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Water Masers in the Saturnian System
A&A 494, L1–L4 (2009) Astronomy DOI: 10.1051/0004-6361:200811186 & c ESO 2009 Astrophysics Letter to the Editor Water masers in the Saturnian system S. V. Pogrebenko1,L.I.Gurvits1, M. Elitzur2,C.B.Cosmovici3,I.M.Avruch1,4, S. Montebugnoli5 , E. Salerno5, S. Pluchino3,5, G. Maccaferri5, A. Mujunen6, J. Ritakari6, J. Wagner6,G.Molera6, and M. Uunila6 1 Joint Institute for VLBI in Europe, PO Box 2, 7990 AA Dwingeloo, The Netherlands e-mail: [pogrebenko;lgurvits]@jive.nl 2 Department of Physics and Astronomy, University of Kentucky, 600 Rose Street, Lexington, KY 40506-0055, USA e-mail: [email protected] 3 Istituto Nazionale di Astrofisica (INAF) – Istituto di Fisica dello Spazio Interplanetario (IFSI), via del Fosso del Cavaliere, 00133 Rome, Italy e-mail: [email protected] 4 Science & Technology BV, PO 608 2600 AP Delft, The Netherlands e-mail: [email protected] 5 Istituto Nazionale di Astrofisica (INAF) – Istituto di Radioastronomia (IRA) – Stazione Radioastronomica di Medicina, via Fiorentina 3508/B, 40059 Medicina (BO), Italy e-mail: [s.montebugnoli;e.salerno;g.maccaferri]@ira.inaf.it; [email protected] 6 Helsinki University of Technology TKK, Metsähovi Radio Observatory, 02540 Kylmälä, Finland e-mail: [amn;jr;jwagner;gofrito;minttu]@kurp.hut.fi Received 18 October 2008 / Accepted 4 December 2008 ABSTRACT Context. The presence of water has long been seen as a key condition for life in planetary environments. The Cassini spacecraft discovered water vapour in the Saturnian system by detecting absorption of UV emission from a background star. Investigating other possible manifestations of water is essential, one of which, provided physical conditions are suitable, is maser emission. -
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. -
A Deeper Look at the Colors of the Saturnian Irregular Satellites Arxiv
A deeper look at the colors of the Saturnian irregular satellites Tommy Grav Harvard-Smithsonian Center for Astrophysics, MS51, 60 Garden St., Cambridge, MA02138 and Instiute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI86822 [email protected] James Bauer Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Dr., MS183-501, Pasadena, CA91109 [email protected] September 13, 2018 arXiv:astro-ph/0611590v2 8 Mar 2007 Manuscript: 36 pages, with 11 figures and 5 tables. 1 Proposed running head: Colors of Saturnian irregular satellites Corresponding author: Tommy Grav MS51, 60 Garden St. Cambridge, MA02138 USA Phone: (617) 384-7689 Fax: (617) 495-7093 Email: [email protected] 2 Abstract We have performed broadband color photometry of the twelve brightest irregular satellites of Saturn with the goal of understanding their surface composition, as well as their physical relationship. We find that the satellites have a wide variety of different surface colors, from the negative spectral slopes of the two retrograde satellites S IX Phoebe (S0 = −2:5 ± 0:4) and S XXV Mundilfari (S0 = −5:0 ± 1:9) to the fairly red slope of S XXII Ijiraq (S0 = 19:5 ± 0:9). We further find that there exist a correlation between dynamical families and spectral slope, with the prograde clusters, the Gallic and Inuit, showing tight clustering in colors among most of their members. The retrograde objects are dynamically and physically more dispersed, but some internal structure is apparent. Keywords: Irregular satellites; Photometry, Satellites, Surfaces; Saturn, Satellites. 3 1 Introduction The satellites of Saturn can be divided into two distinct groups, the regular and irregular, based on their orbital characteristics. -
Dynamics of Saturn's Small Moons in Coupled First Order Planar Resonances
