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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. -
Cassini Update
Cassini Update Dr. Linda Spilker Cassini Project Scientist Outer Planets Assessment Group 22 February 2017 Sols%ce Mission Inclina%on Profile equator Saturn wrt Inclination 22 February 2017 LJS-3 Year 3 Key Flybys Since Aug. 2016 OPAG T124 – Titan flyby (1584 km) • November 13, 2016 • LAST Radio Science flyby • One of only two (cf. T106) ideal bistatic observations capturing Titan’s Northern Seas • First and only bistatic observation of Punga Mare • Western Kraken Mare not explored by RSS before T125 – Titan flyby (3158 km) • November 29, 2016 • LAST Optical Remote Sensing targeted flyby • VIMS high-resolution map of the North Pole looking for variations at and around the seas and lakes. • CIRS last opportunity for vertical profile determination of gases (e.g. water, aerosols) • UVIS limb viewing opportunity at the highest spatial resolution available outside of occultations 22 February 2017 4 Interior of Hexagon Turning “Less Blue” • Bluish to golden haze results from increased production of photochemical hazes as north pole approaches summer solstice. • Hexagon acts as a barrier that prevents haze particles outside hexagon from migrating inward. • 5 Refracting Atmosphere Saturn's• 22unlit February rings appear 2017 to bend as they pass behind the planet’s darkened limb due• 6 to refraction by Saturn's upper atmosphere. (Resolution 5 km/pixel) Dione Harbors A Subsurface Ocean Researchers at the Royal Observatory of Belgium reanalyzed Cassini RSS gravity data• 7 of Dione and predict a crust 100 km thick with a global ocean 10’s of km deep. Titan’s Summer Clouds Pose a Mystery Why would clouds on Titan be visible in VIMS images, but not in ISS images? ISS ISS VIMS High, thin cirrus clouds that are optically thicker than Titan’s atmospheric haze at longer VIMS wavelengths,• 22 February but optically 2017 thinner than the haze at shorter ISS wavelengths, could be• 8 detected by VIMS while simultaneously lost in the haze to ISS. -
Models of a Protoplanetary Disk Forming In-Situ the Galilean And
Models of a protoplanetary disk forming in-situ the Galilean and smaller nearby satellites before Jupiter is formed Dimitris M. Christodoulou1, 2 and Demosthenes Kazanas3 1 Lowell Center for Space Science and Technology, University of Massachusetts Lowell, Lowell, MA, 01854, USA. 2 Dept. of Mathematical Sciences, Univ. of Massachusetts Lowell, Lowell, MA, 01854, USA. E-mail: [email protected] 3 NASA/GSFC, Laboratory for High-Energy Astrophysics, Code 663, Greenbelt, MD 20771, USA. E-mail: [email protected] March 5, 2019 ABSTRACT We fit an isothermal oscillatory density model of Jupiter’s protoplanetary disk to the present-day Galilean and other nearby satellites and we determine the radial scale length of the disk, the equation of state and the central density of the primordial gas, and the rotational state of the Jovian nebula. Although the radial density profile of Jupiter’s disk was similar to that of the solar nebula, its rotational support against self-gravity was very low, a property that also guaranteed its long-term stability against self-gravity induced instabilities for millions of years. Keywords. planets and satellites: dynamical evolution and stability—planets and satellites: formation—protoplanetary disks 1. Introduction 2. Intrinsic and Oscillatory Solutions of the Isothermal Lane-Emden Equation with Rotation In previous work (Christodoulou & Kazanas 2019a,b), we pre- sented and discussed an isothermal model of the solar nebula 2.1. Intrinsic Analytical Solutions capable of forming protoplanets long before the Sun was actu- The isothermal Lane-Emden equation (Lane 1869; Emden 1907) ally formed, very much as currently observed in high-resolution with rotation (Christodoulou & Kazanas 2019a) takes the form (∼1-5 AU) observations of protostellar disks by the ALMA tele- of a second-order nonlinear inhomogeneous equation, viz. -
JUICE Red Book
ESA/SRE(2014)1 September 2014 JUICE JUpiter ICy moons Explorer Exploring the emergence of habitable worlds around gas giants Definition Study Report European Space Agency 1 This page left intentionally blank 2 Mission Description Jupiter Icy Moons Explorer Key science goals The emergence of habitable worlds around gas giants Characterise Ganymede, Europa and Callisto as planetary objects and potential habitats Explore the Jupiter system as an archetype for gas giants Payload Ten instruments Laser Altimeter Radio Science Experiment Ice Penetrating Radar Visible-Infrared Hyperspectral Imaging Spectrometer Ultraviolet Imaging Spectrograph Imaging System Magnetometer Particle Package Submillimetre Wave Instrument Radio and Plasma Wave Instrument Overall mission profile 06/2022 - Launch by Ariane-5 ECA + EVEE Cruise 01/2030 - Jupiter orbit insertion Jupiter tour Transfer to Callisto (11 months) Europa phase: 2 Europa and 3 Callisto flybys (1 month) Jupiter High Latitude Phase: 9 Callisto flybys (9 months) Transfer to Ganymede (11 months) 09/2032 – Ganymede orbit insertion Ganymede tour Elliptical and high altitude circular phases (5 months) Low altitude (500 km) circular orbit (4 months) 06/2033 – End of nominal mission Spacecraft 