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The Project Gutenberg Ebook #35588: <TITLE>
The Project Gutenberg EBook of Scientific Papers by Sir George Howard Darwin, by George Darwin This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org Title: Scientific Papers by Sir George Howard Darwin Volume V. Supplementary Volume Author: George Darwin Commentator: Francis Darwin E. W. Brown Editor: F. J. M. Stratton J. Jackson Release Date: March 16, 2011 [EBook #35588] Language: English Character set encoding: ISO-8859-1 *** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC PAPERS *** Produced by Andrew D. Hwang, Laura Wisewell, Chuck Greif and the Online Distributed Proofreading Team at http://www.pgdp.net (The original copy of this book was generously made available for scanning by the Department of Mathematics at the University of Glasgow.) transcriber's note The original copy of this book was generously made available for scanning by the Department of Mathematics at the University of Glasgow. Minor typographical corrections and presentational changes have been made without comment. This PDF file is optimized for screen viewing, but may easily be recompiled for printing. Please see the preamble of the LATEX source file for instructions. SCIENTIFIC PAPERS CAMBRIDGE UNIVERSITY PRESS C. F. CLAY, Manager Lon˘n: FETTER LANE, E.C. Edinburgh: 100 PRINCES STREET New York: G. P. PUTNAM'S SONS Bom`y, Calcutta and Madras: MACMILLAN AND CO., Ltd. Toronto: J. M. DENT AND SONS, Ltd. Tokyo: THE MARUZEN-KABUSHIKI-KAISHA All rights reserved SCIENTIFIC PAPERS BY SIR GEORGE HOWARD DARWIN K.C.B., F.R.S. -
Ice& Stone 2020
Ice & Stone 2020 WEEK 51: DECEMBER 13-19 Presented by The Earthrise Institute # 51 Authored by Alan Hale COMET OF THE WEEK: The Great Comet of 1680 Perihelion: 1680 December 18.49, q = 0.006 AU The Great Comet of 1680 over Rotterdam in The Netherlands, during late December 1680 as painted by the Dutch artist Lieve Verschuier. This particular comet was undoubtedly one of the brightest comets of the 17th Century, but it is also one of the most important comets in history from a scientific perspective, and perhaps even from the perspective of overall human history. While there were certainly plenty of superstitions attached to the comet’s appearance, the scientific investigations made of it were among the beginnings of the era in European history we now call The Enlightenment, and indeed, in a sense the Great Comet of 1680 can perhaps be considered as one of the sparks of that era. The significance began with the comet’s discovery, which was made on the morning of November 14, 1680, by a German astronomer residing in Coburg, Gottfried Kirch – the first comet ever to be discovered by means of a telescope. It was already around 4th magnitude at that time, and located near the star Regulus in the constellation Leo; from that point it traveled eastward and brightened rapidly, being closest to Earth (0.42 AU) on November 30. By that time it was a conspicuous naked-eye object with a tail 20 to 30 degrees long, and it remained visible for another week before disappearing into morning twilight. -
Moon-Earth-Sun: the Oldest Three-Body Problem
Moon-Earth-Sun: The oldest three-body problem Martin C. Gutzwiller IBM Research Center, Yorktown Heights, New York 10598 The daily motion of the Moon through the sky has many unusual features that a careful observer can discover without the help of instruments. The three different frequencies for the three degrees of freedom have been known very accurately for 3000 years, and the geometric explanation of the Greek astronomers was basically correct. Whereas Kepler’s laws are sufficient for describing the motion of the planets around the Sun, even the most obvious facts about the lunar motion cannot be understood without the gravitational attraction of both the Earth and the Sun. Newton discussed this problem at great length, and with mixed success; it was the only testing ground for his Universal Gravitation. This background for today’s many-body theory is discussed in some detail because all the guiding principles for our understanding can be traced to the earliest developments of astronomy. They are the oldest results of scientific inquiry, and they were the first ones to be confirmed by the great physicist-mathematicians of the 18th century. By a variety of methods, Laplace was able to claim complete agreement of celestial mechanics with the astronomical observations. Lagrange initiated a new trend wherein the mathematical problems of mechanics could all be solved by the same uniform process; canonical transformations eventually won the field. They were used for the first time on a large scale by Delaunay to find the ultimate solution of the lunar problem by perturbing the solution of the two-body Earth-Moon problem. -
Asteroid Family Identification 613
