2,975 research outputs found
Variations in solar wind fractionation as seen by ACE/SWICS over a solar cycle and the implications for Genesis Mission results
We use ACE/SWICS elemental composition data to compare the variations in
solar wind fractionation as measured by SWICS during the last solar maximum
(1999-2001), the solar minimum (2006-2009) and the period in which the Genesis
spacecraft was collecting solar wind (late 2001 - early 2004). We differentiate
our analysis in terms of solar wind regimes (i.e. originating from interstream
or coronal hole flows, or coronal mass ejecta). Abundances are normalized to
the low-FIP ion magnesium to uncover correlations that are not apparent when
normalizing to high-FIP ions. We find that relative to magnesium, the other
low-FIP elements are measurably fractionated, but the degree of fractionation
does not vary significantly over the solar cycle. For the high-FIP ions,
variation in fractionation over the solar cycle is significant: greatest for
Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance
ratios are examined as a function of solar wind speed, we find a strong
correlation, with the remarkable observation that the degree of fractionation
follows a mass-dependent trend. We discuss the implications for correcting the
Genesis sample return results to photospheric abundances.Comment: Accepted for publication in Ap
Characterisation of Float Rocks at Ireson Hill, Gale Crater
Float rocks discovered by surface missions on Mars have given unique insights into the sedimentary, diagenetic and igneous processes that have operated throughout the planets history. In addition, Gale sedimentary rocks, both float and in situ, record a combination of source compositions and diagenetic overprints. We examine a group of float rocks that were identified by the Mars Science Laboratory missions Curiosity rover at the Ireson Hill site, circa. sol 1600 using ChemCam LIBS, APXS and images from the MastCam, Mars Hand Lens Imager (MAHLI) and ChemCam Remote Micro-Imager (RMI) cameras. Geochemical data provided by the APXS and ChemCam instruments allow us to compare the compositions of these rocks to known rock types from Gale crater, as well as elsewhere on Mars. Ireson Hill is a 15 m long butte in the Murray formation with a dark cap-ping unit with chemical and stratigraphic consistency with the Stimson formation. A total of 6 float rocks have been studied on the butte
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In Search of the Solar Wind Nitrogen Isotope Composition: Analysis of a Gold Plate from the Genesis Spacecraft Concentrator
We report N isotope analysis of a gold plate from the Genesis spacecraft concentrator. We did not find evidence for a light N component in the solar wind
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Curie: Constraining Solar System Bombardment Using In Situ Radiometric Dating
The Curie mission would constrain the existence of the putative cataclysm by determining the age of samples directly sourced from the impact melt sheet of a major pre-Imbrium lunar basin. The measurements would also enable further understanding of lunar evolution by characterizing new lunar lithologies far from the Apollo and Luna landing sites, including the very low-Ti basalts in Mare Crisium and potential olivine rich lithologies in the margins of both Mare Nectaris and Mars Crisium. Equipped with a mass spectrometer and a LIBS, Curie would also be well-placed to survey volatile components of the lunar regolith, including surface-bound hydrogen
Concepts of visual consciousness and their measurement.
Although visual consciousness can be manipulated easily (e.g., by visual
masking), it is unresolved whether it can be assessed accurately with behavioral
measures such as discrimination ability and self-report. Older theories of
visual consciousness postulated a sensory threshold and distinguished between
subjective and objective thresholds. In contrast, newer theories distinguish
among three aspects: phenomenal, access, and reflexive consciousness. This
review shows that discrimination ability and self-report differ in their
sensitivity to these aspects. Therefore, both need to be assessed in the study
of visual consciousness
Postcards from Mars: Insights into Martian Geochemical Processes from the Curiosity Rover
With the successful landing of the Mars Curiosity Rover
in August 2012, we now have the most capable geochemical
laboratory ever to travel to another planet roving Mars’ Gale
crater. The geochemical instrument suite includes the
Chemistry Camera (ChemCam), which uses a laser to vaporize
geologic targets and performs atomic emission spectroscopy
on the vapor from distances of up to 7m. This provides a
geochemical surveying capability that enables rapid
identification of unique specimens and accumulation of a large
set of rock and fines compositions as the rover traverses. The
Alpha Particle X-ray Spectrometer (APXS) provides high
quality “bulk” elemental analyses for major, minor and a few
trace elements through a touch deployment on the surface of a
rock or soil, and is an upgraded version of similar instruments
previously flown to Mars. The addition of x-ray diffraction
through the Chemistry and Mineralogy (CheMin) instrument
and volatile, isotope, and organic analyses with the Sample
Analysis at Mars (SAM) instrument suite, give Curiosity the
capability to assess the geochemical history of the planet more
deeply than previously possible.
Both CheMin and SAM accept sieved fines from either
Curiosity’s scoop or drill. To date, sampling has occurred at
the Rocknest aeolian drift deposit and a fine-grained mudstone
called John Klein. At Rocknest, CheMin found a mix of
primary igneous minerals and amorphous materials. SAM
found that Rocknest fines contain significant bound volatiles
that can be released upon heating, largely associated with the
amorphous material. Because APXS and ChemCam data
support the fines being representative of those found at other
sites on Mars, Curiosity results show that martian fines are a
good source of water, CO2 and other volatiles that could be
leveraged by living organisms, including future human
explorers. At John Klein, early results are consistent with an
ancient aqueous habitable environment. Analyses of isotopes
and organics also provide exciting windows into martian
habitability and volatile evolution. These early geochemical
results will be discussed
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Fluorine in the Pahrump outcrop, Gale Crater: Implications for fluid circulation and alteration
Broadband seismic deployments in East Antarctica: IPY contribution to understand the Gamburtsev Province -AGAP/GAMSEIS– \n
第30回極域地学シンポジウム「極域から探る固体地球ダイナミクス」12月3日(金) 国語研究所 2階講
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