Natural Moons Dynamics and Astrometry
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![Arxiv:1912.09192V2 [Astro-Ph.EP] 24 Feb 2020](https://docslib.b-cdn.net/cover/2925/arxiv-1912-09192v2-astro-ph-ep-24-feb-2020-2925.webp)
Arxiv:1912.09192V2 [Astro-Ph.EP] 24 Feb 2020
Draft version February 25, 2020 Typeset using LATEX preprint style in AASTeX62 Photometric analyses of Saturn's small moons: Aegaeon, Methone and Pallene are dark; Helene and Calypso are bright. M. M. Hedman,1 P. Helfenstein,2 R. O. Chancia,1, 3 P. Thomas,2 E. Roussos,4 C. Paranicas,5 and A. J. Verbiscer6 1Department of Physics, University of Idaho, Moscow, ID 83844 2Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca NY 14853 3Center for Imaging Science, Rochester Institute of Technology, Rochester NY 14623 4Max Planck Institute for Solar System Research, G¨ottingen,Germany 37077 5APL, John Hopkins University, Laurel MD 20723 6Department of Astronomy, University of Virginia, Charlottesville, VA 22904 ABSTRACT We examine the surface brightnesses of Saturn's smaller satellites using a photometric model that explicitly accounts for their elongated shapes and thus facilitates compar- isons among different moons. Analyses of Cassini imaging data with this model reveals that the moons Aegaeon, Methone and Pallene are darker than one would expect given trends previously observed among the nearby mid-sized satellites. On the other hand, the trojan moons Calypso and Helene have substantially brighter surfaces than their co-orbital companions Tethys and Dione. These observations are inconsistent with the moons' surface brightnesses being entirely controlled by the local flux of E-ring par- ticles, and therefore strongly imply that other phenomena are affecting their surface properties. The darkness of Aegaeon, Methone and Pallene is correlated with the fluxes of high-energy protons, implying that high-energy radiation is responsible for darkening these small moons. Meanwhile, Prometheus and Pandora appear to be brightened by their interactions with nearby dusty F ring, implying that enhanced dust fluxes are most likely responsible for Calypso's and Helene's excess brightness. -
![Arxiv:1303.4129V2 [Gr-Qc] 8 May 2013 Counters with Supermassive Black Holes (SMBH) of Mass in Some Preceding Tidal Event](https://docslib.b-cdn.net/cover/1186/arxiv-1303-4129v2-gr-qc-8-may-2013-counters-with-supermassive-black-holes-smbh-of-mass-in-some-preceding-tidal-event-51186.webp)
Arxiv:1303.4129V2 [Gr-Qc] 8 May 2013 Counters with Supermassive Black Holes (SMBH) of Mass in Some Preceding Tidal Event
Relativistic effects in the tidal interaction between a white dwarf and a massive black hole in Fermi normal coordinates Roseanne M. Cheng∗ Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA and Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599, USA Charles R. Evansy Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (Received 17 March 2013; published 6 May 2013) We consider tidal encounters between a white dwarf and an intermediate mass black hole. Both weak encounters and those at the threshold of disruption are modeled. The numerical code combines mesh-based hydrodynamics, a spectral method solution of the self-gravity, and a general relativistic Fermi normal coordinate system that follows the star and debris. Fermi normal coordinates provide an expansion of the black hole tidal field that includes quadrupole and higher multipole moments and relativistic corrections. We compute the mass loss from the white dwarf that occurs in weak tidal encounters. Secondly, we compute carefully the energy deposition onto the star, examining the effects of nonradial and radial mode excitation, surface layer heating, mass loss, and relativistic orbital motion. We find evidence of a slight relativistic suppression in tidal energy transfer. Tidal energy deposition is compared to orbital energy loss due to gravitational bremsstrahlung and the combined losses are used to estimate tidal capture orbits. Heating and partial mass stripping will lead to an expansion of the white dwarf, making it easier for the star to be tidally disrupted on the next passage. -
Astrometry and Tidal Migration V
