A radiative transfer model was used to reproduce several millions of OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) spectra representative of igneous terrains of Mars. This task provided the modal composition and grain sizes at a planetary scale. The lithology can be summarized in five mineral maps at km-scale. We found that the low albedo equatorial regions of the Martian surface (from 60°S to 30°N) are globally dominated by plagioclase with average abundance ~50 vol% and pyroxenes with total averaged abundance close to 40 vol%. An evolution of the LCP/(LCP+HCP) ratio is observed with time at the global scale, suggesting an evolution of the degree of partial melting throughout the Martian eras. Olivine and Martian dust are minor components of the modelled terrains. The olivine distribution is quite different from the other minerals because it is found on localized areas with abundance reaching 20 vol%. A statistical approach, to classify the pixels of the abundances maps, using k-means clustering, highlighted seven distinct mineral assemblages on the surface. This classification illustrates that diverse mineralogical units are found in the Noachian and Hesperian terrains, which suggests the presence of various and complex magmatic processes at a global scale during the two oldest eras. The chemical composition was derived from the modal composition maps. The OMEGA-derived chemical composition is quite consistent with several distinctive geochemical characteristics previously considered as fingerprints of the Martian surface. A major discrepancy is in regards to the Fe content that is significantly smaller than soil and rock analyses from GRS and in situ measurements. The discrepancy could be partly explained by the assumptions used for the spectral modelling or could also indicate surface alteration rinds.
The M3 project: 1- A global hyperspectral image-cube of the Martian surface
本文是一系列论文中的第一篇,该系列论文将介绍从欧空局/火星快车上的OMEGA成像光谱仪(Observatoire pour la Minéralogie,l 'Eau,les Glaces et l' Activité)获得的近红外数据集在全球范围内推导火星模式矿物学(M3项目)。其目标是创建并提供一个覆盖火星大部分表面的32 px/°的火星全球三维图像立方体。这个产品有几个优点。首先,它可以用于即时提取火星上任何位置的大气和气溶胶校正的近红外(NIR)光谱。其次,可以构建几个新的数据映射,如这里所讨论的。这包括新的全球矿物分布,定量矿物丰度分布和火星表面化学(氧化物重量%)地图,详见配套文件(Riu等人,提交)。在这里,我们提出的方法来获得全球高光谱立方体从数亿光谱。一些镁铁质矿物的全球地图,然后显示,并与以前的作品。
Surface composition and taxonomic classification of a group of near-Earth and Mars-crossing asteroids
过去,由于缺乏含有矿物学诊断吸收带的高质量近红外光谱数据(0.7-2.5微米),限制近地小行星的表面组成一直很困难。在这里,我们提出了可见光(0.43-0.95微米)和近红外(0.7-2.5微米)光谱的九个近地小行星和五个火星穿越小行星(MC)。所研究的非经济实体是:4055 Magellan,19764(2000 NF 5),89830(2002 CE),138404(2000 HA 24),143381(2003 BC 21),159609(2002 AQ 3),164121(2003 YT 1),241662(2000 KO 44)和2007 ML 13。它们是:1656 Suomi、2577 Litva、5407(1992 AX)、22449 Ottijeff和47035(1998 WS)。这些观测是由智利拉西拉的NTT、西班牙卡拉尔阿尔托的2.2米望远镜和夏威夷莫纳克亚山的IRTF进行的。小行星的分类学分类(Bus系统)表明,所有观测到的MC小行星都属于S-复合体,包括S、Sr和Sl类。其中7个近地小行星属于S复合体,包括S、Sa、Sk和Sl类,2个近地小行星被划为V型。NEA 164121(2003 YT 1)是根据其近红外光谱被分类为V型的,因为这颗小行星没有可见光谱。对其中六颗小行星(已获得或以前可获得近红外光谱的小行星)进行了矿物学分析。我们发现三颗小行星(241…
Direct detection of hydrogen reveals a new macroscopic crustal water reservoir on early Mars
Technical University of Denmark(丹麦技术大学);University of Copenhagen(哥本哈根大学);Paul Scherrer Institut(保罗谢勒研究所);European Synchrotron Radiation Facility(欧洲同步辐射装置)
A Global High-Resolution Hydrological Model to Simulate the Dynamics of Surface Liquid Reservoirs: Application on Mars
Laboratoire de Météorologie Dynamique, CNRS, Sorbonne Université(动力气象实验室,法国国家科学研究中心,索邦大学);Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux(波尔多天体物理实验室,波尔多大学)
MRO/CRISM Retrieval of Surface Lambert Albedos for Multispectral Mapping of Mars with DISORT-based Rad. Transfer Modeling: Phase 1 - Using Historical Climatology for Temperatures, Aerosol Opacities, & Atmo. Pressures
The Goldilocks problem for detecting water in terrestrial planets: Constraining water abundances in the mid-IR with LIFE
University of Edinburgh(爱丁堡大学);York University(约克大学);ETH Zurich(苏黎世联邦理工学院);NASA Goddard Space Flight Center(美国国家航空航天局戈达德太空飞行中心);German Aerospace Center (DLR)(德国航空航天中心(DLR));Free University of Berlin(柏林自由大学);University of Groningen(格罗宁根大学);University of Bern(伯尔尼大学)