DOCSLIB.ORG

Jjmonl 1805.Pmd

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Jjmonl 1805.Pmd alactic Observer John J. McCarthy Observatory G Volume 11, No. 5 May 2018 As its fire burns and Cauldron Bubbles, Kilauea’s Secrets are revealed from space Probes the Depths Details on page 16 The John J. McCarthy Observatory Galactic Observer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Production & Design Phone/Fax: (860) 354-1595 www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky Technical Support It is through their efforts that the McCarthy Observatory Bob Lambert has established itself as a significant educational and recreational resource within the western Connecticut Dr. Parker Moreland community. Steve Barone Jim Johnstone Colin Campbell Carly KleinStern Dennis Cartolano Bob Lambert Route Mike Chiarella Roger Moore Jeff Chodak Parker Moreland, PhD Bill Cloutier Allan Ostergren Doug Delisle Marc Polansky Cecilia Detrich Joe Privitera Dirk Feather Monty Robson Randy Fender Don Ross Louise Gagnon Gene Schilling John Gebauer Katie Shusdock Elaine Green Paul Woodell Tina Hartzell Amy Ziffer In This Issue "OUT THE WINDOW ON YOUR LEFT" ............................... 4 ASTRONOMICAL AND HISTORICAL EVENTS ......................... 12 MONS RÜMKER ............................................................. 4 COMMONLY USED TERMS ............................................... 15 JUPITER AT OPPOSITION ................................................... 5 REFERENCES ON DISTANCES ............................................ 15 INSIGHT ........................................................................ 5 INTERNATIONAL SPACE STATION AND IRIDIUM SATELLITES .... 16 BY JOVE, IT'S STORMY .................................................... 6 SOLAR ACTIVITY ........................................................... 16 NEW THEORY FOR MOON FORMATION .............................. 7 LAGRANGE POINTS ........................................................ 16 BREAKING UP IS NOT SO HARD TO DO .............................. 7 IMAGE CREDITS ............................................................ 16 PHILATELY ..................................................................... 8 FRONT PAGE GRAPHICS ................................................. 16 DUST IN THE WIND ......................................................... 8 CONTACT INFORMATION ................................................. 18 PSYCHE SESSION ............................................................. 9 SECOND SATURDAY STARS ............................................... 19 PUBLIC ASTRONOMY ...................................................... 10 APRIL GRAPHIC CALENDAR ............................................ 20 MAY SHOWERS ............................................................. 10 FORGOTTEN NAMES FOR AN ANCIENT WORLD ................... 11 MAY HISTORY ............................................................... 11 JOVIAN MOON TRANSITS ................................................ 12 RED SPOT TRANSITS ...................................................... 12 SUNRISE AND SUNSET ...................................................... 12 MAY NIGHTS .............................................................. 112 May Astronomy Calendar and Space Exploration Almanac InSight, Engineering Test Model Photo: Bill Cloutier "Out the Window on Your Left" T'S BEEN MORE than 45 years Isince we left the last footprint on the dusty lunar surface. Sadly, as a nation founded on exploration and the conquest of new frontiers, we appear to have lost our will to lead North - South profile of Mons Rümker Credit: LROC Quickmap Mons Rümker as a space-faring nation. But, what if the average citizen had the means to visit our only natural satellite; what would they see out the window of their spacecraft as they entered orbit around the Moon? This column may provide some thoughts to pon- der when planning your visit (if only in your imagination). With the intensity of the re- flected sunlight from a nearly full Moon, features on the western rim are often overlooked. However, this area of Oceanus Procellarum ("Ocean of Storms") has an intrigu- ing and varied topography, with impact and volcanic features, including domes, lava channels and subsurface cavities, as well as the most prominent and brightest lunar swirl, Reiner Gamma. Located