Computational Physics Project 3 Comet Dust Tails
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1 Characterization of Cometary Activity of 67P/Churyumov-Gerasimenko
Characterization of cometary activity of 67P/Churyumov-Gerasimenko comet Abstract After 2.5 years from the end of the mission, the data provided by the ESA/Rosetta mission still leads to important results about 67P/Churyumov-Gerasimenko (hereafter 67P), belonging to the Jupiter Family Comets. Since comets are among the most primitive bodies of the Solar System, the understanding of their formation and evolution gives important clues about the early stages of our planetary system, including the scenarios of water delivery to Earth. At the present state of knowledge, 67P’s activity has been characterized by measuring the physical properties of the gas and dust coma, by detecting water ice patches on the nucleus surface and by analyzing some peculiar events, such as outbursts. We propose an ISSI International Team to build a more complete scenario of the 67P activity during different stages of its orbit. The retrieved results in terms of dust emission, morphology and composition will be linked together in order to offer new insights about 67P formation and evolution. In particular the main goals of the project are: 1. Retrieval of the activity degree of different 67P geomorphological nucleus regions in different time periods, by reconstructing the motion of the dust particles revealed in the coma; 2. Identification of the main drivers of cometary activity, by studying the link between cometary activity and illumination/local time, dust morphology, surface geomorphology, dust composition. The project will shed light on how (and if) cometary activity is related to surface geology and/or composition or is just driven by local illumination. -
Stardust Comet Flyby
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Stardust Comet Flyby Press Kit January 2004 Contacts Don Savage Policy/Program Management 202/358-1727 NASA Headquarters, Washington DC Agle Stardust Mission 818/393-9011 Jet Propulsion Laboratory, Pasadena, Calif. Vince Stricherz Science Investigation 206/543-2580 University of Washington, Seattle, WA Contents General Release ……………………………………......………….......................…...…… 3 Media Services Information ……………………….................…………….................……. 5 Quick Facts …………………………………………..................………....…........…....….. 6 Why Stardust?..................…………………………..................………….....………......... 7 Other Comet Missions ....................................................................................... 10 NASA's Discovery Program ............................................................................... 12 Mission Overview …………………………………….................……….....……........…… 15 Spacecraft ………………………………………………..................…..……........……… 25 Science Objectives …………………………………..................……………...…........….. 34 Program/Project Management …………………………...................…..…..………...... 37 1 2 GENERAL RELEASE: NASA COMET HUNTER CLOSING ON QUARRY Having trekked 3.2 billion kilometers (2 billion miles) across cold, radiation-charged and interstellar-dust-swept space in just under five years, NASA's Stardust spacecraft is closing in on the main target of its mission -- a comet flyby. "As the saying goes, 'We are good to go,'" said project manager Tom Duxbury at NASA's Jet -
Radiation Forces on Small Particles in the Solar System T
1CARUS 40, 1-48 (1979) Radiation Forces on Small Particles in the Solar System t JOSEPH A. BURNS Cornell University, 2 Ithaca, New York 14853 and NASA-Ames Research Center PHILIPPE L. LAMY CNRS-LAS, Marseille, France 13012 AND STEVEN SOTER Cornell University, Ithaca, New York 14853 Received May 12, 1978; revised May 2, 1979 We present a new and more accurate expression for the radiation pressure and Poynting- Robertson drag forces; it is more complete than previous ones, which considered only perfectly absorbing particles or artificial scattering laws. Using a simple heuristic derivation, the equation of motion for a particle of mass m and geometrical cross