he also worked with considerable success in geophysics and meterology. For 28 years of his life Father Secchi was in charge of the Observatory of the Collegio Romano, the Roman College of the Society of Jesus, an observatory which he transformed into one of the world's best known and most respected scientific establishments. Secchi was an indefatigable worker. In spite of many distracting duties which were forced on him by his official position Secchi managed to publish in the course of his life some seven hundred publications in many of the leading scien tific periodicals of his time in France, Britain, Germany as well as Italy. -
A Bibliometric Perspective Survey of Astronomical Object Tracking System
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Library Philosophy and Practice (e-journal) Libraries at University of Nebraska-Lincoln 2-15-2021 A Bibliometric Perspective Survey of Astronomical Object Tracking System Mariyam Ashai Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University), Pune, India, [email protected] Rhea Gautam Mukherjee Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University), Pune, India, [email protected] Sanjana Mundharikar Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University), Pune, India, [email protected] Vinayak Dev Kuanr Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University), Pune, India, [email protected] Shivali Amit Wagle Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University), Pune, India, [email protected] See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/libphilprac Part of the Library and Information Science Commons, and the Other Aerospace Engineering Commons Ashai, Mariyam; Mukherjee, Rhea Gautam; Mundharikar, Sanjana; Kuanr, Vinayak Dev; Wagle, Shivali Amit; and R, Harikrishnan, "A Bibliometric Perspective Survey of Astronomical Object Tracking System" (2021). Library Philosophy and Practice (e-journal). 5151. https://digitalcommons.unl.edu/libphilprac/5151 Authors Mariyam Ashai, Rhea Gautam Mukherjee, Sanjana Mundharikar, -
Arxiv:1703.10181V1 [Astro-Ph.SR] 29 Mar 2017 Ordo H G.W Alteesas“E Stragglers” “Red Stars These Call We Similar Found RGB
Draft version October 15, 2018 Preprint typeset using LATEX style emulateapj v. 01/23/15 ON THE ORIGIN OF SUB-SUBGIANT STARS II: BINARY MASS TRANSFER, ENVELOPE STRIPPING, AND MAGNETIC ACTIVITY Emily Leiner1, Robert D. Mathieu1, and Aaron M. Geller2,3 Draft version October 15, 2018 ABSTRACT Sub-subgiant stars (SSGs) lie to the red of the main-sequence and fainter than the red giant branch in cluster color-magnitude diagrams (CMDs), a region not easily populated by standard stellar evo- lution pathways. While there has been speculation on what mechanisms may create these unusual stars, no well-developed theory exists to explain their origins. Here we discuss three hypotheses of SSG formation: (1) mass transfer in a binary system, (2) stripping of a subgiant’s envelope, perhaps during a dynamical encounter, and (3) reduced luminosity due to magnetic fields that lower convective efficiency and produce large star spots. Using the stellar evolution code MESA, we develop evolu- tionary tracks for each of these hypotheses, and compare the expected stellar and orbital properties of these models with six known SSGs in the two open clusters M67 and NGC 6791. All three of these mechanisms can create stars or binary systems in the SSG CMD domain. We also calculate the frequency with which each of these mechanisms may create SSG systems, and find that the magnetic field hypothesis is expected to create SSGs with the highest frequency in open clusters. Mass transfer and envelope stripping have lower expected formation frequencies, but may nevertheless create occa- sional SSGs in open clusters. They may also be important mechanisms to create SSGs in higher mass globular clusters. -
Far-Infrared Observations of a Massive Cluster Forming in the Monoceros R2 filament Hub? T
