The Solar System and Its Place in the Galaxy in Encyclopedia of the Solar System by Paul R
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Stellar Dynamics and Stellar Phenomena Near a Massive Black Hole
Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole Tal Alexander Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl St, Rehovot, Israel 76100; email: [email protected] | Author's original version. To appear in Annual Review of Astronomy and Astrophysics. See final published version in ARA&A website: www.annualreviews.org/doi/10.1146/annurev-astro-091916-055306 Annu. Rev. Astron. Astrophys. 2017. Keywords 55:1{41 massive black holes, stellar kinematics, stellar dynamics, Galactic This article's doi: Center 10.1146/((please add article doi)) Copyright c 2017 by Annual Reviews. Abstract All rights reserved Most galactic nuclei harbor a massive black hole (MBH), whose birth and evolution are closely linked to those of its host galaxy. The unique conditions near the MBH: high velocity and density in the steep po- tential of a massive singular relativistic object, lead to unusual modes of stellar birth, evolution, dynamics and death. A complex network of dynamical mechanisms, operating on multiple timescales, deflect stars arXiv:1701.04762v1 [astro-ph.GA] 17 Jan 2017 to orbits that intercept the MBH. Such close encounters lead to ener- getic interactions with observable signatures and consequences for the evolution of the MBH and its stellar environment. Galactic nuclei are astrophysical laboratories that test and challenge our understanding of MBH formation, strong gravity, stellar dynamics, and stellar physics. I review from a theoretical perspective the wide range of stellar phe- nomena that occur near MBHs, focusing on the role of stellar dynamics near an isolated MBH in a relaxed stellar cusp. -
Astr-Astronomy 1
ASTR-ASTRONOMY 1 ASTR 1116. Introduction to Astronomy Lab, Special ASTR-ASTRONOMY 1 Credit (1) This lab-only listing exists only for students who may have transferred to ASTR 1115G. Introduction Astro (lec+lab) NMSU having taken a lecture-only introductory astronomy class, to allow 4 Credits (3+2P) them to complete the lab requirement to fulfill the general education This course surveys observations, theories, and methods of modern requirement. Consent of Instructor required. , at some other institution). astronomy. The course is predominantly for non-science majors, aiming Restricted to Las Cruces campus only. to provide a conceptual understanding of the universe and the basic Prerequisite(s): Must have passed Introduction to Astronomy lecture- physics that governs it. Due to the broad coverage of this course, the only. specific topics and concepts treated may vary. Commonly presented Learning Outcomes subjects include the general movements of the sky and history of 1. Course is used to complete lab portion only of ASTR 1115G or ASTR astronomy, followed by an introduction to basic physics concepts like 112 Newton’s and Kepler’s laws of motion. The course may also provide 2. Learning outcomes are the same as those for the lab portion of the modern details and facts about celestial bodies in our solar system, as respective course. well as differentiation between them – Terrestrial and Jovian planets, exoplanets, the practical meaning of “dwarf planets”, asteroids, comets, ASTR 1120G. The Planets and Kuiper Belt and Trans-Neptunian Objects. Beyond this we may study 4 Credits (3+2P) stars and galaxies, star clusters, nebulae, black holes, and clusters of Comparative study of the planets, moons, comets, and asteroids which galaxies. -
Systematic Motions in the Galactic Plane Found in the Hipparcos