Astrometry and tidal migration V. Lainey (JPL/IMCCE), J.Fuller (Caltech) [email protected] -KISS workshop- October 16th 2018 Astrometric measurements Example 1: classical astrometric observations (the most direct measurement) Images suitable for astrometric reduction from ground or space Tajeddine et al. 2013 Mallama et al. 2004 CCD obs from ground Cassini ISS image HST image Photographic plates (not used anymore BUT re-reduction now benefits from modern scanning machine) Astrometric measurements Example 2: photometric measurements (undirect astrometric measurement) Eclipses by the planet Mutual phenomenae (barely used those days…) (arising every six years) By modeling the event, one can solve for mid-time event and minimum distance between the center of flux figure of the objects à astrometric measure Time (hours) Astrometric measurements Example 3: other measurements (non exhaustive list) During flybys of moons, one can (sometimes!) solved for a correction on the moon ephemeris Radio science measurement (orbital tracking) Radar measurement (distance measurement between back and forth radio wave travel) Morgado et al. 2016 Mutual approximation (measure of moons’ distance rate) Astrometric accuracy Remark: 1- Accuracy of specific techniques STRONGLY depends on the epoch 2- Total numBer of oBservations per oBservation opportunity can Be VERY different For the Galilean system: (numbers are purely indicative) From ground Direct imaging: 100 mas (300 km) to 20 mas (60 km) –stacking techniques- Mutual events: typically 20-80 mas -
Tidal Heating in Enceladus
Icarus 188 (2007) 535–539 www.elsevier.com/locate/icarus Note Tidal heating in Enceladus Jennifer Meyer ∗, Jack Wisdom Massachusetts Institute of Technology, Cambridge, MA 02139, USA Received 20 February 2007; revised 3 March 2007 Available online 19 March 2007 Abstract The heating in Enceladus in an equilibrium resonant configuration with other saturnian satellites can be estimated independently of the physical properties of Enceladus. We find that equilibrium tidal heating cannot account for the heat that is observed to be coming from Enceladus. Equilibrium heating in possible past resonances likewise cannot explain prior resurfacing events. © 2007 Elsevier Inc. All rights reserved. Keywords: Enceladus; Saturn, satellites; Satellites, dynamics; Resonances, orbital; Tides, solid body 1. Introduction One mechanism for heating Enceladus that passes the Mimas test is the secondary spin–orbit libration model (Wisdom, 2004). Fits to the shape of Enceladus is a puzzle. Cassini observed active plumes emanating from Enceladus from Voyager images indicated that the frequency of small amplitude Enceladus (Porco et al., 2006). The plumes consist almost entirely of water oscillations about the Saturn-pointing orientation of Enceladus was about 1/3 vapor, with entrained water ice particles of typical size 1 µm. Models of the of the orbital frequency. In the phase-space of the spin–orbit problem near the plumes suggest the existence of liquid water as close as 7 m to the surface damped synchronous state the stable equilibrium bifurcates into a period-tripled (Porco et al., 2006). An alternate model has the water originate in a clathrate state. If Enceladus were trapped in this bifurcated state, then there could be sev- reservoir (Kieffer et al., 2006). -
The Orbits of Saturn's Small Satellites Derived From
The Astronomical Journal, 132:692–710, 2006 August A # 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE ORBITS OF SATURN’S SMALL SATELLITES DERIVED FROM COMBINED HISTORIC AND CASSINI IMAGING OBSERVATIONS J. N. Spitale CICLOPS, Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301; [email protected] R. A. Jacobson Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 C. C. Porco CICLOPS, Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 and W. M. Owen, Jr. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 Received 2006 February 28; accepted 2006 April 12 ABSTRACT We report on the orbits of the small, inner Saturnian satellites, either recovered or newly discovered in recent Cassini imaging observations. The orbits presented here reflect improvements over our previously published values in that the time base of Cassini observations has been extended, and numerical orbital integrations have been performed in those cases in which simple precessing elliptical, inclined orbit solutions were found to be inadequate. Using combined Cassini and Voyager observations, we obtain an eccentricity for Pan 7 times smaller than previously reported because of the predominance of higher quality Cassini data in the fit. The orbit of the small satellite (S/2005 S1 [Daphnis]) discovered by Cassini in the Keeler gap in the outer A ring appears to be circular and coplanar; no external perturbations are appar- ent. Refined orbits of Atlas, Prometheus, Pandora, Janus, and Epimetheus are based on Cassini , Voyager, Hubble Space Telescope, and Earth-based data and a numerical integration perturbed by all the massive satellites and each other. -
Technology Development for Future Sparse Aperture Telescopes and Interferometers in Space
A Technology Whitepaper submitted to the 2010 Decadal Survey Technology Development for Future Sparse Aperture Telescopes and Interferometers in Space 24 March 2009 NASA Centers: GSFC: Kenneth G. Carpenter, Keith Gendreau, Jesse Leitner, Richard Lyon, Eric Stoneking MSFC: H. Philip Stahl Industrial Partners: Aurora Flight Systems: Joe Parrish LMATC: Carolus J. Schrijver, Robert Woodruff NGST – Amy Lo, Chuck Lillie Seabrook Engineering: David Mozurkewich University/Astronomical Institute Partners: College de France: Antoine Labeyrie MIT: David Miller NOAO: Ken Mighell SAO: Margarita Karovska, James Phillips STScI: Ronald J. Allen UCO/Boulder: Webster Cash Abstract We describe the major technology development efforts that need to occur throughout the 2010 decade in order to enable a wide variety of sparse aperture and interferometric missions in the following decade. These missions are critical to achieving the next major revolution in astronomical observations by dramatically increasing the achievable angular resolution by more than 2 orders of magnitude, over wavelengths stretching from the x-ray and ultraviolet into the infrared and sub-mm. These observations can only be provided by long-baseline interferometers or sparse aperture telescopes in space, since the aperture diameters required are in excess of 500m - a regime in which monolithic or segmented designs are not and will not be feasible - and since they require observations at wavelengths not accessible from the ground. The technology developments needed for these missions are challenging, but eminently feasible with a reasonable investment over the next decade to enable flight in the 2025+ timeframe. That investment would enable tremendous gains in our understanding of the structure of the Universe and of its individual components in ways both anticipated and unimaginable today. -
Effect of Mantle and Ocean Tides on the Earth’S Rotation Rate
A&A 493, 325–330 (2009) Astronomy DOI: 10.1051/0004-6361:200810343 & c ESO 2008 Astrophysics Effect of mantle and ocean tides on the Earth’s rotation rate P. M. Mathews1 andS.B.Lambert2 1 Department of Theoretical Physics, University of Madras, Chennai 600025, India 2 Observatoire de Paris, Département Systèmes de Référence Temps Espace (SYRTE), CNRS/UMR8630, 75014 Paris, France e-mail: [email protected] Received 7 June 2008 / Accepted 17 October 2008 ABSTRACT Aims. We aim to compute the rate of increase of the length of day (LOD) due to the axial component of the torque produced by the tide generating potential acting on the tidal redistribution of matter in the oceans and the solid Earth. Methods. We use an extension of the formalism applied to precession-nutation in a previous work to the problem of length of day variations of an inelastic Earth with a fluid core and oceans. Expressions for the second order axial torque produced by the tesseral and sectorial tide-generating potentials on the tidal increments to the Earth’s inertia tensor are derived and used in the axial component of the Euler-Liouville equations to arrive at the rate of increase of the LOD. Results. The increase in the LOD, produced by the same dissipative mechanisms as in the theoretical work on which the IAU 2000 nutation model is based and in our recent computation of second order effects, is found to be at a rate of 2.35 ms/cy due to the ocean tides, and 0.15 ms/cy due to solid Earth tides, in reasonable agreement with estimates made by other methods. -