Bendjoya and Zappalà: Asteroid Family Identification 613 Asteroid Family Identification Ph. Bendjoya University of Nice V. Zappalà Astronomical Observatory of Torino Asteroid families have long been known to exist, although only recently has the availability of new reliable statistical techniques made it possible to identify a number of very “robust” groupings. These results have laid the foundation for modern physical studies of families, thought to be the direct result of energetic collisional events. A short summary of the current state of affairs in the field of family identification is given, including a list of the most reliable families currently known. Some likely future developments are also discussed. 1. INTRODUCTION calibrate new identification methods. According to the origi- nal papers published in the literature, Brouwer (1951) used The term “asteroid families” is historically linked to the a fairly subjective criterion to subdivide the Flora family name of the Japanese researcher Kiyotsugu Hirayama, who delineated by Hirayama. Arnold (1969) assumed that the was the first to use the concept of orbital proper elements to asteroids are dispersed in the proper-element space in a identify groupings of asteroids characterized by nearly iden- Poisson distribution. Lindblad and Southworth (1971) cali- tical orbits (Hirayama, 1918, 1928, 1933). In interpreting brated their method in such a way as to find good agree- these results, Hirayama made the hypothesis that such a ment with Brouwer’s results. Carusi and Massaro (1978) proximity could not be due to chance and proposed a com- adjusted their method in order to again find the classical mon origin for the members of these groupings. -
Analytical Model for the Tidal Evolution of the Evection 10.1029/2019JE006266 Resonance and the Timing of Resonance Escape Key Points: William R
RESEARCH ARTICLE Analytical Model for the Tidal Evolution of the Evection 10.1029/2019JE006266 Resonance and the Timing of Resonance Escape Key Points: William R. Ward1, Robin M. Canup1 , and Raluca Rufu1 • Capture of the Moon into the evection resonance with the Sun 1Planetary Science Directorate, Southwest Research Institute, Boulder, CO, USA transfers angular momentum from the Earth‐Moon to Earth's heliocentric orbit • Using the Mignard tidal model, we Abstract A high‐angular momentum giant impact with the Earth can produce a Moon with a silicate find that escape from evection isotopic composition nearly identical to that of Earth's mantle, consistent with observations of terrestrial occurs early with minimal angular and lunar rocks. However, such an event requires subsequent angular momentum removal for consistency momentum loss from the Earth‐Moon with the current Earth‐Moon system. The early Moon may have been captured into the evection resonance, • Processes beyond formal evection occurring when the lunar perigee precession period equals 1 year. It has been proposed that after a high‐ resonance are needed to reconcile a angular momentum giant impact, evection removed the angular momentum excess from the Earth‐Moon high‐angular momentum giant impact with the current Earth‐Moon pair and transferred it to Earth's orbit about the Sun. However, prior N‐body integrations suggest this result Supporting Information: depends on the tidal model and chosen tidal parameters. Here, we examine the Moon's encounter with • Supporting Information S1 evection using a complementary analytic description and the Mignard tidal model. While the Moon is in resonance, the lunar longitude of perigee librates, and if tidal evolution excites the libration amplitude Correspondence to: sufficiently, escape from resonance occurs. -
Arxiv:1603.07071V1
Dynamical Evidence for a Late Formation of Saturn’s Moons Matija Cuk´ Carl Sagan Center, SETI Institute, 189 North Bernardo Avenue, Mountain View, CA 94043 [email protected] Luke Dones Southwest Research Institute, Boulder, CO 80302 and David Nesvorn´y Southwest Research Institute, Boulder, CO 80302 Received ; accepted Revised and submitted to The Astrophysical Journal arXiv:1603.07071v1 [astro-ph.EP] 23 Mar 2016 –2– ABSTRACT We explore the past evolution of Saturn’s moons using direct numerical in- tegrations. We find that the past Tethys-Dione 3:2 orbital resonance predicted in standard models likely did not occur, implying that the system is less evolved than previously thought. On the other hand, the orbital inclinations of Tethys, Dione and Rhea suggest that the system did cross the Dione-Rhea 5:3 resonance, which is closely followed by a Tethys-Dione secular resonance. A clear implica- tion is that either the moons are significantly younger than the planet, or that their tidal evolution must be extremely slow (Q > 80, 000). As an extremely slow-evolving system is incompatible with intense tidal heating of Enceladus, we conclude that the moons interior to Titan are not primordial, and we present a plausible scenario for the system’s recent formation. We propose that the mid-sized moons re-accreted from a disk about 100 Myr ago, during which time Titan acquired its significant orbital eccentricity. We speculate that this disk has formed through orbital instability and massive collisions involving the previous generation of Saturn’s mid-sized moons. We identify the solar evection resonance perturbing a pair of mid-sized moons as the most likely trigger of such an insta- bility. -