in the northwest region of Oceanus Procellarum, due west of Mairan Crater and north of the Aristarchus plateau and Marius Hills, is the volcanic feature, Mons Rümker. The elevated complex, rising 2,200 to 3,700 feet (700 to ing plain, is approximately 40 miles (65 km) in diameter and populated 1,100 meters) above the surround- by multiple domes and vents (approximately 30 separate and irregularly 4 • May 2018 JJMO http://www.mccarthyobservatory.org shaped volcanic domes have been rise with the setting Sun and be vis- orbital resonance with the inner identified) and overlapping lava ible all night, appearing highest in three Galilean moons. flows. the south just after midnight. Jupi- Ganymede is Jupiter's largest The region has a very complex ter will remain in the evening sky moon, with a diameter greater than geology, with ancient mare basalts until November when it disappears the planet Mercury. Callisto has the as old as 3.47 billion years adja- into the evening twilight and passes oldest and most heavily cratered cent to much younger basalts, and behind the Sun. Superior conjunc- surface, while Io has one of the basalts with both high iron/tita- tion (when the Sun is directly be- youngest. Io is also the most vol- nium and low iron/titanium con- tween the Earth and Jupiter) occurs canically active world in the solar tent in as many as six distinctly dif- on November 26th. system. ferent geologic units. Spectral Jupiter can be found in the con- Three of the four Galilean analysis of the region indicates stellation Libra (located between moons (excluding Io) may have that the areas adjacent to Mons the bright stars Antares in the con- subsurface oceans. Europa will be Rümker could be as youthful as stellation Scorpius to the east and the target of several future mis- 1.33 billion years, significantly Spica in the constellation Virgo to sions, including ESA's Jupiter Icy younger than lunar samples re- the west). At magnitude -2.3, it will moons Explorer and NASA's turned by the six Apollo missions be one of the brightest, star-like Europa Clipper. which ranged 3 to 4 billion years objects in the night sky (except for Since Europa is embedded in in age. Venus). On May 9th, the gas giant Jupiter's magnetosphere, the Europa China's Lunar Exploration Pro- will be 409 million miles (658 mil- Clipper will spend a majority of its gram has identified Mons Rümker lion km or 4.40 AU) from Earth or time outside the high radiation re- as one of the candidate landing 37 light minutes. The planet's south gions, diving in for brief flybys of sites for its Chang'e-5 sample re- pole will be slightly tipped towards the icy moon. If the mission in- turn mission, currently scheduled Earth (3.3°). cludes a lander, the orbiter could for launch in 2019. The proposed Jupiter reaches Opposition ev- park the lander in a safe, low ra- lander would collect up to 2 kilo- ery 399 days (on average), about a diation orbit until a suitable land- grams of rock, which would then month later each successive year. ing area on Europa can be identi- be transferred to an orbiter by an It is one of the only planets that dis- fied or the lander could follow the ascent module before being re- plays surface (atmospheric) details orbiter in a separate launch. turned to Earth (reminiscent of the through a moderately sized tele- Apollo landing/ orbital rendez- scope. With its rapid rotation (ap- InSight vous sequence). proximately one complete revolu- NASA's Discovery Program tion every 10 hours), the planet's mission InSight (Interior Explora- Jupiter at Opposition cloud belts and storms provide the tion using Seismic Investigations, The Earth comes between the observer with a dynamic spectacle. Geodesy and Heat Transport) is Sun and Jupiter in its orbit on May Jupiter's four Galilean moons scheduled to launch on May 5th 9th (an arrangement known as (discovered by Galileo in 1610) from the Vandenberg Air Force "Opposition" with Jupiter opposite appear as stars along the planet's Base in California aboard a United the Sun in the sky, as viewed from equatorial plane. Their orbital mo- Launch Alliance Atlas V rocket. It Earth). On that day, Jupiter will tion is discernable over the course will be the agency's first interplan- of a single night. The three inner etary mission launched from the moons, Io (1.77 day orbital period), west coast. InSight