3-axis stabilised Power: solar panels: ~900 W HGA: ~3 m, body fixed X and Ka bands Downlink ≥ 1.4 Gbit/day High Δv capability (2700 m/s) Radiation tolerance: 50 krad at equipment level Dry mass: ~1800 kg Ground TM stations ESTRAC network Key mission drivers Radiation tolerance and technology Power budget and solar arrays challenges Mass budget Responsibilities ESA: manufacturing, launch, operations of the spacecraft and data archiving PI Teams: science payload provision, operations, and data analysis 3 Foreword The JUICE (JUpiter ICy moon Explorer) mission, selected by ESA in May 2012 to be the first large mission within the Cosmic Vision Program 2015–2025, will provide the most comprehensive exploration to date of the Jovian system in all its complexity, with particular emphasis on Ganymede as a planetary body and potential habitat. -
Eye Juggling: a Methodology for Interpreting Stories
Eye Juggling: A Methodology for Interpreting Stories Eye Juggling Outline With modifications and additions, as an excerpt from: Rodney Frey. 1995. Eye Juggling: Seeing the World Through a Looking Glass and a Glass Pane. University Press of America: London, and other sources. The Eye Juggler There is an old man, with long, black braids. He stands there, beside that tall cedar tree, singing a song. As he sings that song, what should happen..., his eyes pop out of his head. He continues singing that song and his eyes go up the side of the tree to the top branch. There those eyes look to the east. Then they turn and look to the south. The old man with empty sockets in his head continues that song. From the top of the tree the eyes look to the west. And then the eyes turn once more and look to the north, the fourth direction. As the old man with long, black braids sings that song, who should come along the path there but Coyote, down on his luck. He sees the old man standing there and decides to pay him a visit. He's been out there in those hills a long time. But as Coyote gets a little closer he realizes that there is something odd about this old man. He's seen some strange things out there in those hills but nothing like this. The old man is singing his eyes to the sky! Now Coyote, who's been down on his luck, realizes a good thing when he sees it. -
What's Happening at the IJA ?
THE INTERNATIONAL JUGGLERS’ ASSOCIATION October 2007 IJA e-newsletter editor: Don Lewis (email: [email protected]) Renew at http://www.juggle.org/renew What’s Happening at the IJA ? In This Issue: 2008 Lexington IJA Festival Help Wanted Have You Moved, or Gotten a New Email Address? Treasury Remember, the only way to ensure that you don't miss a World Juggling Day single issue of JUGGLE magazine is to give us your new Marketing the IJA address. The USPS will generally not forward JUGGLE Joggling Record magazine. Insurance To update your mailing address, email, or phone, please Regional Festivals send email to [email protected] or call TurboFest - Quebec City 415-596-3307 or write to: IJA, PO Box 7307, Austin, TX 78713-7307 USA. World Circus Year 2008 IJA Festival, Lexington, Kentucky The Hyatt is connected to the convention center. The convention center has a food court and shops and they are Lexington Notes by Richard Kennison open on a daily basis. There is a vibrant downtown area right Everyone, around the convention center. I just spent two days in Lexington, KY. I am very thrilled to tell The convention center contact person, the hotel contact person you that I think it is a wonderful site. I will not go into long and the theatre contact person are all professional and excited details here but: that we are coming. Bond Jacobs—the visitors bureau contact You can park your car (for free if you stay the the Hyatt) and person is an asset and will go the extra mile for us. -
Exep Science Plan Appendix (SPA) (This Document)
ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 1 of 61 Created By: David A. Breda Date Program TDEM System Engineer Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Nick Siegler Date Program Chief Technologist Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Concurred By: Dr. Gary Blackwood Date Program Manager Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology EXOPDr.LANET Douglas Hudgins E XPLORATION PROGRAMDate Program Scientist Exoplanet Exploration Program ScienceScience Plan Mission DirectorateAppendix NASA Headquarters Karl Stapelfeldt, Program Chief Scientist Eric Mamajek, Deputy Program Chief Scientist Exoplanet Exploration Program JPL CL#19-0790 JPL Document No: 1735632 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 2 of 61 Approved by: Dr. Gary Blackwood Date Program Manager, Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory Dr. Douglas Hudgins Date Program Scientist Exoplanet Exploration Program Science Mission Directorate NASA Headquarters Created by: Dr. Karl Stapelfeldt Chief Program Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Eric Mamajek Deputy Program Chief Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2018 California Institute of Technology. Government sponsorship acknowledged. Exoplanet Exploration Program JPL CL#19-0790 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 3 of 61 Table of Contents 1. -
~Mqltltrsity of Hawaif Librar?