section A, moving with velocity v through a radiation field of energy flux density S, is found to be (to terms of order v/c) mi, = (SA/c)Qpr[(1 - i'/c)S - v/c], where S is a unit vector in the direction of the incident radiation,/" is the particle's radial velocity, and c is the speed of light; the radiation pressure efficiency factor Qpr ~ Qabs + Q~a(l - (cos a)), where Qabs and Q~c~ are the efficiency factors for absorption and scattering, and (cos a) accounts for the asymmetry of the scattered radiation. This result is confirmed by a new formal derivation applying special relativistic transformations for the incoming and outgoing energy and momentum as seen in the particle and solar frames of reference. Qpr is evaluated from Mie theory for small spherical particles with measured optical properties, irradiated by the actual solar spectrum. Of the eight materials studied, only for iron, magnetite, and graphite grains does the radiation pressure force exceed gravity and then just for sizes around 0. -
Section 22-3: Energy, Momentum and Radiation Pressure
Answer to Essential Question 22.2: (a) To find the wavelength, we can combine the equation with the fact that the speed of light in air is 3.00 " 108 m/s. Thus, a frequency of 1 " 1018 Hz corresponds to a wavelength of 3 " 10-10 m, while a frequency of 90.9 MHz corresponds to a wavelength of 3.30 m. (b) Using Equation 22.2, with c = 3.00 " 108 m/s, gives an amplitude of . 22-3 Energy, Momentum and Radiation Pressure All waves carry energy, and electromagnetic waves are no exception. We often characterize the energy carried by a wave in terms of its intensity, which is the power per unit area. At a particular point in space that the wave is moving past, the intensity varies as the electric and magnetic fields at the point oscillate. It is generally most useful to focus on the average intensity, which is given by: . (Eq. 22.3: The average intensity in an EM wave) Note that Equations 22.2 and 22.3 can be combined, so the average intensity can be calculated using only the amplitude of the electric field or only the amplitude of the magnetic field. Momentum and radiation pressure As we will discuss later in the book, there is no mass associated with light, or with any EM wave. Despite this, an electromagnetic wave carries momentum. The momentum of an EM wave is the energy carried by the wave divided by the speed of light. If an EM wave is absorbed by an object, or it reflects from an object, the wave will transfer momentum to the object. -
Dust-To-Gas and Refractory-To-Ice Mass Ratios of Comet 67P
Dust-to-Gas and Refractory-to-Ice Mass Ratios of Comet 67P/Churyumov-Gerasimenko from Rosetta Observations Mathieu Choukroun, Kathrin Altwegg, Ekkehard Kührt, Nicolas Biver, Dominique Bockelée-Morvan, Joanna Drążkowska, Alain Hérique, Martin Hilchenbach, Raphael Marschall, Martin Pätzold, et al. To cite this version: Mathieu Choukroun, Kathrin Altwegg, Ekkehard Kührt, Nicolas Biver, Dominique Bockelée-Morvan, et al.. Dust-to-Gas and Refractory-to-Ice Mass Ratios of Comet 67P/Churyumov-Gerasimenko from Rosetta Observations. Journal Space Science Reviews, 2020, 10.1007/s11214-020-00662-1. hal- 03021621 HAL Id: hal-03021621 https://hal.archives-ouvertes.fr/hal-03021621 Submitted on 29 Aug 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution| 4.0 International License Space Sci Rev (2020) 216:44 https://doi.org/10.1007/s11214-020-00662-1 Dust-to-Gas and Refractory-to-Ice Mass Ratios of Comet 67P/Churyumov-Gerasimenko from Rosetta Observations Mathieu Choukroun1 · Kathrin Altwegg2 · Ekkehard Kührt3 · Nicolas Biver4 · Dominique Bockelée-Morvan4 · Joanna Dra˙ ˛zkowska5 · Alain Hérique6 · Martin Hilchenbach7 · Raphael Marschall8 · Martin Pätzold9 · Matthew G.G.T. Taylor10 · Nicolas Thomas2 Received: 17 May 2019 / Accepted: 19 March 2020 / Published online: 8 April 2020 © The Author(s) 2020 Abstract This chapter reviews the estimates of the dust-to-gas and refractory-to-ice mass ratios derived from Rosetta measurements in the lost materials and the nucleus of 67P/Churyumov-Gerasimenko, respectively. -
Rosetta Observations of Plasma and Dust at Comet 67P