1. INTRODUCTION Imations, We Thought It Worthwhile to Verify the Evolution the Origin of the Moon Is Still Unclear
THE ASTRONOMICAL JOURNAL, 115:1653È1663, 1998 April ( 1998. The American Astronomical Society. All rights reserved. Printed in the U.S.A. RESONANCES IN THE EARLY EVOLUTION OF THE EARTH-MOON SYSTEM JIHAD TOUMA McDonald Observatory, University of Texas, Austin, TX 78712; touma=harlan.as.utexas.edu AND JACK WISDOM Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139; wisdom=mit.edu Received 1997 November 25; revised 1997 December 26 ABSTRACT Most scenarios for the formation of the Moon place the Moon near Earth in low-eccentricity orbit in the equatorial plane of Earth. We examine the dynamical evolution of the Earth-Moon system from such initial conÐgurations. We Ðnd that during the early evolution of the system, strong orbital resonances are encountered. Passage through these resonances can excite large lunar orbital eccentricity and modify the inclination of the Moon to the equator. Scenarios that resolve the mutual inclination problem are presented. A period of large lunar eccentricity would result in substantial tidal heating in the early Moon, providing a heat source for the lunar magma ocean. The resonance may also play a role in the formation of the Moon. Key words: celestial mechanics, stellar dynamics È Earth È Moon regression of the MoonÏs node. With so many approx- 1. INTRODUCTION imations, we thought it worthwhile to verify the evolution The origin of the Moon is still unclear. The classic sce- of the system with numerical simulation. Our hope was that narios for the formation of the Moon include coaccretion, through direct numerical simulation we would uncover Ðssion, and capture. -
A Modern Almagest an Updated Version of Ptolemy’S Model of the Solar System
A Modern Almagest An Updated Version of Ptolemy’s Model of the Solar System Richard Fitzpatrick Professor of Physics The University of Texas at Austin Contents 1 Introduction 5 1.1 Euclid’sElementsandPtolemy’sAlmagest . ......... 5 1.2 Ptolemy’sModeloftheSolarSystem . ..... 5 1.3 Copernicus’sModeloftheSolarSystem . ....... 10 1.4 Kepler’sModeloftheSolarSystem . ..... 11 1.5 PurposeofTreatise .................................. .. 12 2 Spherical Astronomy 15 2.1 CelestialSphere................................... ... 15 2.2 CelestialMotions ................................. .... 15 2.3 CelestialCoordinates .............................. ..... 15 2.4 EclipticCircle .................................... ... 17 2.5 EclipticCoordinates............................... ..... 18 2.6 SignsoftheZodiac ................................. ... 19 2.7 Ecliptic Declinations and Right Ascenesions. ........... 20 2.8 LocalHorizonandMeridian ............................ ... 20 2.9 HorizontalCoordinates.............................. .... 23 2.10 MeridianTransits .................................. ... 24 2.11 Principal Terrestrial Latitude Circles . ......... 25 2.12 EquinoxesandSolstices. ....... 25 2.13 TerrestrialClimes .................................. ... 26 2.14 EclipticAscensions .............................. ...... 27 2.15 AzimuthofEclipticAscensionPoint . .......... 29 2.16 EclipticAltitudeandOrientation. .......... 30 3 Dates 63 3.1 Introduction...................................... .. 63 3.2 Determination of Julian Day Numbers . .... 63 4 Geometric -
Coupled Orbital-Thermal Evolution of the Early Earth-Moon System with a Fast-Spinning Earth
Icarus 281 (2017) 90–102 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Coupled orbital-thermal evolution of the early Earth-Moon system with a fast-spinning Earth ∗ ZhenLiang Tian a, , Jack Wisdom a, Linda Elkins-Tanton b a Massachusetts Institute of Technology, Cambridge, MA 02139, USA b School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281, USA a r t i c l e i n f o a b s t r a c t Article history: Several new scenarios of the Moon-forming giant impact have been proposed to reconcile the giant im- Available online 6 September 2016 pact theory with the recent recognition of the volatile and refractory isotopic similarities between Moon and Earth. Two scenarios leave the post-impact Earth spinning much faster than what is inferred from Keywords: Moon the present Earth-Moon system’s angular momentum. The evection resonance has been proposed to drain Planetary dynamics the excess angular momentum, but the lunar orbit stays at high orbital eccentricities for long periods in Thermal histories the resonance, which would cause large tidal heating in the Moon. A limit cycle related to the evec- Solid body tides tion resonance has also been suggested as an alternative mechanism to reduce the angular momentum, which keeps the lunar orbit at much lower eccentricities, and operates in a wider range of parameters. In this study we use a coupled thermal-orbital model to determine the effect of the change of the Moon’s thermal state on the Earth-Moon system’s dynamical history. -
Tidal Evolution of the Evection Resonance/Quasi-Resonance and the Angular Momentum of the Earth-Moon System
