相关论文: The composition of Mars
Mercury's high uncompressed mass density suggests that the planet is largely composed of iron, either bound within metal (mainly Fe-Ni), or iron sulfide. Recent results from the MESSENGER mission to Mercury imply a low temperature history…
The origin of Phobos and Deimos in a giant impact generated disk is gaining larger attention. Although this scenario has been the subject of many studies, an evaluation of the chemical composition of the Mars' moons in this framework is…
Despite its importance to questions of lunar origin, the chemical composition of the Moon is not precisely known. In recent years, however, the isotopic composition of lunar samples has been determined to high precision and found to be…
We report Keck/HIRES and HST/COS spectroscopic studies of extrasolar rocky planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD 133. In G29-38, 8 elements are detected, including C, O, Mg, Si, Ca, Ti, Cr and Fe…
The intense debate about the presence of methane in the Martian atmosphere has stimulated the study of methanogens adapted to terrestrial habitats that mimic Martian environments. We examinate the environmental conditions, energy sources…
One of the outstanding goals of the planetary science community is to measure the present-day atmospheric composition of planets and link this back to formation. As giant planets are formed by accreting gas, ices, and rocks, constraining…
The composition of the lower mantle $-$ comprising 56% of Earth's volume $-$ remains poorly constrained. Among the major elements, Mg/Si ratios ranging from $\sim$0.9$-$1.1, such as in rocky solar-system building blocks (or chondrites), to…
From core to atmosphere, the oxidation states of elements in a planet shape its character. Oxygen fugacity (fO$_2$) is one parameter indicating these likely oxidation states. The ongoing search for atmospheres on rocky exoplanets benefits…
Evidence is now compelling that most externally-polluted white dwarfs derive their heavy atoms by accretion from asteroids - the building blocks of rocky planets. Optical and ultraviolet spectroscopy of a small sample of suitable white…
Although deuterium (D) on Mars has received substantial attention, the deuterated ionosphere remains relatively unstudied. This means that we also know very little about non-thermal D escape from Mars, since it is primarily driven by excess…
The Martian upper atmosphere is known to vary diurnally and seasonally due to changing amounts of solar radiation. However, in the upper thermosphere and exosphere, the neutrals are also subject to ion precipitation. This can increase the…
The evidence for abundant liquid water on early Mars despite the faint young Sun is a long-standing problem in planetary research. Here we present new ab initio spectroscopic and line-by-line climate calculations of the warming potential of…
We use the Mars Regional Atmospheric Modeling System (MRAMS) to simulate lake storms on Mars, finding that intense localized precipitation will occur for lake size >=10^3 km^2. Mars has a low-density atmosphere, so deep convection can be…
Refractory elements such as iron, magnesium, and silicon can be detected in the atmospheres of ultrahot giant planets. This provides an opportunity to quantify the amount of refractory material accreted during formation, along with volatile…
Regolith on Mars exchanges water with the atmosphere on a diurnal basis and this process causes significant variation in the abundance of water vapor at the surface. While previous studies of regolith-atmosphere exchange focus on the…
Post-Noachian Martian paleochannels indicate the existence of liquid water on the surface of Mars after about 3.5 Gya (Irwin et al., 2015; Palucis et al., 2016). In order to explore the effects of variations in CO$_{2}$ partial pressure and…
Conventional planet formation theory suggests that chondritic materials have delivered crucial atmospheric and hydrospheric elements such as carbon (C), nitrogen (N), and hydrogen (H) onto primitive Earth. However, recent measurements…
Using high-quality spectra of the twin stars in the XO-2 binary system, we have detected significant differences in the chemical composition of their photospheres. The differences correlate strongly with the elements' dust condensation…
The knowledge of isotopic and elemental abundances of the pristine solar system material provides a fundamental test of galactic chemical evolution models, while the composition of the solar photosphere is a reference pattern to understand…
Carbonaceous chondrite meteorites are known for having high water and organic material contents, including amino acids. Here we address the origin of amino acids in the warm interiors of their parent bodies (planetesimals) within a few…