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1989 Rosetta Observations of Plasma and Dust at Comet 67P FREDRIK LEFFE JOHANSSON ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 ISBN 978-91-513-1070-1 UPPSALA urn:nbn:se:uu:diva-425953 2020 Dissertation presented at Uppsala University to be publicly examined on Zoom, Friday, 15 January 2021 at 13:15 for the degree of Doctor of Philosophy. The examination will be conducted in English. Faculty examiner: Dr. Nicolas André (IRAP, Toulouse, France). Online defence: https://uu-se.zoom.us/j/67552597754 Contact person for questions about participation is Prof. Mats André 0707-792072 Abstract Johansson, F. L. 2020. Rosetta Observations of Plasma and Dust at Comet 67P. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1989. 35 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-513-1070-1. In-situ observations of cometary plasma are not made because they are easy. The historic ESA Rosetta mission was launched in 2004 and traversed space for ten years before arriving at comet 67P/Churyumov-Gerasimenko, which it studied in unprecedented detail for two years. For the Rosetta Dual Langmuir Probe Experiment (LAP), the challenge was increased by the sensors being situated on short booms near a significantly negatively charged spacecraft, which deflects low-energy charged particles away from our instrument. To disentangle the cometary plasma signature in our signal, we create a charging model for the particular design of the Rosetta spacecraft through 3D Particle-in-Cell/hybrid spacecraft-plasma interaction simulations, which also can be applicable to similarly designed spacecraft in cold plasma environments. -
MONITORING of AERODYNAMIC PRESSURES for VENUS EXPRESS in the UPPER ATMOSPHERE DURING DRAG EXPERIMENTS BASED on TELEMETRY Sylvain
MONITORING OF AERODYNAMIC PRESSURES FOR VENUS EXPRESS IN THE UPPER ATMOSPHERE DURING DRAG EXPERIMENTS BASED ON TELEMETRY Sylvain Damiani(1,2), Mathias Lauer(1), and Michael Müller(1) (1) ESA/ESOC; Robert-Bosch-Str. 5, 64293 Darmstadt, Germany; +49 6151900; [email protected] (2)GMV GmbH; Robert-Bosch-Str. 7, 64293 Darmstadt, Germany; +49 61513972970; [email protected] Abstract: The European Space Agency Venus Express spacecraft has to date successfully completed nine Aerodynamic Drag Experiment Campaigns designed in order to probe the planet's upper atmosphere over the North pole. The daily monitoring of the campaign is based on housekeeping telemetry. It consists of reducing the spacecraft dynamics in order to obtain a timely evolution of the aerodynamic torque over a pericenter passage, from which estimations of the accommodation coefficient, the dynamic pressure and the atmospheric density can be extracted. The observed surprising density fluctuations on short timescales justify the use of a conservative method to decide on the continuation of the experiments. Keywords: Venus Express, Drag Experiments, Attitude Dynamics, Aerodynamic Torque. 1. Introduction The European Space Agency's Venus Express spacecraft has been orbiting around Venus since 2006, and its mission has now been extended until 2014. During the extended mission, it has already successfully accomplished 9 Aerodynamic Drag Experiment campaigns until September 2012. Each campaign aims at probing the planet’s atmospheric density at high altitude and next to the North pole by lowering the orbit pericenter (down to 165 km of altitude), and observing its perturbations on both the orbit and the attitude of the probe. -
Forces, Light and Waves Mechanical Actions of Radiation