Astronomy & Astrophysics manuscript no. cabad0609 September 30, 2018 (DOI: will be inserted by hand later) Systematic motions in the galactic plane found in the Hipparcos Catalogue using Herschel’s Method Carlos Abad1,2 & Katherine Vieira1,3 (1) Centro de Investigaciones de Astronom´ıa CIDA, 5101-A M´erida, Venezuela e-mail: [email protected] (2) Grupo de Mec´anica Espacial, Depto. de F´ısica Te´orica, Universidad de Zaragoza. 50006 Zaragoza, Espa˜na (3) Department of Astronomy, Yale University, P.O. Box 208101 New Haven, CT 06520-8101, USA e-mail: [email protected] September 30, 2018 Abstract. Two motions in the galactic plane have been detected and characterized, based on the determination of a common systematic component in Hipparcos catalogue proper motions. The procedure is based only on positions, proper motions and parallaxes, plus a special algorithm which is able to reveal systematic trends. Our results come o o o o from two stellar samples. Sample 1 has 4566 stars and defines a motion of apex (l,b) = (177 8, 3 7) ± (1 5, 1 0) and space velocity V = 27 ± 1 km/s. Sample 2 has 4083 stars and defines a motion of apex (l,b)=(5o4, −0o6) ± o o (1 9, 1 1) and space velocity V = 32 ± 2 km/s. Both groups are distributed all over the sky and cover a large variety of spectral types, which means that they do not belong to a specific stellar population. Herschel’s method is used to define the initial samples of stars and later to compute the common space velocity. -
ASTRON 449: Stellar Dynamics Winter 2017 in This Course, We Will Cover
ASTRON 449: Stellar Dynamics Winter 2017 In this course, we will cover • the basic phenomenology of galaxies (including dark matter halos, stars clusters, nuclear black holes) • theoretical tools for research on galaxies: potential theory, orbit integration, statistical description of stellar systems, stability of stellar systems, disk dynamics, interactions of stellar systems • numerical methods for N-body simulations • time permitting: kinetic theory, basics of galaxy formation Galaxy phenomenology Reading: BT2, chap. 1 intro and section 1.1 What is a galaxy? The Milky Way disk of stars, dust, and gas ~1011 stars 8 kpc 1 pc≈3 lyr Sun 6 4×10 Msun black hole Gravity turns gas into stars (all in a halo of dark matter) Galaxies are the building blocks of the Universe Hubble Space Telescope Ultra-Deep Field Luminosity and mass functions MW is L* galaxy Optical dwarfs Near UV Schechter fits: M = 2.5 log L + const. − 10 Local galaxies from SDSS; Blanton & Moustakas 08 Hubble’s morphological classes bulge or spheroidal component “late type" “early type" barred http://skyserver.sdss.org/dr1/en/proj/advanced/galaxies/tuningfork.asp Not a time or physical sequence Galaxy rotation curves: evidence for dark matter M33 rotation curve from http://en.wikipedia.org/wiki/Galaxy_rotation_curve Galaxy clusters lensing arcs Abell 1689 ‣ most massive gravitational bound objects in the Universe ‣ contain up to thousands of galaxies ‣ most baryons intracluster gas, T~107-108 K gas ‣ smaller collections of bound galaxies are called 'groups' Bullet cluster: more -
Numerical Computations in Stellar Dynamics
Particle Accelerators, 1986, Vol. 19, pp. 37-42 0031-2460/86/1904-0037/$15.00/0 © 1986 Gordon and Breach, Science Publishers, S.A. Printed in the United States of America NUMERICAL COMPUTATIONS IN STELLAR DYNAMICS PIET HUTt Department ofAstronomy, University of California, Berkeley, CA 94720 An outline is given of the main similarities and differences between gravitational dynamics and the other fields of interest at the present conference: accelerator orbital dynamics and plasma physics. Gravitational dynamics can be divided into two rather distinct fields, celestial mechanics and stellar dynamics. The field of stellar dynamics is concerned with astrophysical applications of the general gravitational N -body problem, which addresses the question: for a system of N point masses with given initial conditions, describe its evolution under Newtonian gravity. Major subfields within stellar dynamics are listed and classified according to the collisional or collisionless character of different problems. A number of review papers are mentioned and briefly discussed, to provide a few starting points for exploring the vast recent literature on stellar dynamics. I. INTRODUCTION Gravitational dynamics naturally divides into two rather distinct fields, celestial mechanics and stellar dynamics. The former is concerned with the long-term evolution of well-behaved, small, and ordered systems such as the motion of the planets around the sun, and that of natural and artificial satellites around the sun and planets. The latter covers the behavior of much larger systems consisting of many particles, each of which move on random paths constrained only by a globally averaged distribution, just as atoms move in a gas. -