is currently Europa (3.55 day orbital period) scheduled to land on Mars' Elysium and Ganymede (7.2 day orbital pe- Planitia, a relatively smooth plain riod), are tidally locked with one in Mars' northern hemisphere, and hemisphere always facing Jupiter. named after a mythical paradise of In their synchronistic orbits, Io the afterlife, on November 26th. completes four orbits and Europa The InSight lander is built on a two orbits in the time Ganymede platform similar to that used for the completes one orbit. Furthest from successful Phoenix mission that Jupiter, Callisto, the fourth Galilean explored the planet's polar region, moon, is tidally locked but not in saving testing time and develop- http://www.mccarthyobservatory.org JJMO May 2018 • 5 ment cost. The lander is equipped with two science instruments,
Load more

Recommended publications
  • Surface Characteristics of Transneptunian Objects and Centaurs from Photometry and Spectroscopy
    Barucci et al.: Surface Characteristics of TNOs and Centaurs 647 Surface Characteristics of Transneptunian Objects and Centaurs from Photometry and Spectroscopy M. A. Barucci and A. Doressoundiram Observatoire de Paris D. P. Cruikshank NASA Ames Research Center The external region of the solar system contains a vast population of small icy bodies, be- lieved to be remnants from the accretion of the planets. The transneptunian objects (TNOs) and Centaurs (located between Jupiter and Neptune) are probably made of the most primitive and thermally unprocessed materials of the known solar system. Although the study of these objects has rapidly evolved in the past few years, especially from dynamical and theoretical points of view, studies of the physical and chemical properties of the TNO population are still limited by the faintness of these objects. The basic properties of these objects, including infor- mation on their dimensions and rotation periods, are presented, with emphasis on their diver- sity and the possible characteristics of their surfaces. 1. INTRODUCTION cally with even the largest telescopes. The physical char- acteristics of Centaurs and TNOs are still in a rather early Transneptunian objects (TNOs), also known as Kuiper stage of investigation. Advances in instrumentation on tele- belt objects (KBOs) and Edgeworth-Kuiper belt objects scopes of 6- to 10-m aperture have enabled spectroscopic (EKBOs), are presumed to be remnants of the solar nebula studies of an increasing number of these objects, and signifi- that have survived over the age of the solar system. The cant progress is slowly being made. connection of the short-period comets (P < 200 yr) of low We describe here photometric and spectroscopic studies orbital inclination and the transneptunian population of pri- of TNOs and the emerging results.
    [Show full text]
  • Taxonomy of Trans-Neptunian Objects and Centaurs As Seen from Spectroscopy? F
    A&A 604, A86 (2017) Astronomy DOI: 10.1051/0004-6361/201730933 & c ESO 2017 Astrophysics Taxonomy of trans-Neptunian objects and Centaurs as seen from spectroscopy? F. Merlin1, T. Hromakina2, D. Perna1, M. J. Hong1, and A. Alvarez-Candal3 1 LESIA – Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, France e-mail: [email protected] 2 Institute of Astronomy, Kharkiv V. N. Karin National University, Sumska Str. 35, 61022 Kharkiv, Ukraine 3 Observatorio Nacional, R. Gal. Jose Cristino 77, 20921-400 Rio de Janeiro, Brazil Received 4 April 2017 / Accepted 19 May 2017 ABSTRACT Context. Taxonomy of trans-Neptunian objects (TNOs) and Centaurs has been made in previous works using broadband filters in the visible and near infrared ranges. This initial investigation led to the establishment of four groups with the aim to provide the mean colors of the different classes with possible links with any physical or chemical properties. However, this taxonomy was only made with the Johnson-Cousins filter system and the ESO J, H, Ks filters combination, and any association with other filter system is not yet available. Aims. We aim to edit complete visible to near infrared taxonomy and extend this work to any possible filters system. To do this, we generate mean spectra for each individual group, from a data set of 43 spectra. This work also presents new spectra of the TNO (38628) Huya, on which aqueous alteration has been suspected, and the Centaur 2007 VH305.