Dynamics of Saturn's small moons in coupled first order planar resonances Maryame El Moutamid Bruno Sicardy and St´efanRenner LESIA/IMCCE | Paris Observatory 26 juin 2012 Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk Saturn system Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk Very small moons Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk New satellites : Anthe, Methone and Aegaeon (Cooper et al., 2008 ; Hedman et al., 2009, 2010 ; Porco et al., 2005) Very small (0.5 km to 2 km) Vicinity of the Mimas orbit (outside and inside) The aims of the work A better understanding : - of the dynamics of this population of news satellites - of the scenario of capture into mean motion resonances Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk Dynamical structure of the system µ µ´ Mp We consider only : - The resonant terms - The secular terms causing the precessions of the orbit When µ ! 0 ) The symmetry is broken ) different kinds of resonances : - Lindblad Resonance - Corotation Resonance D'Alembert rules : 0 0 c = (m + 1)λ − mλ − $ 0 L = (m + 1)λ − mλ − $ Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk Corotation Resonance - Aegaeon (7/6) : c = 7λMimas − 6λAegaeon − $Mimas - Methone (14/15) : c = 15λMethone − 14λMimas − $Mimas - Anthe (10/11) : c = 11λAnthe − 10λMimas − $Mimas Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk Corotation resonances Mean motion resonance : n1 = m+q n2 m Particular case : Lagrangian Equilibrium Points Maryame El Moutamid ESLAB-2012 | ESA/ESTEC Noordwijk Adam's ring and Galatea Maryame -
Cassini Observations of Saturn's Irregular Moons
EPSC Abstracts Vol. 12, EPSC2018-103-1, 2018 European Planetary Science Congress 2018 EEuropeaPn PlanetarSy Science CCongress c Author(s) 2018 Cassini Observations of Saturn's Irregular Moons Tilmann Denk (1) and Stefano Mottola (2) (1) Freie Universität Berlin, Germany ([email protected]), (2) DLR Berlin, Germany 1. Introduction two prograde irregulars are slower than ~13 h, while the periods of all but two retrogrades are faster than With the ISS-NAC camera of the Cassini spacecraft, ~13 h. The fastest period (Hati) is much slower than we obtained photometric lightcurves of 25 irregular the disruption rotation barrier for asteroids (~2.3 h), moons of Saturn. The goal was to derive basic phys- indicating that Saturn's irregulars may be rubble piles ical properties of these objects (like rotational periods, of rather low densities, possibly as low as of comets. shapes, pole-axis orientations, possible global color variations, ...) and to get hints on their formation and Table: Rotational periods of 25 Saturnian irregulars evolution. Our campaign marks the first utilization of an interplanetary probe for a systematic photometric Moon Approx. size Rotational period survey of irregular moons. name [km] [h] Hati 5 5.45 ± 0.04 The irregular moons are a class of objects that is very Mundilfari 7 6.74 ± 0.08 distinct from the inner moons of Saturn. Not only are Loge 5 6.9 ± 0.1 ? they more numerous (38 versus 24), but also occupy Skoll 5 7.26 ± 0.09 (?) a much larger volume within the Hill sphere of Suttungr 7 7.67 ± 0.02 Saturn. -
Observing the Universe
ObservingObserving thethe UniverseUniverse :: aa TravelTravel ThroughThrough SpaceSpace andand TimeTime Enrico Flamini Agenzia Spaziale Italiana Tokyo 2009 When you rise your head to the night sky, what your eyes are observing may be astonishing. However it is only a small portion of the electromagnetic spectrum of the Universe: the visible . But any electromagnetic signal, indipendently from its frequency, travels at the speed of light. When we observe a star or a galaxy we see the photons produced at the moment of their production, their travel could have been incredibly long: it may be lasted millions or billions of years. Looking at the sky at frequencies much higher then visible, like