Viscoelastic Dissipation Models and Geophysical Data
Confidential manuscript submitted to JGR-Planets 1 Tidal Response of Mars Constrained from Laboratory-based 2 Viscoelastic Dissipation Models and Geophysical Data 1 2;1 3 3 1 3 A. Bagheri , A. Khan , D. Al-Attar , O. Crawford , D. Giardini 1 4 Institute of Geophysics, ETH Zürich, Zürich, Switzerland 2 5 Institute of Theoretical Physics, University of Zürich, Zürich, Switzerland 3 6 Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Cambridge, UK 7 Key Points: • 8 We present a method for determining the planetary tidal response using laboratory- 9 based viscoelastic models and apply it to Mars. • 10 Maxwellian rheology results in considerably biased (low) viscosities and should be 11 used with caution when studying tidal dissipation. • 12 Mars’ rheology and interior structure will be further constrained from InSight mea- 13 surements of tidal phase lags at distinct periods. Corresponding author: Amirhossein Bagheri, [email protected] –1– Confidential manuscript submitted to JGR-Planets 14 Abstract 15 We employ laboratory-based grain-size- and temperature-sensitive rheological models to 16 describe the viscoelastic behavior of terrestrial bodies with focus on Mars. Shear modulus 17 reduction and attenuation related to viscoelastic relaxation occur as a result of diffusion- 18 and dislocation-related creep and grain-boundary processes. We consider five rheological 19 models, including extended Burgers, Andrade, Sundberg-Cooper, a power-law approxima- 20 tion, and Maxwell, and determine Martian tidal response. However, the question of which 21 model provides the most appropriate description of dissipation in planetary bodies, re- 22 mains an open issue. To examine this, crust and mantle models (density and elasticity) are 23 computed self-consistently through phase equilibrium calculations as a function of pres- 24 sure, temperature, and bulk composition, whereas core properties are based on an Fe-FeS 25 parameterisation. -
Titan and the Moons of Saturn Telesto Titan
The Icy Moons and the Extended Habitable Zone Europa Interior Models Other Types of Habitable Zones Water requires heat and pressure to remain stable as a liquid Extended Habitable Zones • You do not need sunlight. • You do need liquid water • You do need an energy source. Saturn and its Satellites • Saturn is nearly twice as far from the Sun as Jupiter • Saturn gets ~30% of Jupiter’s sunlight: It is commensurately colder Prometheus • Saturn has 82 known satellites (plus the rings) • 7 major • 27 regular • 4 Trojan • 55 irregular • Others in rings Titan • Titan is nearly as large as Ganymede Titan and the Moons of Saturn Telesto Titan Prometheus Dione Titan Janus Pandora Enceladus Mimas Rhea Pan • . • . Titan The second-largest moon in the Solar System The only moon with a substantial atmosphere 90% N2 + CH4, Ar, C2H6, C3H8, C2H2, HCN, CO2 Equilibrium Temperatures 2 1/4 Recall that TEQ ~ (L*/d ) Planet Distance (au) TEQ (K) Mercury 0.38 400 Venus 0.72 291 Earth 1.00 247 Mars 1.52 200 Jupiter 5.20 108 Saturn 9.53 80 Uranus 19.2 56 Neptune 30.1 45 The Atmosphere of Titan Pressure: 1.5 bars Temperature: 95 K Condensation sequence: • Jovian Moons: H2O ice • Saturnian Moons: NH3, CH4 2NH3 + sunlight è N2 + 3H2 CH4 + sunlight è CH, CH2 Implications of Methane Free CH4 requires replenishment • Liquid methane on the surface? Hazy atmosphere/clouds may suggest methane/ ethane precipitation. The freezing points of CH4 and C2H6 are 91 and 92K, respectively. (Titan has a mean temperature of 95K) (Liquid natural gas anyone?) This atmosphere may resemble the primordial terrestrial atmosphere. -
A Possible Explanation of the Secular Increase of the Astronomical Unit 1