Forces, light and waves Mechanical actions of radiation Jacques Derouard « Emeritus Professor », LIPhy Example of comets Cf Hale-Bopp comet (1997) Exemple of comets Successive positions of a comet Sun Tail is in the direction opposite / Sun, as if repelled by the Sun radiation Comet trajectory A phenomenon known a long time ago... the first evidence of radiative pressure predicted several centuries later Peter Arpian « Astronomicum Caesareum » (1577) • Maxwell 1873 electromagnetic waves Energy flux associated with momentum flux (pressure): a progressive wave exerts Pressure = Energy flux (W/m2) / velocity of wave hence: Pressure (Pa) = Intensity (W/m2) / 3.10 8 (m/s) or: Pressure (nanoPa) = 3,3 . I (Watt/m2) • NB similar phenomenon with acoustic waves . Because the velocity of sound is (much) smaller than the velocity of light, acoustic radiative forces are potentially stronger. • Instead of pressure, one can consider forces: Force = Energy flux x surface / velocity hence Force = Intercepted power / wave velocity or: Force (nanoNewton) = 3,3 . P(Watt) Example of comet tail composed of particles radius r • I = 1 kWatt / m2 (cf Sun radiation at Earth) – opaque particle diameter ~ 1µm, mass ~ 10 -15 kg, surface ~ 10 -12 m2 – then P intercepted ~ 10 -9 Watt hence F ~ 3,3 10 -18 Newton comparable to gravitational attraction force of the sun at Earth-Sun distance Example of comet tail Influence of the particles size r • For opaque particles r >> 1µm – Intercepted power increases like the cross section ~ r2 thus less strongly than gravitational force that increases like the mass ~ r3 Example of comet tail Influence of the particles size r • For opaque particles r << 1µm – Solar radiation wavelength λ ~0,5µm – r << λ « Rayleigh regime» – Intercepted power varies like the cross section ~ r6 thus decreases much stronger than gravitational force ~ r3 Radiation pressure most effective for particles size ~ 1µm Another example Ashkin historical experiment (1970) A. -
Stardust Comet Dust Resembles Asteroid Materials 24 January 2008
Stardust comet dust resembles asteroid materials 24 January 2008 treasure trove of stardust from other stars and other ancient materials. But in the case of Wild 2, that simply is not the case. By comparing the Stardust samples to cometary interplanetary dust particles (CP IDPs), the team found that two silicate materials normally found in cometary IDPs, together with other primitive materials including presolar stardust grains from other stars, have not been found in the abundances that might be expected in a Kuiper Belt comet like Getting into the details: Stardust impact tracks and light Wild 2. The high-speed capture of the Stardust gas gun impacts of sulfide in aerogel both display metal particles may be partly responsible; but extra beads with sulfide rims indicating that GEMS-like objects refractory components that formed in the inner in Stardust are generated by impact mixing of comet solar nebula within a few astronomical units of the dust with silica aerogel. (left) Stardust GEMS-like sun, indicate that the Stardust material resembles material and (right) light gas gun shot GEM-like material. chondritic meteorites from the asteroid belt. GEMS in cometary IDPs do not contain sulfide-rimmed metal inclusions. [Image credit: Hope Ishii, LLNL] “The material is a lot less primitive and more altered than materials we have gathered through high altitude capture in our own stratosphere from a variety of comets,” said LLNL’s Hope Ishii, lead Contrary to expectations for a small icy body, much author of the research that appears in the Jan. 25 of the comet dust returned by the Stardust mission edition of the journal, Science. -
The Comet's Tale
THE COMET’S TALE Newsletter of the Comet Section of the British Astronomical Association Volume 9, No 1 (Issue 17), 2002 April JOEL HASTINGS METCALF MINISTER, HUMANITARIAN, ASTRONOMER Richard R Didick Joel Hastings Metcalf was born in The following account, taken used with either a single prism or Meadville, Pennsylvania, on from a newspaper article about a grating, both of which were January 4th, 1866, the son of him when he lived in Taunton, is provided. Lewis Herbert and Anna (Hicks) somewhat dubious since he Metcalf. Lewis was a Civil War actually bought the 7-inch In the observatory at Keesville, Veteran, a soldier who lost a leg refractor. "When but 14 years old the instrument was mounted in a at the first battle of "Bull Run" he built a telescope and ground very substantial dome, being and was held at Libby prison until out a lens with which he was able fastened to a fine cut granite base exchanged and discharged. to observe with success all the weighting about a ton. In a principal heavenly bodies. This February when Lake Champlain At the approximate age of 14, Joel was a small two-inch lens. His had frozen over, the whole outfit Metcalf borrowed Richard next attempt was a three-inch lens was loaded on sleds and started Proctor's book, Other Worlds and he later made one of three across the Lake on the ice. The Than Ours, from his Sunday and a half inches, which he ice was thick enough - but there school library which led him to an subsequently sold to Harvard are always long cracks in the interest in astronomy. -