    [Show full text]
  • Colours of Minor Bodies in the Outer Solar System II - a Statistical Analysis, Revisited
    Astronomy & Astrophysics manuscript no. MBOSS2 c ESO 2012 April 26, 2012 Colours of Minor Bodies in the Outer Solar System II - A Statistical Analysis, Revisited O. R. Hainaut1, H. Boehnhardt2, and S. Protopapa3 1 European Southern Observatory (ESO), Karl Schwarzschild Straße, 85 748 Garching bei M¨unchen, Germany e-mail: [email protected] 2 Max-Planck-Institut f¨ur Sonnensystemforschung, Max-Planck Straße 2, 37 191 Katlenburg- Lindau, Germany 3 Department of Astronomy, University of Maryland, College Park, MD 20 742-2421, USA Received —; accepted — ABSTRACT We present an update of the visible and near-infrared colour database of Minor Bodies in the outer Solar System (MBOSSes), now including over 2000 measurement epochs of 555 objects, extracted from 100 articles. The list is fairly complete as of December 2011. The database is now large enough that dataset with a high dispersion can be safely identified and rejected from the analysis. The method used is safe for individual outliers. Most of the rejected papers were from the early days of MBOSS photometry. The individual measurements were combined so not to include possible rotational artefacts. The spectral gradient over the visible range is derived from the colours, as well as the R absolute magnitude M(1, 1). The average colours, absolute magnitude, spectral gradient are listed for each object, as well as their physico-dynamical classes using a classification adapted from Gladman et al., 2008. Colour-colour diagrams, histograms and various other plots are presented to illustrate and in- vestigate class characteristics and trends with other parameters, whose significance are evaluated using standard statistical tests.
    [Show full text]
  • KBO Light Curve Paper-For-Public
    A Statistical Review of Light Curves and the Prevalence of Contact Binaries in the Kuiper Belt Mark R. Showaltera*, Susan D. Benecchib, Marc W. Buiec, William M. Grundyd, James T. Keanee, Carey M. Lissef, Cathy B. Olkinc, Simon B. Porterc, Stuart J. Robbinsc, Kelsi N. Singerc, Anne J. Verbiscerg, Harold A. Weaverf, Amanda M. Zangaric, Douglas P. Hamiltonh, David E. Kaufmannc, Tod R. Laueri, D. S. Mehokef, T. S. Mehokef, J. R. Spencerc, H. B. Throopb, J. W. Parkerc, S. Alan Sternc, and the New Horizons Geology, Geophysics, and Imaging Team. a SETI Institute, Mountain View, 189 Bernardo Ave., CA 94043, USA. b Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719, USA. c Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA. d Lowell Observatory, 1400 W. Mars Hill Rd., Flagstaff, AZ 86001, USA. e California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA. f Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd., Laurel, MD 20723, USA. g Department of Astronomy, University of Virginia, 530 McCormick Rd., Charlottesville, VA 22904, USA. h Department of Astronomy, University of Maryland, College Park, MD 20742, USA. i National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719, USA. *Correspondence: [email protected] 1 Abstract We investigate what can be learned about a population of distant Kuiper Belt Objects (KBOs) by studying the statistical properties of their light curves. Whereas others have successfully inferred the properties of individual, highly variable KBOs, we show that the fraction of KBOs with low amplitudes also provides fundamental information about a population.
    [Show full text]
  • Transneptunian Object Taxonomy 181
    Fulchignoni et al.: Transneptunian Object Taxonomy 181 Transneptunian Object Taxonomy Marcello Fulchignoni LESIA, Observatoire de Paris Irina Belskaya Kharkiv National University Maria Antonietta Barucci LESIA, Observatoire de Paris Maria Cristina De Sanctis IASF-INAF, Rome Alain Doressoundiram LESIA, Observatoire de Paris A taxonomic scheme based on multivariate statistics is proposed to distinguish groups of TNOs having the same behavior concerning their BVRIJ colors. As in the case of asteroids, the broadband spectrophotometry provides a first hint about the bulk compositional properties of the TNOs’ surfaces. Principal components (PC) analysis shows that most of the TNOs’ color variability can be accounted for by a single component (i.e., a linear combination of the col- ors): All the studied objects are distributed along a quasicontinuous trend spanning from “gray” (neutral color with respect to those of the Sun) to very “red” (showing a spectacular increase in the reflectance of the I and J bands). A finer structure is superimposed to this trend and four homogeneous “compositional” classes emerge clearly, and independently from the PC analy- sis, if the TNO sample is analyzed with a grouping technique (the G-mode statistics). The first class (designed as BB) contains the objects that are neutral in color with respect to the Sun, while the RR class contains the very red ones. Two intermediate classes are separated by the G mode: the BR and the IR, which are clearly distinguished by the reflectance relative increases in the R and I bands. Some characteristics of the classes are deduced that extend to all the objects of a given class the properties that are common to those members of the class for which more detailed data are available (observed activity, full spectra, albedo).
