The NASA Lucy Mission: Surveying the Diversity of Trojan Asteroids

2020 ◽  
Author(s):  
Simone Marchi ◽  
Hal Levison ◽  
Cathy Olkin ◽  
Keith Noll
Keyword(s):  
Solar System ◽  
Infrared Imaging ◽  
Surface Composition ◽  
Equal Mass ◽  
Rotational Axis ◽  
Trojan Asteroids ◽  
Imaging Spectrometer ◽  
Axis Orientation ◽  
Lagrange Points ◽  
Wide Range

<p class="western" align="justify"><span>The Lucy Mission is a NASA Discovery class mission to send a highly capable and robust spacecraft to investigate </span><span>seven</span><span> Jupiter Trojan asteroids; a class of stable, primitive bodies near both the L4 and L5 Lagrange points with Jupiter. It is believed that Jupiter Trojan asteroids are leftover planetesimals from the outer planetary system that have been preserved since early in Solar System history, and represent the last of all of the stable populations of the Solar System to be visited by spacecraft. </span></p> <p class="western" align="justify"><span> Lucy is slated to launch in October 2021, reach its first Trojan asteroid in 2027, and have its final encounter in 2033. During its lifetime, Lucy will perform five Trojan encounters closely studying at least seven objects (one encounter is of a nearly equal mass binary and another is an asteroid with a known satellite). The science goals include determining the surface composition, assessing the geology, determining the bulk properties and searching for satellites around all of Lucy’s targets. The payload suite consists of a color camera and infrared imaging spectrometer, a high resolution panchromatic imager, and a thermal infrared spectrometer. Additionally, two spacecraft subsystems will also contribute to the science investigations: the terminal tracking cameras and the telecommunication subsystem to measure the mass of the Trojan asteroids.</span></p> <p class="western" align="justify"><span> Lucy’s Trojan targets include one C-type (Eurybates, 64 km in diameter), three P-types (Menoetius, Patroclus, and Polymele; 10</span><span>5</span><span>, 11</span><span>4</span><span>, 21 km in diameter, respectively), and two D-types (Leucus and Orus; </span><span>41</span><span> and 5</span><span>2</span><span> km in diameter, respectively), thereby covering a wide range of spectral types and sizes. Lucy will be the first spacecraft to observe the largest remnant of a catastrophic collision up close (Eurybates), and the first to visit a near-equal mass binary (Patroclus and Menoetius). In addition, on its way to L4, Lucy will fly by DonaldJohanson in 2025, a 4 km in diameter </span><span>Main Belt </span><span>asteroid named in honor of the discoverer of the Lucy fossil. In this talk, recent results from an international observational campaign of some of the Lucy’s targets will be presented, including the detection of a small satellite (1-2 km) orbiting Eurybates, and a detailed characterization of Leucus’s shape and rotational axis orientation.</span></p>

scholarly journals The short life of the volcanic island New Late’iki (Tonga) analyzed by multi-sensor remote sensing data

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Simon Plank ◽  
Francesco Marchese ◽  
Nicola Genzano ◽  
Michael Nolde ◽  
Sandro Martinis
Keyword(s):  
Infrared Imaging ◽  
Rapid Change ◽  
Monitoring Network ◽  
Remote Sensing Data ◽  
Volcanic Island ◽  
Imaging Spectrometer ◽  
Remote Areas ◽  
Moderate Resolution ◽  
Satellite Sensors ◽  
Resolution Imaging

AbstractSatellite-based Earth observation plays a key role for monitoring volcanoes, especially those which are located in remote areas and which very often are not observed by a terrestrial monitoring network. In our study we jointly analyzed data from thermal (Moderate Resolution Imaging Spectrometer MODIS and Visible Infrared Imaging Radiometer Suite VIIRS), optical (Operational Land Imager and Multispectral Instrument) and synthetic aperture radar (SAR) (Sentinel-1 and TerraSAR-X) satellite sensors to investigate the mid-October 2019 surtseyan eruption at Late’iki Volcano, located on the Tonga Volcanic Arc. During the eruption, the remains of an older volcanic island formed in 1995 collapsed and a new volcanic island, called New Late’iki was formed. After the 12 days long lasting eruption, we observed a rapid change of the island’s shape and size, and an erosion of this newly formed volcanic island, which was reclaimed by the ocean two months after the eruption ceased. This fast erosion of New Late’iki Island is in strong contrast to the over 25 years long survival of the volcanic island formed in 1995.

