Showing papers in "Icarus in 2018"

TL;DR: In this article, the authors used observations of the Mars upper atmosphere made from the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft to determine the loss rates of gas from the upper atmosphere to space for a complete Mars year (16 Nov 2014 − 3 Oct 2016).

TL;DR: In this article, the authors revisited the work of Morbidelli et al. that examined which scenario could be compatible with both the lunar crater record in the 3-4-Gy period and the abundance of highly siderophile elements (HSE) in the lunar mantle.

TL;DR: In this article, the authors presented a new four-dimensional model of the near-Earth objects population that describes debiased steady-state distributions of semimajor axis, eccentricity, inclination, and absolute magnitude H in the range 17.962 − 56 + 52 + 52 ( 802 − 42 + 48 × 10 3 ) NEOs with H.

TL;DR: In this article, the authors used 800 dynamical simulations to show that an early instability in the outer solar system strongly influences terrestrial planet formation and regularly yields properly sized Mars analogs, and their most successful outcomes occur when the terrestrial planets evolve an additional 1-10 million years following the dispersal of the gas disk, before the onset of the giant planet instability.

TL;DR: In this paper, the authors studied the water vapor vertical distribution in the middle atmosphere of Mars during the 2007 global dust storm based on solar occultation measurements by the SPICAM IR spectrometer onboard the Mars-Express spacecraft.

TL;DR: The Alice instrument on NASA's New Horizons spacecraft observed an ultraviolet solar occultation by Pluto's atmosphere on 2015 July 14, and derived line-of-sight abundances and local number densities for the 5 molecular species, and line of-sight optical depth and extinction coefficients for the haze.

TL;DR: In this paper, Gault et al. presented a model that describes a mixing front that proceeds downward from the surface following a power-law function of time and showed that secondary impacts are necessary to produce the reworking rate inferred from the depth distribution of surface correlated material in Apollo cores.

TL;DR: In the case of Pluto and Charon, the most distant objects so mapped, a unique feature of the Pluto imaging data set is the observation of terrains illuminated only by light scattered from atmospheric haze, allowing us to map terrains in the southern hemisphere that would otherwise have been in darkness.

TL;DR: In this article, a detailed description of the seasonal and spatial distribution of CO in the Mars atmosphere and new information about the interannual variability of H2O was provided by radiative transfer modeling of near-infrared spectra taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument onboard MRO.

TL;DR: This article examined the geometry and architecture of the Jezero western delta fluvial stratigraphy using high-resolution orbital images and digital elevation models (DEMs) to reconstruct the evolution of the delta and associated shoreline position.

TL;DR: More than a third of all exoplanets can be classified as super-Earths based on radius (1−2 R⊕) and mass (1 −2 R ) as mentioned in this paper.

TL;DR: In this paper, the authors examine the prospect of forming chondrules from impact splashes among planetesimals heated by radioactive decay of short-lived radionuclides using thermomechanical models of their interior evolution.

TL;DR: In this article, the mineralogy of the whole crater is analyzed in this work, and the spectral parameters of all main absorption bands, photometry, and continuum slope are analyzed using the VIR instrument on board the Dawn spacecraft.

TL;DR: A map of the near subsurface hydrogen distribution on Mars, based on epithermal neutron data from the Mars Odyssey Neutron Spectrometer, is presented in this article.

TL;DR: In this paper, the authors re-compute heliocentric orbits for the 25 meteorite falls published to date from original data sources and constrain their most likely escape routes from the main asteroid belt and the cometary region by utilizing a state-of-the-art orbit model of the near-Earth-object population, which includes a size-dependence in delivery efficiency.

TL;DR: In this paper, the authors present concordance estimates of the elemental abundances of the bulk Earth, which can be used to calibrate the unresolved discrepancies between standard Earth models under various geochemical and geophysical assumptions.

TL;DR: GEM-Mars as mentioned in this paper is a gridpoint-based three-dimensional general circulation model of the Mars atmosphere extending from the surface to approximately 150 km based on the GEM (Global Environmental Multiscale) model, part of the operational weather forecasting and data assimilation system for Canada.

TL;DR: This article performed a comprehensive analysis of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral dataset using factor analysis and target transformation methods to efficiently parse through the large quantity of data.

TL;DR: In this article, the authors present numerical simulations of volatile transport on Pluto performed with a model designed to simulate the nitrogen cycle over millions of years, taking into account the changes of obliquity, solar longitude of perihelion and eccentricity as experienced by Pluto.

TL;DR: Ceres' gravity field and rotational parameters have been precisely measured using 1.5 years of radiometric Doppler and range data and optical landmark tracking from the Dawn spacecraft in orbit about the dwarf planet as mentioned in this paper.

TL;DR: In this article, the authors investigated the temperature and compressional stress dependence of the thermal conductivity of the lunar regolith simulant JSC-1A, and the temperature dependence of sieved JSC1A samples under vacuum conditions.

TL;DR: In this paper, the authors explore how a steady supply of atmospheric haze might affect three distinct provinces on Pluto, and they pose the question of why they each look so different from one another if the same haze material is settling out onto all of them.

TL;DR: In this article, the authors analyzed the Dawn Framing Camera's images and characterized the surfaces as composed of a central structure, either a possible depression (Vinalia) or a central dome (Cerealia), and a discontinuous mantling.

TL;DR: In this article, the authors performed a pixel-by-pixel analysis of Nix's disk-resolved spectra and found that the surface is consistent with a uniform crystalline H2O-ice fraction, and a ǫ∼ 50% variation in the normalized band area of the 2.21µm band with a minimum associated with the red blotch seen in color images.

TL;DR: In this paper, the results of initial inflight calibration based on observations of Earth, Mars, Moon, and stars to verify and characterize the optical performance of the ONC, such as flat-field sensitivity, spectral sensitivity, point-spread function (PSF), distortion, and stray light of ONC-W1 and W2, were evaluated.

TL;DR: In this paper, the authors analyzed the thermal infrared data acquired by the NASA's Wide-field Infrared Survey Explorer of about 300 asteroids with derived convex shape models and derived thermophysical modeling.

TL;DR: In this article, the results of lab experiments in which materials with porosity ranging from 43% to 96% were impacted at ∼1800m/s were performed on a geotechnical centrifuge, in order to reproduce the lithostatic overburden stress and ejecta ballistics that occur in large-scale cratering events on asteroids or planetary satellites.

TL;DR: In this paper, the history of the loss and replenishment of the Martian atmosphere using elemental and isotopic compositions of nitrogen and noble gases was examined by taking into consideration various processes, such as impact erosion, replenishment by asteroids and comets, atmospheric escape induced by solar radiation and wind, volcanic degassing, and gas deposition by interplanetary dust particles.

TL;DR: In this paper, the authors identified and mapped 129 mare basalt deposits in and around the South Pole-Aitken (SPA) basin, and determined absolute model ages (AMAs) for 101 of these units by performing crater size-frequency distribution (CSFD) measurements.

TL;DR: In the case of Venus, several GCMs succeeded in reproducing the atmosphere's superrotation and the global temperature field as discussed by the authors, but the highly variable polar temperature and the permanent cold collar present at latitude have not been reproduced satisfactorily yet.