in the X-ray or gamma-ray energy range, we can observe the so called “violent sky” where extremely energetic fenoena occurs.like Pulsar, quasars, AGN, Supernova CosmicCosmic RaysRays:: messengersmessengers fromfrom thethe extremeextreme universeuniverse We cannot see the deep universe at E > few TeV, since photons are attenuated through →e± on the CMB + IR backgrounds. But using cosmic rays we should be able to ‘see’ up to ~ 6 x 1010 GeV before they get attenuated by other interaction. Sources Sources → Primordial origin Primordial 7 Redshift z = 0 (t = 13.7 Gyr = now ! ) Going to a frequency lower then the visible light, and cooling down the instrument nearby absolute zero, it’s possible to observe signals produced millions or billions of years ago: we may travel near the instant of the formation of our universe: 13.7 By. Redshift z = 1.4 (t = 4.7 Gyr) Credits A. Cimatti Univ. Bologna Redshift z = 5.7 (t = 1 Gyr) Credits A. -
Long-Term Evolution and Stability of Saturnian Small Satellites
MNRAS 000, 1–17 (2016) Preprint 30 August 2021 Compiled using MNRAS LATEX style file v3.0 Long-term Evolution and Stability of Saturnian Small Satellites: Aegaeon, Methone, Anthe, and Pallene. M. A. Mun˜oz-Guti´errez,1⋆ and S. Giuliatti Winter1 1Universidade Estadual Paulista - UNESP, Grupo de Dinˆamica Orbital e Planetologia, Av. Ariberto Pereira da Cunha, 333, Guaratinguet´a-SP, 12516-410, Brazil Accepted XXX. Received YYY; in original form ZZZ ABSTRACT Aegaeon, Methone, Anthe, and Pallene are four Saturnian small moons, discovered by the Cassini spacecraft. Although their orbital characterization has been carried on by a number of authors, their long-term evolution has not been studied in detail so far. In this work, we numerically explore the long-term evolution, up to 105 yr, of the small moons in a system formed by an oblate Saturn and the five largest moons close to the region: Janus, Epimetheus, Mimas, Enceladus, and Tethys. By using frequency analysis we determined the stability of the small moons and characterize, through diffusion maps, the dynamical behavior of a wide region of geometric phase space, a vs e, surrounding them. Those maps could shed light on the possible initial number of small bodies close to Mimas, and help to better understand the dynamical origin of the small satellites. We found that the four small moons are long-term stable and no mark of chaos is found for them. Aegaeon, Methone, and Anthe could remain unaltered for at least ∼ 0.5Myr, given the current configuration of the system. They remain well- trapped in the corotation eccentricity resonances with Mimas in which they currently librate. -
Evection Resonance in Saturn's Coorbital Moons Dr
Evection resonance in Saturn's coorbital moons Dr. Cristian Giuppone1, Lic Ximena Saad Olivera2, Dr. Fernando Roig2 (1) Universidad Nacional de Córdoba, OAC - IATE, Córdoba, Ar (2) Observatorio Nacional, Rio de Janeiro, Brasil OPS III - Diversis Mundi - Santiago - Chile Evection resonance in Saturn's coorbital moons MOTIVATION: recent studies in Jovian planets links the evection resonance and the architecture and evolution of their satellites. Evection resonance in Saturn's coorbital moons MOTIVATION: recent studies in Jovian planets links the evection resonance and the architecture and evolution of their satellites. GOAL: understand the evection resonance in the frame of coorbital motion of Satellites, through numerical evidence of its importance. Evection resonance ● The evection resonance is produced when the orbit pericenter of a satellite (ϖ) precess with the same period that the Sun movement as a perturber (λO) (Brouwer and Clemence, 1961) The evection angle → Ψ=λO – ϖ Satellite Sun Saturn ψ = 0° Evection resonance ● The evection resonance is produced when the orbit pericenter of