scholarly journals Flux rope axis geometry of magnetic clouds deduced from in situ data

2013 ◽  
Vol 8 (S300) ◽  
pp. 265-268
Author(s):  
Miho Janvier ◽  
Pascal Démoulin ◽  
Sergio Dasso
Keyword(s):  
Interplanetary Medium ◽  
Magnetic Cloud ◽  
Flux Rope ◽  
Magnetic Clouds ◽  
Direct Integration ◽  
Axis Orientation ◽  
In Situ Data ◽  
Geometrical Features ◽  
Wide Range

AbstractMagnetic clouds (MCs) consist of flux ropes that are ejected from the low solar corona during eruptive flares. Following their ejection, they propagate in the interplanetary medium where they can be detected by in situ instruments and heliospheric imagers onboard spacecraft. Although in situ measurements give a wide range of data, these only depict the nature of the MC along the unidirectional trajectory crossing of a spacecraft. As such, direct 3D measurements of MC characteristics are impossible. From a statistical analysis of a wide range of MCs detected at 1 AU by the Wind spacecraft, we propose different methods to deduce the most probable magnetic cloud axis shape. These methods include the comparison of synthetic distributions with observed distributions of the axis orientation, as well as the direct integration of observed probability distribution to deduce the global MC axis shape. The overall shape given by those two methods is then compared with 2D heliospheric images of a propagating MC and we find similar geometrical features.

Improved measurement of Asteroid (4) Vesta’s rotational axis orientation

Icarus ◽  
2011 ◽  
Vol 211 (1) ◽  
pp. 528-534 ◽  
Author(s):  
Jian-Yang Li ◽  
Peter C. Thomas ◽  
Brian Carcich ◽  
Max J. Mutchler ◽  
Lucy A. McFadden ◽  
...  
Keyword(s):  
Rotational Axis ◽  
Axis Orientation

Trans-Neptunian Dwarf Planets

2021 ◽  
Author(s):  
Bryan Holler
Keyword(s):  
Solar System ◽  
Surface Composition ◽  
Planetary Science ◽  
Chemical Diversity ◽  
Asteroid Belt ◽  
Dynamical Structure ◽  
Forthcoming Article ◽  
Cold Temperatures ◽  
Dwarf Planets ◽  
Physical And Chemical

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article. The International Astronomical Union (IAU) officially recognizes five objects as dwarf planets: Ceres in the main asteroid belt between Mars and Jupiter; and Pluto, Eris, Haumea, and Makemake in the trans-Neptunian region beyond the orbit of Neptune. However, the definition used by the IAU applies to many other trans-Neptunian objects (TNOs) and can be summarized as any nonsatellite large enough to be rounded by its own gravity. Practically speaking, this means any nonsatellite with a diameter >400 km. In the trans-Neptunian region, there are more than 100 objects that satisfy this definition, based on published results and diameter estimates. The dynamical structure of the trans-Neptunian region records the migration history of the giant planets in the early days of the solar system. The semi-major axes, eccentricities, and orbital inclinations of TNOs across various dynamical classes provide constraints on different aspects of planetary migration. For many TNOs, the orbital parameters are all that is known about them, due to their large distances, small sizes, and low albedos. The TNO dwarf planets are a different story. These objects are large enough to be studied in more detail from ground- and space-based observatories. Imaging observations can be used to detect satellites and measure surface colors, while spectroscopy can be used to constrain surface composition. In this way, TNO dwarf planets not only help provide context for the dynamical evolution of the outer solar system, but also reveal the composition of the primordial solar nebula as well as the physical and chemical processes at work at very cold temperatures. The largest TNO dwarf planets, those officially recognized by the IAU, plus others such as Sedna, Quaoar, and Gonggong, are large enough to support volatile ices on their surfaces in the present day. These ices are able to exist as solids and gases on some TNOs, due to their sizes and surface temperatures (similar to water ice on Earth) and include N2 (nitrogen), CH4 (methane), and CO (carbon monoxide). A global atmosphere composed of these three species has been detected around Pluto, the largest TNO dwarf planet, with the possibility of local atmospheres or global atmospheres at perihelion for Eris and Makemake. The presence of nonvolatile species, such as H2O (water), NH3 (ammonia), and organics provide valuable information on objects that may be too small to retain volatile ices over the age of the solar system. In particular, large quantities of H2O mixed with NH3 points to ancient cryovolcanism caused by internal differentiation of ice from rock. Organic material, formed through radiation processing of surface ices such as CH4, records the radiation histories of these objects as well as providing clues to their primordial surface compositions. The dynamical, physical, and chemical diversity of the >100 TNO dwarf planets are key to understanding the formation of the solar system and subsequent evolution to its current state. Most of our knowledge comes from a small handful of objects, but we are continually expanding our horizons as additional objects are studied in more detail.