~ID ~mqltltRSITY OF HAWAIf lIBRAR? MISSING PONO A TIlESIS SUBMITTED TO THE GRADUATE DIVISION OF TIlE UNIVERSITY OF HAWAn PARTIAL FULFILLMENT OF TIlE REQUIREMENTS FOR TIlE DEGREE OF MASTER OF ARTS IN ENGLISH MAY 2003 By Christopher R. Kelsey Thesis Committee: Ian McMillan, Chairperson Robert Shapard Paul Lyons Rodney Morales iii TABLE OF CONTENTS Haole Boss............. 1 Missing Pono.......................................................................................... 17 The Clearing................. 33 Rock of Ages.... 52 The Risk.................................................................................................. 69 Or ItMight Be you................................................................................ 85 1 Haole Boss Pale pink hydraulic fluid splattered across the inside of Taylor Beck's left wrist, bounced off the bib of his mocha-brown Carhart overalls, and plopped on the toe of his dirty boots. He imagined it looked like haole blood. But it wasn't his or anyone else's. He'd struggled all his life to avoid being labeled a haole. He knew everybody's blood was the same color, though it looked like it could've been spilled from a white man's veins. But the machine didn't bleed, it leaked. Taylor squinted up at the greasy stainless-steel mast of the stand-up fork lift. His forearm shielded his eyes from the drips but blocked his vision, and he brushed the graying blonde strands off his forehead. A tightly banded braid kept his shoulder-length hair from sticking in his moustache and beard like velcro. He rolled his tight neck muscles, shrugged his husky shoulders and stepped out of the machine to get away from the harsh glare of the big halogen light. He figured it must be that hose clamp again. -
The Rings and Inner Moons of Uranus and Neptune: Recent Advances and Open Questions
Workshop on the Study of the Ice Giant Planets (2014) 2031.pdf THE RINGS AND INNER MOONS OF URANUS AND NEPTUNE: RECENT ADVANCES AND OPEN QUESTIONS. Mark R. Showalter1, 1SETI Institute (189 Bernardo Avenue, Mountain View, CA 94043, mshowal- [email protected]! ). The legacy of the Voyager mission still dominates patterns or “modes” seem to require ongoing perturba- our knowledge of the Uranus and Neptune ring-moon tions. It has long been hypothesized that numerous systems. That legacy includes the first clear images of small, unseen ring-moons are responsible, just as the nine narrow, dense Uranian rings and of the ring- Ophelia and Cordelia “shepherd” ring ε. However, arcs of Neptune. Voyager’s cameras also first revealed none of the missing moons were seen by Voyager, sug- eleven small, inner moons at Uranus and six at Nep- gesting that they must be quite small. Furthermore, the tune. The interplay between these rings and moons absence of moons in most of the gaps of Saturn’s rings, continues to raise fundamental dynamical questions; after a decade-long search by Cassini’s cameras, sug- each moon and each ring contributes a piece of the gests that confinement mechanisms other than shep- story of how these systems formed and evolved. herding might be viable. However, the details of these Nevertheless, Earth-based observations have pro- processes are unknown. vided and continue to provide invaluable new insights The outermost µ ring of Uranus shares its orbit into the behavior of these systems. Our most detailed with the tiny moon Mab. Keck and Hubble images knowledge of the rings’ geometry has come from spanning the visual and near-infrared reveal that this Earth-based stellar occultations; one fortuitous stellar ring is distinctly blue, unlike any other ring in the solar alignment revealed the moon Larissa well before Voy- system except one—Saturn’s E ring. -
The Coriolis Force and the Rattleback
The Coriolis Force and the Rattleback Frederick David Tombe, Belfast, Northern Ireland, United Kingdom, [email protected] 17th December 2010 Abstract. The rattleback (Celtic Stone) is the most mysterious phenomenon in classical mechanics. It reverses its angular momentum by inducing a Coriolis pressure from the dense background sea of rotating electron-positron dipoles which is the medium for the propagation of light. [1] Magnets and Rattlebacks I. Magnets and rattlebacks share in common the fact that they involve a mutual alignment of the spin moments of their constituent atoms and molecules. They differ however in that rattlebacks involve a rotation on the large scale in order to bring this alignment about. In magnetic materials, the induced spin alignment results in a linear force, whereas in rattlebacks, the induced spin alignment results in a reversal torque which opposes the initial rotation. Another important difference is that rattlebacks are generally made of materials which are not as dense as magnetic materials. [2] Gravity and Friction II. Gravity acts vertically downwards and so the reversal torque in a rattleback cannot be sourced in gravity. Sliding friction is involved in that it dissipates the entire motion, but sliding friction by its nature is not something that could cause a reversal torque. Static friction is necessary in order to enable the rocking stage of the rattleback’s cycle. Without static friction, a rattleback will not work. However, static friction by its nature is not something that could actually go as far as to cause a reversal torque. 1 Forging a Torque by Mathematical Manipulation III. -
The Convention Ear 58 (Y)Ears of Telling It Like It Isn’T!