The Milky Way
Unit 4: The Milky Way This material was developed by the Friends of the Dominion Astrophysical Observatory with the assistance of a Natural Science and Engineering Research Council PromoScience grant and the NRC. It is a part of a larger project to present grade-appropriate material that matches 2020 curriculum requirements to help students understand planets, with a focus on exoplanets. This material is aimed at BC Grade 6 students. French versions are available. Instructions for teachers ● For questions and to give feedback contact: Calvin Schmidt [email protected], ● All units build towards the Big Idea in the curriculum showing our solar system in the context of the Milky Way and the Universe, and provide background for understanding exoplanets. ● Look for Ideas for extending this section, Resources, and Review and discussion questions at the end of each topic in this Unit. These should give more background on each subject and spark further classroom ideas. We would be happy to help you expand on each topic and develop your own ideas for your students. Contact us at the [email protected]. Instructions for students ● If there are parts of this unit that you find confusing, please contact us at [email protected] for help. ● We recommend you do a few sections at a time. We have provided links to learn more about each topic. ● You don’t have to do the sections in order, but we recommend that. Do sections you find interesting first and come back and do more at another time. ● It is helpful to try the activities rather than just read them. -
Index to JRASC Volumes 61-90 (PDF)
THE ROYAL ASTRONOMICAL SOCIETY OF CANADA GENERAL INDEX to the JOURNAL 1967–1996 Volumes 61 to 90 inclusive (including the NATIONAL NEWSLETTER, NATIONAL NEWSLETTER/BULLETIN, and BULLETIN) Compiled by Beverly Miskolczi and David Turner* * Editor of the Journal 1994–2000 Layout and Production by David Lane Published by and Copyright 2002 by The Royal Astronomical Society of Canada 136 Dupont Street Toronto, Ontario, M5R 1V2 Canada www.rasc.ca — [email protected] Table of Contents Preface ....................................................................................2 Volume Number Reference ...................................................3 Subject Index Reference ........................................................4 Subject Index ..........................................................................7 Author Index ..................................................................... 121 Abstracts of Papers Presented at Annual Meetings of the National Committee for Canada of the I.A.U. (1967–1970) and Canadian Astronomical Society (1971–1996) .......................................................................168 Abstracts of Papers Presented at the Annual General Assembly of the Royal Astronomical Society of Canada (1969–1996) ...........................................................207 JRASC Index (1967-1996) Page 1 PREFACE The last cumulative Index to the Journal, published in 1971, was compiled by Ruth J. Northcott and assembled for publication by Helen Sawyer Hogg. It included all articles published in the Journal during the interval 1932–1966, Volumes 26–60. In the intervening years the Journal has undergone a variety of changes. In 1970 the National Newsletter was published along with the Journal, being bound with the regular pages of the Journal. In 1978 the National Newsletter was physically separated but still included with the Journal, and in 1989 it became simply the Newsletter/Bulletin and in 1991 the Bulletin. That continued until the eventual merger of the two publications into the new Journal in 1997. -
Beckett Rosenfeld Hercules O