a satellite (ϖ) precess with the same period that the Sun movement as a perturber (λO) (Brouwer and Clemence, 1961) The evection angle → Ψ=λO – ϖ Satellite Sun Saturn ψ = 0° Evection resonance ● Interior resonance: ● Produced by the oblateness of the planet. ● -3 Located at a ~ 10 RP (a~10 au), and several armonics are present. ● Importance: tides produce outward migration of inner moons. The moons can cross the resonance and may change substantially their orbital elements (e.g. Nesvorny et al 2003, Cuk et al. 2016) Evection resonance ● Interior resonance: ● Produced by the oblateness of the planet. -
An Analytical Model for the Dust Environment Around Saturn's
EPSC Abstracts Vol. 9, EPSC2014-310, 2014 European Planetary Science Congress 2014 EEuropeaPn PlanetarSy Science CCongress c Author(s) 2014 An Analytical Model for the Dust Environment around Saturn’s Moons Pallene, Methone and Anthe Michael Seiler, Martin Seiß, Kai-Lung Sun and Frank Spahn Institute of Physics and Astronomy, University of Potsdam, Germany ([email protected]) Abstract Acknowledgements Since its arrival at Saturn in 2004 the observations This work was supported by the Deutsche Forschungs- by the spacecraft Cassini have revolutionised the gemeinschaft (Sp 384/28-1, Sp 384/21-2) and the understanding of the dynamics in planetary rings. Deutsches Zentrum für Luft- und Raumfahrt (OH By analysing Cassini images, Hedman et al. [1] 0003). detected faint dust along the orbits of Saturn’s tiny moons Methone, Anthe and Pallene. While the ring material around Methone and Anthe appears to be References longitudinally confined to arcs, a continuous ring of material has been observed around the orbit of Pallene [1] Hedman, M. M. et al., "Three tenuous rings/arcs for three tiny moons", Icarus, 199, pp. 378-386, 2009 by the Cassini dust analyzer. The data show, that at least part of the torus lies exterior Pallene’s orbit. [2] Cooper, N. J. et al. "Astrometry and dynamics of Anthe (S/2007 S 4), a new satellite of Saturn", Icarus, 195, pp. Many tiny moons are located between Mimas and 765-777, 2008 Enceladus and are known to be resonantly perturbed [3] Spitale, J. N. et al. "The Orbits of Saturn’s Small Satel- by these [2, 3]. -
Resonant Moons of Neptune
EPSC Abstracts Vol. 13, EPSC-DPS2019-901-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. Resonant moons of Neptune Marina Brozović (1), Mark R. Showalter (2), Robert A. Jacobson (1), Robert S. French (2), Jack L. Lissauer (3), Imke de Pater (4) (1) Jet Propulsion Laboratory, California Institute of Technology, California, USA, (2) SETI Institute, California, USA, (3) NASA Ames Research Center, California, USA, (4) University of California Berkeley, California, USA Abstract We used integrated orbits to fit astrometric data of the 2. Methods regular moons of Neptune. We found a 73:69 inclination resonance between Naiad and Thalassa, the 2.1 Observations two innermost moons. Their resonant argument librates around 180° with an average amplitude of The astrometric data cover the period from 1981-2016, ~66° and a period of ~1.9 years. This is the first fourth- with the most significant amount of data originating order resonance discovered between the moons of the from the Voyager 2 spacecraft and HST. Voyager 2 outer planets. The resonance enabled an estimate of imaged all regular satellites except Hippocamp the GMs for Naiad and Thalassa, GMN= between 1989 June 7 and 1989 August 24. The follow- 3 -2 3 0.0080±0.0043 km s and GMT=0.0236±0.0064 km up observations originated from several Earth-based s-2. More high-precision astrometry of Naiad and telescopes, but the majority were still obtained by HST. Thalassa will help better constrain their masses. The [4] published the latest set of the HST astrometry GMs of Despina, Galatea, and Larissa are more including the discovery and follow up observations of difficult to measure because they are not in any direct Hippocamp. -