Astronomy & Astrophysics manuscript no. monr2_hobys˙final˙corrected c ESO 2017 December 5, 2017 Far-infrared observations of a massive cluster forming in the Monoceros R2 filament hub? T. S. M. Rayner1??, M. J. Griffin1, N. Schneider2; 3, F. Motte4; 5, V. K¨onyves5, P. Andr´e5, J. Di Francesco6, P. Didelon5, K. Pattle7, D. Ward-Thompson7, L. D. Anderson8, M. Benedettini9, J.-P. Bernard10, S. Bontemps3, D. Elia9, A. Fuente11, M. Hennemann5, T. Hill5; 12, J. Kirk7, K. Marsh1, A. Men'shchikov5, Q. Nguyen Luong13; 14, N. Peretto1, S. Pezzuto9, A. Rivera-Ingraham15, A. Roy5, K. Rygl16, A.´ S´anchez-Monge2, L. Spinoglio9, J. Tig´e17, S. P. Trevi~no-Morales18, and G. J. White19; 20 1 Cardiff School of Physics and Astronomy, Cardiff University, Queen's Buildings, The Parade, Cardiff, Wales, CF24 3AA, UK 2 I. Physik. Institut, University of Cologne, 50937 Cologne, Germany 3 Laboratoire d'Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, all´eeG. Saint-Hilaire, 33615 Pessac, France 4 Universit´eGrenoble Alpes, CNRS, Institut de Planetologie et d'Astrophysique de Grenoble, 38000 Grenoble, France 5 Laboratoire AIM, CEA/IRFU { CNRS/INSU { Universit´eParis Diderot, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France 6 NRC, Herzberg Institute of Astrophysics, Victoria, Canada 7 Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK 8 Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506, USA 9 INAF { Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, I-00133 Roma, Italy 10 -
Data Delivery Document
The CygnusX Legacy Project Data Description: Delivery 1: July 2011 CygnusX team: Joseph L. Hora1 (PI), Sylvain Bontemps2, Tom Megeath3, Nicola Schneider4 , Frederique Motte4, Sean Carey5, Robert Simon6, Eric Keto1, Howard Smith1, Lori Allen7, Rob Gutermuth8, Giovanni Fazio1, Kathleen Kraemer9, Don Mizuno10, Stephan Price9, Joseph Adams11, Xavier Koenig12 1Harvard-Smithsonian Center for Astrophysics, 2Observatoire de Bordeaux, 3University of Toledo, 4CEA-Saclay, 5Spitzer Science Center, 6Universität zu Köln, 7NOAO, 8Smith College, 9Air Force Research Lab, 10Boston College, 11Cornell University, 12Goddard Space Flight Center Table of Contents 1. Project Summary ..................................................................................................................... 3 1.1 IRAC observations ........................................................................................................... 3 1.2 MIPS observations ........................................................................................................... 4 1.3 Data reduction .................................................................................................................. 5 1.3.1 IRAC reduction ......................................................................................................... 5 1.3.2 MIPS reduction ......................................................................................................... 7 2. Point Source Catalog.............................................................................................................. -
Discovery of a Wolf–Rayet Star Through Detection of Its Photometric Variability
The Astronomical Journal, 143:136 (6pp), 2012 June doi:10.1088/0004-6256/143/6/136 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. DISCOVERY OF A WOLF–RAYET STAR THROUGH DETECTION OF ITS PHOTOMETRIC VARIABILITY Colin Littlefield1, Peter Garnavich2, G. H. “Howie” Marion3,Jozsef´ Vinko´ 4,5, Colin McClelland2, Terrence Rettig2, and J. Craig Wheeler5 1 Law School, University of Notre Dame, Notre Dame, IN 46556, USA 2 Physics Department, University of Notre Dame, Notre Dame, IN 46556, USA 3 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 4 Department of Optics, University of Szeged, Hungary 5 Astronomy Department, University of Texas, Austin, TX 78712, USA Received 2011 November 9; accepted 2012 April 4; published 2012 May 2 ABSTRACT We report the serendipitous discovery of a heavily reddened Wolf–Rayet star that we name WR 142b. While photometrically monitoring a cataclysmic variable, we detected weak variability in a nearby field star. Low- resolution spectroscopy revealed a strong emission line at 7100 Å, suggesting an unusual object and prompting further study. A spectrum taken with the Hobby–Eberly Telescope confirms strong He ii emission and an N iv 7112 Å line consistent with a nitrogen-rich Wolf–Rayet star of spectral class WN6. Analysis of the He ii line strengths reveals no detectable hydrogen in WR 142b. A blue-sensitive spectrum obtained with the Large Binocular Telescope shows no evidence for a hot companion star. The continuum shape and emission line ratios imply a reddening of E(B − V ) = 2.2–2.6 mag. -