19740026181.Pdf
DYNAMIC& AND PHOTOMETRIC INVESTIGATION OF COMETARY TYPE I1 TAILS Grant NGR 09-015-159 Semiannual Progress Report No. 6 For the period March 15 to September 14, 1974 Principal Investigator Dr. Zdenek Sekanina Prepared for . .-- National Aeronautics and Space Administration ; . Washington, D.C. 20546 q, ' ';'.. ',. : , , , - , .., ,: .,M, ._I _, . ..!..' , , .. ".. .,;-'/- Smithsonian Institution Astrophysical Observatory Cambridge, Massachusetts 02138 DYNAMICAL AND PHOTOMETRIC INVESTIGATION OF COMETARY TYPE 11 TAILS Grant NGR 09-015-159 Semiannual Progress Report No. 6 For the period March 15 to September 14, 1974 Principal Investigator Dr. Zdenek Sekanina Pre-ared for National Aeronautics and Space Administration Washington, D. C. 20546 Smithsonian Institut ion Astrophysical Observatory Sambridge, Massachusetts 02138 TABLE OF CONTENTS ABSTRACT ........................... iii PART A. COMPARISON OF THE WORKING MODEL FOR THE ANTITAIL OF COMET KOHOUTEK (1973f) WITH GROUND-BASED PHOTOGRAPHIC OBSERVATIONS . 1 1. Introduction ....................... 1 11. The Cerro Tololo photographs ............... 1 111. Photographic photometry of the Cerro Tololo plates. The technique ........................ 4 IV. Photographic photometry of the Cerro Tololo plates. The results ......................... V. Calibration stars for the Cerro Tololo plates ....... VI. Preliminary physical interpretation of the observed radial profiles of the antitail ................. VII. References ....................... PART B. OTHER ACTIVITIES IN THE REPORTED PERIOD ........... -
INFLUENCE of SOLAR RADIATION PRESSURE on ORBITAL ECCENTRICITY of a GRAVITY-GRADIENT-ORIENTED LENTICULAR SATELLITE by William M
NASA TECHNICAL NOTE NASA TN D-2715 e- e- - -- (5- / --I -=e3-m INFLUENCE OF SOLAR RADIATION PRESSURE ON ORBITAL ECCENTRICITY OF A GRAVITY-GRADIENT-ORIENTED LENTICULAR SATELLITE by William M. Adams, Jr., and Ward F. Hodge Langley Research Center Langley Station, Hampton, Va. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. 0 MARCH 1965 / t 1 TECH LIBRARY KAFB, "I I llllll11111 llllI11111111111111111l11 lilt 1111 0079733 INFLUENCE OF SOLAR RADIATION PRESSURE ON ORBITAL ECCENTRICITY OF A GRAVITY-GRADIENT-ORIENTED LENTICULAR SATELLITE By William M. Adams, Jr., and Ward F. Hodge Langley Research Center Langley Station, Hampton, Va. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION For sole by the Office of Technical Services, Deportment of Commerce, Woshington, D.C. 20230 -- Price $1.00 ... ~ I I INFLUENCE OF SOLAR RADIATION PRESSURE ON ORBITAL ECCENTRICITY OF A GRAVITY-GRADIENT-ORIENTED LENTICULAR SATEUITE By William M. Adams, Jr., and Ward F. HoQe Langley Research Center A method is presented for calculating the perturbations of the orbital elements of a low-density lenticular satellite due to solar radiation pressure. The necessary calculations are performed by means of the digital computer. Typ- ical results are presented for seven orbital inclinations ranging from 0' to ll3O for a perfectly absorptive satellite initially in a nearly circular 2,000- nautical-mile orbit. The information obtained indicates that the change in eccentricity caused by solar radiation pressure becomes large enough for all the inclinations con- sidered to cause attitude-control problems with the gravity-gradient stabiliza- tion system. A nearly circular orbit appears necessary for lenticular satel- lites since the ability of gravity gradient attitude control systems to damp the pitching libration induced by elliptic orbital motion is still in doubt.