T. Miura 1 A possible explanation of the secular increase of the astronomical unit Takaho Miura(a), Hideki Arakida, (b) Masumi Kasai(a) and Syuichi Kuramata(a) (a)Faculty of Science and Technology,Hirosaki University, 3 bunkyo-cyo Hirosaki, Aomori, 036-8561, Japan (b)Education and integrate science academy, Waseda University,1 waseda sinjuku Tokyo, Japan Abstract We give an idea and the order-of-magnitude estimations to explain the recently re- ported secular increase of the Astronomical Unit (AU) by Krasinsky and Brumberg (2004). The idea proposed is analogous to the tidal acceleration in the Earth-Moon system, which is based on the conservation of the total angular momentum and we apply this scenario to the Sun-planets system. Assuming the existence of some tidal interactions that transfer the rotational angular momentum of the Sun and using re- d ported value of the positive secular trend in the astronomical unit, dt 15 4(m/s),the suggested change in the period of rotation of the Sun is about 21(ms/cy) in the case that the orbits of the eight planets have the same "expansionrate."This value is suf- ficiently small, and at present it seems there are no observational data which exclude this possibility. Effects of the change in the Sun's moment of inertia is also investi- gated. It is pointed out that the change in the moment of inertia due to the radiative mass loss by the Sun may be responsible for the secular increase of AU, if the orbital "expansion"is happening only in the inner planets system. -
The Search for Exomoons and the Characterization of Exoplanet Atmospheres
Corso di Laurea Specialistica in Astronomia e Astrofisica The search for exomoons and the characterization of exoplanet atmospheres Relatore interno : dott. Alessandro Melchiorri Relatore esterno : dott.ssa Giovanna Tinetti Candidato: Giammarco Campanella Anno Accademico 2008/2009 The search for exomoons and the characterization of exoplanet atmospheres Giammarco Campanella Dipartimento di Fisica Università degli studi di Roma “La Sapienza” Associate at Department of Physics & Astronomy University College London A thesis submitted for the MSc Degree in Astronomy and Astrophysics September 4th, 2009 Università degli Studi di Roma ―La Sapienza‖ Abstract THE SEARCH FOR EXOMOONS AND THE CHARACTERIZATION OF EXOPLANET ATMOSPHERES by Giammarco Campanella Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Our knowledge of extrasolar planets has grown exponentially, from our understanding of their formation and evolution to the development of different methods to detect them. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. The structure of the thesis is as follows. In Chapter 1 an historical background is provided and some general aspects about ongoing situation in the research field of extrasolar planets are shown. In Chapter 2, various detection techniques such as radial velocity, microlensing, astrometry, circumstellar disks, pulsar timing and magnetospheric emission are described. A special emphasis is given to the transit photometry technique and to the two already operational transit space missions, CoRoT and Kepler. -
Lesson -14 the Outer Space
Lesson -14 The Outer Space Q1. Fill in the blanks: 1. The moon rotates around the earth. 2. A group of stars is called constellation. 3. Moon is the natural satellite of earth. 4. When we cannot see the moon in the sky, it is called amavasya. 5. The sun is a star. Q2. Choose the correct answer: 1. Huge glowing balls of fire are called___________. a) Satellites b) sun 2. The moon rotates around the _____________. a) Earth b) Mars 3. A group of stars forms a ___________. a) Satellite b) constellation 4. We can see full moon on ___________. a) Amavasya b) purnima 5. The moon gets its light from the _____________. a) Earth b) sun Q3. True or False: 1. Stars go away from the sky during the day – False. 2. Moon gets its light from earth –False. 3. We can live on moon –False. 4. Earth is the first planet from the sun – False. 5. Sun gives us heat and light – True. Q4. Match the following: 1. Sun - dwarf planet (5) 2. Moon - constellation (4) 3. Earth - satellite (2) 4. Leo - star (1) 5. Pluto - third planet from sun ( 3) Q5. Give two examples each of: 1. Heavenly bodies: Ans: (i) Moon (ii) planets. 2. Planets: Ans: (i) Earth (ii) mars 3. Stars: Ans: (i) Sun (ii) pole star 4. Constellations: Ans: (i) orion (ii) Leo 5. Satellites: Ans: (i) moon (ii)Earth Q6. Short answer: 1. What does the universe consist of? Ans: The universe consists of heavenly bodies like stars, planets and moon. 2.