Accepted manuscript JGR-Planets Tidal Evolution of the Evection Resonance/Quasi-Resonance and the Angular Momentum of the Earth-Moon System R. Rufu and R. M. Canup Planetary Science Directorate, Southwest Research Institute, Boulder, Colorado, 80302, USA Key Points: • Evection resonance and a subsequent quasi-resonance regime may remove an- gular momentum from the Earth-Moon system. • Only a narrow range of fixed tidal parameters can reconcile a high-angular momentum Moon-forming impact with the current Earth-Moon system. • For a time-dependent terrestrial dissipation model, quasi-resonance escape oc- curs early, leaving the system with an angular momentum excess. Corresponding author: R. Rufu, [email protected] {1{ Accepted manuscript JGR-Planets Abstract Forming the Moon by a high-angular momentum impact may explain the Earth- Moon isotopic similarities, however, the post-impact angular momentum needs to be reduced by a factor of 2 or more to the current value (1 LEM) after the Moon forms. Capture into the evection resonance, occurring when the lunar perigee precession pe- riod equals one year, could remove the angular momentum excess. However the ap- propriate angular momentum removal appears sensitive to the tidal model and chosen tidal parameters. In this work, we use a constant-time delay tidal model to explore the Moon's orbital evolution through evection. We find that exit from formal evec- tion occurs early and that subsequently, the Moon enters a quasi-resonance regime, in which evection still regulates the lunar eccentricity even though the resonance an- gle is no longer librating. Although not in resonance proper, during quasi-resonance angular momentum is continuously removed from the Earth-Moon system and trans- ferred to Earth's heliocentric orbit. -
Taxonomic Classification of Asteroids Based on MOVIS Near-Infrared Colors
A&A 617, A12 (2018) https://doi.org/10.1051/0004-6361/201833023 Astronomy & © ESO 2018 Astrophysics Taxonomic classification of asteroids based on MOVIS near-infrared colors? M. Popescu1,2,3, J. Licandro1,2, J. M. Carvano4, R. Stoicescu3, J. de León1,2, D. Morate1,2, I. L. Boaca˘3, and C. P. Cristescu5 1 Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain 2 Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain e-mail: [email protected] 3 Astronomical Institute of the Romanian Academy, 5 Cu¸titulde Argint, 040557 Bucharest, Romania 4 Observatório Nacional, rua Gal. José Cristino 77, São Cristóvão, 20921-400 Rio de Janeiro, Brazil 5 Department of Physics, University Politehnica of Bucharest, Bucure¸sti 060042, Romania Received 14 March 2018 / Accepted 14 June 2018 ABSTRACT Context. The MOVIS catalog contains the largest set of near-infrared (NIR) colors for solar system objects. These data were obtained from the observations performed by VISTA-VHS survey using the Y, J, H, and Ks filters. The taxonomic classification of objects in this catalog allows us to obtain large-scale distributions for the asteroidal population, to study faint objects, and to select targets for detailed spectral investigations. Aims. We aim to provide a taxonomic classification for asteroids observed by VISTA-VHS survey. We derive a method for assigning a compositional type to an object based on its (Y − J), (J − Ks), and (H − Ks) colors. Methods. We present a taxonomic classification for 18 265 asteroids from the MOVIS catalog, using a probabilistic method and the k-nearest neighbors algorithm. -
Detection of the Yarkovsky Effect for Main-Belt Asteroids
Icarus 170 (2004) 324–342 www.elsevier.com/locate/icarus Detection of the Yarkovsky effect for main-belt asteroids David Nesvorný ∗, William F. Bottke Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302, USA Received 19 February 2004; revised 1 April 2004 Available online 9 June 2004 Abstract The Yarkovsky effect, a non-gravitational acceleration produced by the anisotropic emission of thermal energy (Öpik, 1951, Proc. Roy. Irish Acad. 54, 165–199), plays an important role in the dynamical evolution of asteroids. Current theoretical models of the Yarkovsky effect, however, rely on a number of poorly known parameters that can only approximate how real asteroids respond to solar heating. To improve this situation, we investigated whether the orbital distribution of the Karin cluster, a 5.8 ± 0.2 Myr old S-type asteroid family (Nesvorný et al., 2002a, Nature 417, 720–722), could be used to determine the rate at which multikilometer main-belt asteroids spread in semimajor axis due to the Yarkovsky effect. Our results indicate that the orbital histories of individual Karin cluster members bear clear signatures of having drifted in semimajor axis drift since their formation. Using numerical methods, we determined the drift speed of ≈ 70 Karin cluster members (asteroids 1–6 km in diameter). This is the first time the speed that main-belt asteroids evolve in the semimajor axis due to the non-gravitational effects have been measured. The magnitude of measured speeds is similar to those predicted by theoretical models of the Yarkovsky force. Taken together, our results represent the first direct detection of the Yarkovsky effect for main-belt asteroids, and they validate in significant ways the asteroid thermal models described in the recent literature (e.g., Vokrouhlický, 1999, Astron.