272 Feature Star Field STARS 273 HERCULES BY CHRIS BECKETT & RANDALL ROSENFELD Right there in its orbit wheels a Phantom form, like to a man that strives at a task. That sign no man knows how to read clearly, nor on what task he is bent, but men simply call him On His Knees [Engonasin]. Now that Phantom, that toils on his knees, seems to sit on bended knee, and from both his shoulders his hands are upraised and stretch, one this way, one that, a fathom’s length. Over the middle of the head of the crooked Dragon, he has the tip of his right foot; Aratus (fl. ca. 390–240 BC), Phaenomena, Mair trs. 1921, 384–387. The keystone star pattern of Hercules keeps the celestial sphere of summer suspended overhead for northern observers and just fits in a º9 binocular. The Romans associated the “Kneeling One” to the mythical strongman Hercules, now known as home to one of the first deep-sky objects observers learn to locate by heart, Messier 13. However, there is much more worth taking a gaze at as the constellation passes through zenith. Rasalgethi represents the “head of the kneeler” and means northern observers imagine Hercules upside down. William Herschel discovered the variability of Rasalgethi changes from an eye-catching 2.7 magnitude to a 4.0 over a six-year period, greatly altering the region of the sky. Small telescopes split it into two components, a brilliant red-orange pri- mary and rare blue-green secondary. For those more interested in star patterns than variables, DoDz 7’s sailboat-shaped pattern of stars is a low-power telescope field to the north. -
Crucifying the Earth on the Galactic Cross 1
Crucifying the Earth on the Galactic Cross 1 CRUCIFYING THE EARTH ON THE GALACTIC CROSS Sergey Smelyakov, Jan Wicherink The Cross of Hendaye presenting the Astronomical and Eight-pointed Crosses (See Supplements 1, 2) 1. INTRODUCTION While the world is anticipating the effects of the End of the Maya Long Count Calendar on December 21 2012, they have already started to develop right in front of our eyes. The Cross, in all its forms, presents the most ancient symbol, and a series of meanings stands behind each of them (See Supplement 1). Some of these meanings are not widely known until our days; some other ones are still veiling the ancient esoteric concepts. The meaning of the majority of these corresponds to astronomical facts and evolution of the Earth and mankind that was kept secret for millennia . But from the 19th century a significant part of these symbols was explained – partly due to the disclosing of the Ancient Knowledge in works of Helen Blavatsky, – partly due to the progress of the sciences. For this reason we may suggest that this disclosure, by itself, presents great importance defining the last two centuries as the age of great revelations; if so, we may expect that they are given purposefully, in order to prepare us for something important. And we actually see this from a series of independent studies that the current decades can be characterised as the outstanding ones over the millennia; a series of seldom Space phenomena and the End of the Mayan calendar are evidently between them. In 1996, the concept of the Solar System Zodiac (SZ) was developed as a natural affiliate to the Tropical Zodiac (TZ). -
Label Year Title Authors Status BD511 1970 1970 Great Ideas And
Label Year Title Authors Status BD511 1970 1970 Great ideas and theories of modern cosmology Singh, Jagjit present HX308 1982 1982 Herinneringen: herinneringen uit de arbeidersbeweging: sterrenku Pannekoek, Anton present OB466 2014A 2014 Accretion Processes in Astrophysics: Canary Islands Winter School in As Gonzalez Martinez-Pais, I., Shabaz T., and present Q11 1990 1990 Galactic models Buchler, J.Robert present Q11 1992 1992 Astrophysical disks Dermott, S.F. present Q11 1997 1997 Near-earth objects: the United Nations International Conference Remo, John L. present Q11 1998 1998 Nonlinear dynamics and chaos in astrophysics: a festschrift in h Buchler, J.R. present Q125 1950 1950 De mechanisering van het wereldbeeld Dijksterhuis, E.J. present Q171 1932 1932 The mysterious universe Jeans, James present Q183 2013 A 2013 Data-driven modelling and scientific computation: methods for complex Kutz J.N. present Q56 1976 1976 Astrophysique et spectroscopie: communications pres. au colloque present QA1 1976 1976 Supersonic flow and shock waves Courant, R. present QA273 1964 A 1964 Inleiding tot de waarschijnlijkheidsrekening Stam, A.J. present QA273 1964 B 1964 Method of statistical