The Convention Ear 58 (Y)Ears of Telling It Like It Isn’t! Wednesday, July 25, 2018 Volume LIX, Issue III 25 Hour Convention Coverage Astronomers, Classicists Scramble to Invent Twelve More Stories About Zeus in Order to Name New Moons of Jupiter That’s Entertainment! Results With the recent discovery of twelve new moons around Jupiter, astronomers Congratulations to the following dele- and classicists have put aside their differences (they’ve agreed to spell it gates who have been selected to per- “Jupiter” not “Iuppiter”) to take on the challenge of naming the celestial bod- ies. As is tradition, the new moons will be named after various loves the king form in That's Entertainment! of the gods was said to have had; the only problem is, after 53 moons, we’ve Soren Adams (KY) run out of names. Madelyn Bedard & Ruth Weaver (MA) “This is a different kind of nomenclature problem than what we’re used to,” Cameron Crowley (TX) said astronomer Dr. Joey Chatelain, who looks at the sky for a living. “We’ve Sophia Dort (VA) already used Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Cal- Jeffrey Frenkel-Popell (CA) listo,” <we left at this point, did laundry, got lunch, then came back - the list Keon Honaryar (CA) was still going> “... Sinope, Sponde, Autonoe, Megaclite, and S/2003 J 2. We Kiana Hu (CA) simply don’t have any more names to use.” Illinois Dance Troupe (IL) To solve this problem, astronomers have turned to classicists for help. “The Owen Lockwood (OH) answer is simple,” said one leading Classics professor, who wished to remain Akhila Nataraj (FL) anonymous. -
Abstracts of the 50Th DDA Meeting (Boulder, CO)
Abstracts of the 50th DDA Meeting (Boulder, CO) American Astronomical Society June, 2019 100 — Dynamics on Asteroids break-up event around a Lagrange point. 100.01 — Simulations of a Synthetic Eurybates 100.02 — High-Fidelity Testing of Binary Asteroid Collisional Family Formation with Applications to 1999 KW4 Timothy Holt1; David Nesvorny2; Jonathan Horner1; Alex B. Davis1; Daniel Scheeres1 Rachel King1; Brad Carter1; Leigh Brookshaw1 1 Aerospace Engineering Sciences, University of Colorado Boulder 1 Centre for Astrophysics, University of Southern Queensland (Boulder, Colorado, United States) (Longmont, Colorado, United States) 2 Southwest Research Institute (Boulder, Connecticut, United The commonly accepted formation process for asym- States) metric binary asteroids is the spin up and eventual fission of rubble pile asteroids as proposed by Walsh, Of the six recognized collisional families in the Jo- Richardson and Michel (Walsh et al., Nature 2008) vian Trojan swarms, the Eurybates family is the and Scheeres (Scheeres, Icarus 2007). In this theory largest, with over 200 recognized members. Located a rubble pile asteroid is spun up by YORP until it around the Jovian L4 Lagrange point, librations of reaches a critical spin rate and experiences a mass the members make this family an interesting study shedding event forming a close, low-eccentricity in orbital dynamics. The Jovian Trojans are thought satellite. Further work by Jacobson and Scheeres to have been captured during an early period of in- used a planar, two-ellipsoid model to analyze the stability in the Solar system. The parent body of the evolutionary pathways of such a formation event family, 3548 Eurybates is one of the targets for the from the moment the bodies initially fission (Jacob- LUCY spacecraft, and our work will provide a dy- son and Scheeres, Icarus 2011).