Calibration Against Spectral Types and VK Color Subm
Draft version July 19, 2021 Typeset using LATEX default style in AASTeX63 Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration Against Spectral Types and V-K Color Gerard T. van Belle,1 Kaspar von Braun,1 David R. Ciardi,2 Genady Pilyavsky,3 Ryan S. Buckingham,1 Andrew F. Boden,4 Catherine A. Clark,1, 5 Zachary Hartman,1, 6 Gerald van Belle,7 William Bucknew,1 and Gary Cole8, ∗ 1Lowell Observatory 1400 West Mars Hill Road Flagstaff, AZ 86001, USA 2California Institute of Technology, NASA Exoplanet Science Institute Mail Code 100-22 1200 East California Blvd. Pasadena, CA 91125, USA 3Systems & Technology Research 600 West Cummings Park Woburn, MA 01801, USA 4California Institute of Technology Mail Code 11-17 1200 East California Blvd. Pasadena, CA 91125, USA 5Northern Arizona University Department of Astronomy and Planetary Science NAU Box 6010 Flagstaff, Arizona 86011, USA 6Georgia State University Department of Physics and Astronomy P.O. Box 5060 Atlanta, GA 30302, USA 7University of Washington Department of Biostatistics Box 357232 Seattle, WA 98195-7232, USA 8Starphysics Observatory 14280 W. Windriver Lane Reno, NV 89511, USA (Received April 18, 2021; Revised June 23, 2021; Accepted July 15, 2021) Submitted to ApJ ABSTRACT We calculate directly determined values for effective temperature (TEFF) and radius (R) for 191 giant stars based upon high resolution angular size measurements from optical interferometry at the Palomar Testbed Interferometer. Narrow- to wide-band photometry data for the giants are used to establish bolometric fluxes and luminosities through spectral energy distribution fitting, which allow for homogeneously establishing an assessment of spectral type and dereddened V0 − K0 color; these two parameters are used as calibration indices for establishing trends in TEFF and R. -
White Dwarfs - Degenerate Stellar Configurations
White Dwarfs - Degenerate Stellar Configurations Austen Groener Department of Physics - Drexel University, Philadelphia, Pennsylvania 19104, USA Quantum Mechanics II May 17, 2010 Abstract The end product of low-medium mass stars is the degenerate stellar configuration called a white dwarf. Here we discuss the transition into this state thermodynamically as well as developing some intuition regarding the role of quantum mechanics in this process. I Introduction and Stellar Classification present at such high temperatures are small com- pared with the kinetic (thermal) energy of the parti- It is widely believed that the end stage of the low or cles. This assumption implies a mixture of free non- intermediate mass star is an extremely dense, highly interacting particles. One may also note that the pres- underluminous object called a white dwarf. Obser- sure of a mixture of different species of particles will vationally, these white dwarfs are abundant (∼ 6%) be the sum of the pressures exerted by each (this is in the Milky Way due to a large birthrate of their pro- where photon pressure (PRad) will come into play). genitor stars coupled with a very slow rate of cooling. Following this logic we can express the total stellar Roughly 97% of all stars will meet this fate. Given pressure as: no additional mass, the white dwarf will evolve into a cold black dwarf. PT ot = PGas + PRad = PIon + Pe− + PRad (1) In this paper I hope to introduce a qualitative de- scription of the transition from a main-sequence star At Hydrostatic Equilibrium: Pressure Gradient = (classification which aligns hydrogen fusing stars Gravitational Pressure.