scholarly journals The composition of Europa's near-surface atmosphere

2008 ◽  
Vol 4 (S251) ◽  
pp. 327-328
Author(s):  
Mau C. Wong ◽  
Tim Cassidy ◽  
Robert E. Johnson
Keyword(s):  
Solar System ◽  
Surface Composition ◽  
Near Surface ◽  
Water Ice ◽  
Model Studies ◽  
Surface Atmosphere ◽  
Jovian Magnetosphere ◽  
Ice Surface ◽  
Geophysical Phenomenon ◽  
Inorganic Species

AbstractThe presence of an undersurface ocean renders Europa as one of the few planetary bodies in our Solar System that has been conjectured to have possibly harbored life. Some of the organic and inorganic species present in the ocean underneath are expected to transport upwards through the relatively thin ice crust and manifest themselves as impurities of the water ice surface. For this reason, together with its unique dynamic atmosphere and geological features, Europa has attracted strong scientific interests in past decades.Europa is imbedded inside the Jovian magnetosphere, and, therefore, is constantly subjected to the immerse surrounding radiations, similar to the other three Galilean satellites. The magnetosphere-atmosphere-surface interactions form a complex system that provides a multitude of interesting geophysical phenomenon that is unique in the Solar System. The atmosphere of Europa is thought to have created by, mostly, charged particles sputtering of surface materials. Consequently, the study of Europa's atmosphere can be used as a tool to infer the surface composition. In this paper, we will discuss our recent model studies of Europa's near-surface atmosphere. In particular, the abundances and distributions of the dominant O2 and H2O species, and of other organic and inorganic minor species will be addressed.

scholarly journals Detection and Quantification of Snow Algae with an Airborne Imaging Spectrometer

2001 ◽  
Vol 67 (11) ◽  
pp. 5267-5272 ◽  
Author(s):  
Thomas H. Painter ◽  
Brian Duval ◽  
William H. Thomas ◽  
Maria Mendez ◽  
Sara Heintzelman ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Wavelength Range ◽  
Spectral Reflectance ◽  
Infrared Imaging ◽  
Spectral Signature ◽  
Absorption Feature ◽  
Imaging Spectrometer ◽  
Algal Concentration ◽  
Airborne Imaging ◽  
Spectrometer Data

ABSTRACT We describe spectral reflectance measurements of snow containing the snow alga Chlamydomonas nivalis and a model to retrieve snow algal concentrations from airborne imaging spectrometer data. Because cells of C. nivalis absorb at specific wavelengths in regions indicative of carotenoids (astaxanthin esters, lutein, β-carotene) and chlorophylls a and b, the spectral signature of snow containing C. nivalis is distinct from that of snow without algae. The spectral reflectance of snow containing C. nivalis is separable from that of snow without algae due to carotenoid absorption in the wavelength range from 0.4 to 0.58 μm and chlorophyll a and babsorption in the wavelength range from 0.6 to 0.7 μm. The integral of the scaled chlorophyll a and b absorption feature (I 0.68) varies with algal concentration (Ca ). Using the relationshipCa = 81019.2 I 0.68+ 845.2, we inverted Airborne Visible Infrared Imaging Spectrometer reflectance data collected in the Tioga Pass region of the Sierra Nevada in California to determine algal concentration. For the 5.5-km2 region imaged, the mean algal concentration was 1,306 cells ml−1, the standard deviation was 1,740 cells ml−1, and the coefficient of variation was 1.33. The retrieved spatial distribution was consistent with observations made in the field. From the spatial estimates of algal concentration, we calculated a total imaged algal biomass of 16.55 kg for the 0.495-km2 snow-covered area, which gave an areal biomass concentration of 0.033 g/m2.

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