NWC SAF Convective Precipitation Product from MSG: a New Day-Time Method Based on Cloud Top Physical Properties
Tethys 2015, 12, 3–11 www.tethys.cat ISSN-1697-1523 eISSN-1139-3394 DOI:10.3369/tethys.2015.12.01 Journal edited by ACAM NWC SAF convective precipitation product from MSG: A new day-time method based on cloud top physical properties C. Marcos1, J. M. Sancho2 and F. J. Tapiador3 1Spanish Meteorological Agency (AEMET); Leonardo Prieto Castro, 8, 28071, Madrid 2Spanish Meteorological Agency (AEMET), Territorial delegation in Andalusia, Ceuta and Melilla; Demstenes, 4, 29010 Malaga 3Instituto de Ciencias Ambientales, University of Castilla-La Mancha; Avda. Carlos III s/n, 45071, Toledo Received: 3-XII-2014 – Accepted: 25-III-2015 – Original version Correspondence to: [email protected] Abstract Several precipitation products use radiances and reflectances obtained from the Spinning En- hanced Visible and Infrared Imager (SEVIRI) to estimate convective precipitation. The direct use of these physical quantities in precipitation algorithms is known to generate an overestimation of the precipitation area and an underestimation of the rainfall rates. In order to extenuate these issues, the most recent Satellite Application Facility on Support to Nowcasting & Very Short Range Forecasting (NWC SAF/MSG) software package (version 2013) includes a new day-time algorithm that takes advantage of advances in cloud microphysics estimation, namely a better knowledge of Effective Radius (Reff ), Cloud Optical Thickness (COT) and Water Phase. The improved algorithm, known as Convective Rainfall Rate from Cloud Physical Properties (CRPh), uses such Cloud Top Physical Properties (CPP) to estimate rainfall rates from convective clouds on a SEVIRI pixel basis (about 3 km at nadir). This paper presents the novelties of the new algorithm and provides both a comparison of the product with the previous versions in the NWC SAF/MSG software package, and a validation with independent ground radar data from the Spanish Radar Network operated by AEMET. -
Moons of Saturn
National Aeronautics and Space Administration 0 300,000,000 900,000,000 1,500,000,000 2,100,000,000 2,700,000,000 3,300,000,000 3,900,000,000 4,500,000,000 5,100,000,000 5,700,000,000 kilometers Moons of Saturn www.nasa.gov Saturn, the sixth planet from the Sun, is home to a vast array • Phoebe orbits the planet in a direction opposite that of Saturn’s • Fastest Orbit Pan of intriguing and unique satellites — 53 plus 9 awaiting official larger moons, as do several of the recently discovered moons. Pan’s Orbit Around Saturn 13.8 hours confirmation. Christiaan Huygens discovered the first known • Mimas has an enormous crater on one side, the result of an • Number of Moons Discovered by Voyager 3 moon of Saturn. The year was 1655 and the moon is Titan. impact that nearly split the moon apart. (Atlas, Prometheus, and Pandora) Jean-Dominique Cassini made the next four discoveries: Iapetus (1671), Rhea (1672), Dione (1684), and Tethys (1684). Mimas and • Enceladus displays evidence of active ice volcanism: Cassini • Number of Moons Discovered by Cassini 6 Enceladus were both discovered by William Herschel in 1789. observed warm fractures where evaporating ice evidently es- (Methone, Pallene, Polydeuces, Daphnis, Anthe, and Aegaeon) The next two discoveries came at intervals of 50 or more years capes and forms a huge cloud of water vapor over the south — Hyperion (1848) and Phoebe (1898). pole. ABOUT THE IMAGES As telescopic resolving power improved, Saturn’s family of • Hyperion has an odd flattened shape and rotates chaotically, 1 2 3 1 Cassini’s visual known moons grew.