    [Show full text]
  • Physical Properties of Transneptunian Objects 879
    Cruikshank et al.: Physical Properties of Transneptunian Objects 879 Physical Properties of Transneptunian Objects D. P. Cruikshank NASA Ames Research Center M. A. Barucci Observatoire de Paris, Meudon J. P. Emery SETI Institute and NASA Ames Research Center Y. R. Fernández University of Central Florida W. M. Grundy Lowell Observatory K. S. Noll Space Telescope Science Institute J. A. Stansberry University of Arizona In 1992, the first body beyond Neptune since the discovery of Pluto in 1930 was found. Since then, nearly a thousand solid bodies, including some of planetary size, have been dis- covered in the outer solar system, largely beyond Neptune. Observational studies of an expanding number of these objects with space- and groundbased telescopes are revealing an unexpected diversity in their physical characteristics. Their colors range from neutral to very red, revealing diversity in their intrinsic surface compositions and/or different degrees of processing that they have endured. While some show no diagnostic spectral bands, others have surface deposits of ices of H2O, CH4, and N2, sharing these properties with Pluto and Triton. Thermal emission spectra of some suggest the presence of silicate minerals. Measurements of thermal emission allow determinations of the dimensions and surface albedos of the larger (diameter > ~75 km) members of the known population; geometric albedos range widely from 2.5% to >60%. Some 22 transneptunian objects (including Pluto) are multiple systems. Pluto has three satellites, while 21 other bodies, representing about 11% of the sample investigated, are binary systems. In one binary system where both the mass and radius are reliably known, the mean density of the pri- mary is ~500 kg/m3, comparable to some comets [e.g., Comet 1P/Halley (Keller et al., 2004)].
    [Show full text]
  • Physical Properties of Kuiper Belt and Centaur Objects: Constraints from the Spitzer Space Telescope
    Stansberry et al.: Physical Properties 161 Physical Properties of Kuiper Belt and Centaur Objects: Constraints from the Spitzer Space Telescope John Stansberry University of Arizona Will Grundy Lowell Observatory Mike Brown California Institute of Technology Dale Cruikshank NASA Ames Research Center John Spencer Southwest Research Institute David Trilling University of Arizona Jean-Luc Margot Cornell University Detecting heat from minor planets in the outer solar system is challenging, yet it is the most efficient means for constraining the albedos and sizes of Kuiper belt objects (KBOs) and their progeny, the Centaur objects. These physical parameters are critical, e.g., for interpreting spec- troscopic data, deriving densities from the masses of binary systems, and predicting occultation tracks. Here we summarize Spitzer Space Telescope observations of 47 KBOs and Centaurs at wavelengths near 24 and 70 µm. We interpret the measurements using a variation of the stan- dard thermal model (STM) to derive the physical properties (albedo and diameter) of the targets. We also summarize the results of other efforts to measure the albedos and sizes of KBOs and Centaurs. The three or four largest KBOs appear to constitute a distinct class in terms of their albedos. From our Spitzer results, we find that the geometric albedo of KBOs and Centaurs is correlated with perihelion distance (darker objects having smaller perihelia), and that the albe- dos of KBOs (but not Centaurs) are correlated with size (larger KBOs having higher albedos). We also find hints that albedo may be correlated with visible color (for Centaurs). Interest- ingly, if the color correlation is real, redder Centaurs appear to have higher albedos.