testing Shreider, Yu.A. present QA276 2013 A 2013 Scientific Inference Vaughan, Simon present QA280 1997 1997 Applications of time series analysis in astronomy and meteorolog Subba Rao, T. present QA280 2004 A 2004 The analysis of time series: an introduction Chatfield, Chris present QA297 2003 2003 Smoothed particle hydrodynamics: a meshfree particle method Liu, G.R. present QA297 2007 A 2007 Numerical recipes: the art of scientific computing 3rd ed. Press W.H., Teukolsky S.A., Vetterling W.T present QA3 1960 1960 Figures of equilibrium of celestial bodies: with emphasis on pro Kopal, Zdenek present QA300 1956 1956 Introduction to numerical analysis Hildebrand, F.B. -
Stellar Dynamics E NCYCLOPEDIA of a STRONOMY and a STROPHYSICS
Stellar Dynamics E NCYCLOPEDIA OF A STRONOMY AND A STROPHYSICS Stellar Dynamics Stellar dynamics describes systems of many point mass particles whose mutual gravitational interactions determine their orbits. These particles are usually taken to represent stars in small GALAXY CLUSTERS with 2 3 about 10 –10 members, or in larger GLOBULAR CLUSTERS 4 6 with 10 –10 members or in GALACTIC NUCLEI with up to about 109 members or in galaxies containing as many as 1012 stars. Under certain conditions, stellar dynamics can also describe the motions of galaxies in clusters, and even the general clustering of galaxies throughout the universe Figure 1. The deflection of a star m2 by a more massive star m1, itself. This last case is known as the cosmological many- schematically illustrating two-body relaxation. body problem. The essential physical feature of all these examples is that each particle (whether it represents a star or random orbits, their mean free path to geometric collisions an entire galaxy) contributes importantly to the overall is R3 gravitational field. In this way, the subject differs from λG ≈ 1/nσ ≈ d (1) Nd3 CELESTIAL MECHANICS where the gravitational force of a 3 massive planet or star dominates its satellite orbits. Stellar where R is the radius of a spherical system containing N dynamical orbits are generally much more irregular and objects distributed approximately uniformly. chaotic than those of celestial mechanical systems. This has two easy physical interpretations. First, the Consequently, the description of stellar dynamical average number of times an object can move through its systems is usually concerned with the statistical properties own diameter before colliding is essentially the ratio of the of many orbits rather than with the detailed positions and cluster’s volume to that occupied by all the stars. -
OBSERVATION of LYMAN-~T EMISSION in INTERPLANETARY SPACE J
OBSERVATION OF LYMAN-~t EMISSION IN INTERPLANETARY SPACE J. L. Bertaux and J. E. Blamont The extraterrestrial Lyman-a emission was mapped by the OGO 5 satellite, when it was ABSTRACT outside the geocorona. Three maps, obtained at different periods of the year, are presented and analyzed. The results suggest that at least half of the emission takes place in the solar system, and give strong support to the theory that in its motion towards the apex, the sun crosses neutral atomic hydrogen of interstellar origin, giving rise to an apparent interstellar wind. INTRODUCTION DESCRIPTION OF THE DATA The extraterrestrial Lyman-a emission could be provided At our request, OGO 5 was temporarily placed in a spe- by the free atoms of hydrogen in interstellar space, cial spinning mode on three occasions: 12- 14 Septem- which are excited by light emission of the stars at the ber 1969, 15-17 December 1969, and 1-3 April 1970. wavelength of Lyman-a. Then it is expected that they These spinup operations, referred to as SU 1, SU 2, and would absorb and re-emit Lyman-a photons. This emis- SU 3, respectively, took place when OGO 5 was well sion could have two possible angular distributions: outside the geocorona (above 90,000 km altitude). 1. The emission could come directly from the distant Two different experiments on board OGO 5 were parts of the galaxy. Because of Doppler shifting, the able to map the Lymana background from these maneu- emission would not be completely absorbed by the vers. One was the two-channel photometer of C.