    [Show full text]
  • Composition of Icy Bodies in the Outer Solar System Through the Eyes of IRTF: Current and Future
    Composition of icy bodies in the outer solar system through the eyes of IRTF: current and future S. Protopapa (University of Maryland, SwRI) NASA IRTF FUTURE DIRECTIONS WORKSHOP, 12-14 FEBRUARY 2018 Scientific interests Objects of Study Methodology Trans-Neptunian Goal objects (TNOs) COMPOSITION ANALYSIS Comets formation and •ground and space evolution of the solar system based observations •modeling efforts Asteroids •laboratory studies The Moon Future directions •low resolution visible spectrometer (0.3-0.7 !m) •Adaptive optics •Implement Spextool to reduce data taken with the 60”-slit •IRTF facility in the south •low resolution prism extending up to 4.2 !m (R~200) Pluto versus Triton Grundy et al. 2013 IRTF/SpeX Pluto short cross-dispersed mode CO N2 H2O H2O CO CO2 Grundy et al. 2010 IRTF/SpeX Triton B V R IRTF/SpeX PRISM 0.7-2.52 !m Pluto versus Triton Grundy et al. 2013 IRTF/SpeX Pluto CO ? N2 H2O H2O CO CO2 Grundy et al. 2010 IRTF/SpeX Triton B V R VIS IRTF/SpeX PRISM 0.7-2.52 !m Tholin-like material (Matarese et al. 2015, Cruikshank et al. 2016) laboratory data tholin-like materials Reflectance spectrum of Pluto’s ice tholin obtained in the laboratory. The steep rise in reflectance in the range from~400nm to 1000nm demonstrates the red-orange color of the material Tholin-like material (Matarese et al. 2015, Cruikshank et al. 2016) laboratory data tholin-like materials Lorenzi et al. 2016 ground-based data Tholin-like material (Matarese et al. 2015, Cruikshank et al. 2016) laboratory data tholin-like materials Lorenzi et al.
    [Show full text]
  • Opposition Optical Phenomena in Planetary Astrophysics: Observational Results
    Opposition optical phenomena in planetary astrophysics: observational results Vera K. Rosenbush1* and Michael I. Mishchenko2 1 Main Astronomical Observatory of the National Academy of Sciences of Ukraine, 27 Akademika Zabolotnoho St., 03680 Kyiv, Ukraine 2 NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA Abstract. The photometric phenomenon in the form of a nonlinear increase of brightness at small phase angles and a negative branch of polarization are typical of the majority of Solar System bodies. In addition, some high-albedo objects re- veal a backscattering polarization feature in the form of a spike-like negative- polarization minimum called the polarization opposition effect. These optical phe- nomena are important tests of our theoretical descriptions of light scattering by re- golith planetary surfaces. In this chapter we review the recent progress in the study of optical opposition phenomena in planetary astrophysics. We primarily focus on the results of polarimetric observations of asteroids, the Galilean satellites of Jupi- ter, the Saturnian satellite Iapetus, Centaurs, and trans-Neptunian objects at back- scattering geometries including phase angles approaching zero. Keywords: polarimetry, opposition effects, asteroids, satellites, Centaurs, trans-Neptunian objects 1. Introduction Polarimetry and photometry are especially sensitive diagnostic tools helping to infer the physical properties of bodies whose observational characteristics are governed by small scatterers, e.g., dust and regolith grains. It is these methods that have provided convincing indications of the presence of regolith on planetary sur- faces long before the advent of space missions. Measurements of the intensity and polarization of scattered light as functions of the phase angle and wavelength have been used to gain an improved understanding of the microphysical properties of the surfaces of many Solar System bodies.
    [Show full text]
  • Exploring the Composition of Icy Bodies at the Fringes of the Solar System with Next Generation Space Telescopes
    Exploring the composition of icy bodies at the fringes of the solar system with next generation space telescopes Thematic Areas: ☒ Planetary Systems Principal Author: Name: Richard J. Cartwright Institution: SETI Institute / NASA Ames Research Center Email: [email protected] Co-authors: (names and institutions) Bryan Holler Space Telescope Science Institute Susan Benecchi Planetary Science Institute Roser Juanola-Parramon NASA Goddard Space Flight Center Giada Arney NASA Goddard Space Flight Center Aki Roberge NASA Goddard Space Flight Center Heidi Hammel Association of Universities for Research in Astronomy Co-signers: Tracy Becker, Chloe Beddingfield, Dale Cruikshank, Katherine de Kleer, Paul Estrada, Amanda Hendrix, Jason Hofgartner, Stefanie Milam, Marc Neveu, Tom Nordheim, Andy Rivkin, Megan Schwamb, Francesca Scipioni, Linda Spilker, Matthew Tiscareno, David Trilling, Anne Verbiscer, Michael Wong 1. Abstract and Motivation Determining the distribution and spectral signature of volatile ices and organics exposed on icy body surfaces can provide crucial clues for deciphering how the outer solar system formed and evolved (e.g., [1, 2]). Icy objects with primordial surfaces retain valuable information about the state and variety of constituents present in the early solar system. Icy objects with more processed surfaces demonstrate how the original mixture of constituents has evolved through time. Over the past few decades, ground- and space-based telescope observations have probed the compositions of a wide range of icy objects with primordial or processed surfaces, revealing the presence of numerous volatile ices and organic residues (e.g., [3]). Although these telescope observations have advanced our understanding of icy bodies beyond Saturn, the sensitivity and spatial resolution of collected datasets are limited by the large heliocentric distances of these far-flung objects.
    [Show full text]
  • Absolute Magnitudes and Phase Coefficients of Trans-Neptunian Objects
    A&A 586, A155 (2016) Astronomy DOI: 10.1051/0004-6361/201527161 & c ESO 2016 Astrophysics Absolute magnitudes and phase coefficients of trans-Neptunian objects A. Alvarez-Candal1, N. Pinilla-Alonso2, J. L. Ortiz3,R.Duffard3, N. Morales3, P. Santos-Sanz3, A. Thirouin4, and J. S. Silva1 1 Observatório Nacional / MCTI, Rua General José Cristino 77, 20921-400 Rio de Janeiro, RJ, Brazil e-mail: [email protected] 2 Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, 37996, USA 3 Instituto de Astrofísica de Andalucía, CSIC, Apt 3004, 18080 Granada, Spain 4 Lowell Observatory, 1400 W Mars Hill Rd, Flagstaff, 86001 Arizona, USA Received 10 August 2015 / Accepted 27 November 2015 ABSTRACT Context. Accurate measurements of diameters of trans-Neptunian objects (TNOs) are extremely difficult to obtain. Thermal modeling can provide good results, but accurate absolute magnitudes are needed to constrain the thermal models and derive diameters and geometric albedos. The absolute magnitude, HV , is defined as the magnitude of the object reduced to unit helio- and geocentric distances and a zero solar phase angle and is determined using phase curves. Phase coefficients can also be obtained from phase curves. These are related to surface properties, but only few are known. Aims. Our objective is to measure accurate V-band absolute magnitudes and phase coefficients for a sample of TNOs, many of which have been observed and modeled within the program “TNOs are cool”, which is one of the Herschel Space Observatory key projects. Methods. We observed 56 objects using the V and R filters. These data, along with those available in the literature, were used to obtain phase curves and measure V-band absolute magnitudes and phase coefficients by assuming a linear trend of the phase curves and considering a magnitude variability that is due to the rotational light-curve.
    [Show full text]
  • Formation of Trans-Neptunian Satellite Systems at the Stage of Condensations
    Formation of Trans-Neptunian Satellite Systems at the Stage of Condensations S. I. Ipatova, b aVernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academу of Sciences, Moscow, Russia bSpace Research Institute, Russian Academy of Sciences, Moscow, Russia e-mail: [email protected] Received April 19, 2016 Abstract⎯The formation of trans-Neptunian satellite systems at the stage of rarefied preplanetesimals (i.e., condensations of dust and/or objects less than 1 m in diameter) is discussed. It is assumed that trans-Neptunian objects (including those with satellites) could form as a result of compression of parental rarefied pre-planetesimals. The formulas for calculating the angular momentum of two colliding condensations with respect to their center of mass, which were applied earlier in (Ipatov, 2010) in the comparison of such momenta with the angular momenta of observed satellite systems, are used to estimate the angular momenta of condensations needed to form satellite systems. It is demonstrated that the angular velocities of condensations used in (Nesvorny et al., 2010) as the initial data in the computer simulation of compression of rarefied preplanetesimals and subsequent formation of trans-Neptunian satellite systems may be obtained in collisions of preplanetesimals with their radii comparable to the corresponding Hill radii. For example, these angular velocities are in the range of possible values of angular velocities of a parental rarefied preplanetesimal formed as a result of a merger of two colliding rarefied preplanetesimals that moved in circular heliocentric orbits before a collision. Some rarefied preplanetesimals formed as a result of collision of preplanetesimals in the region of formation of solid small bodies acquire such angular momenta that are sufficient to form satellite systems of small bodies.
    [Show full text]