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All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Mount Etna as A Terrestrial Laboratory to Investigate Recent Volcanic Activity on Venus By Future Missions: A Comparison With Idunn Mons, Venus

The recently selected missions to Venus have opened a new era for the exploration of this planet. These missions will provide information about the chemistry of the atmosphere, the geomorphology, local-to-regional surface composition, and the rheology of the interior. One key scientific question to be addressed by these future missions is whether Venus remains volcanically active, and if so, how its volcanism is currently evolving. Hence, it is fundamental to analyze appropriate terrestrial analog sites for the study of possibly active volcanism on Venus. To this regard, we propose Mount Etna - one of the most active and monitored volcanoes on Earth - as a suitable terrestrial laboratory for remote and in-situ investigations to be performed by future missions to Venus. Being characterized by both effusive and explosive volcanic products, Mount Etna offers the opportunity to analyze multiple eruptive styles, both monitoring active volcanism and identifying the possible occurrence of pyroclastic activity on Venus. We directly compare Mount Etna with Idunn Mons, one of the most promising potentially active volcanoes of Venus. Despite the two structures show a different topography, they also show some interesting points of comparison, and in particular: a) comparable morpho-structural setting, since both volcanoes interact with a rift zone, and b) morphologically similar volcanic fields around both Mount Etna and Idunn Mons. Given its ease of access, we also propose Mount Etna as an analog site for laboratory spectroscopic studies to identify the signatures of unaltered volcanic deposits on Venus.

P D DIncecco↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mo3+ is bonded to four equivalent N3- atoms to form corner-sharing MoN4 tetrahedra. All Mo–N bond lengths are 2.02 Å. N3- is bonded to four equivalent Mo3+ atoms to form corner-sharing NMo4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Mo3+ is bonded in a body-centered cubic geometry to eight equivalent N3- atoms. All Mo–N bond lengths are 2.34 Å. N3- is bonded in a body-centered cubic geometry to eight equivalent Mo3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN is Tungsten Carbide structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Mo3+ is bonded to six equivalent N3- atoms to form a mixture of distorted corner, edge, and face-sharing MoN6 pentagonal pyramids. All Mo–N bond lengths are 2.19 Å. N3- is bonded to six equivalent Mo3+ atoms to form a mixture of distorted corner, edge, and face-sharing NMo6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mo3+ is bonded to six equivalent N3- atoms to form a mixture of edge and corner-sharing MoN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mo–N bond lengths are 2.18 Å. N3- is bonded to six equivalent Mo3+ atoms to form a mixture of edge and corner-sharing NMo6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Mo3+ is bonded in a rectangular see-saw-like geometry to four equivalent N3- atoms. There are one shorter (2.00 Å) and three longer (2.06 Å) Mo–N bond lengths. N3- is bonded in a distorted rectangular see-saw-like geometry to four equivalent Mo3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Mo3+ sites. In the first Mo3+ site, Mo3+ is bonded in a 4-coordinate geometry to four N3- atoms. There are two shorter (2.06 Å) and two longer (2.07 Å) Mo–N bond lengths. In the second Mo3+ site, Mo3+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Mo–N bond distances ranging from 2.01–2.49 Å. In the third Mo3+ site, Mo3+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Mo–N bond distances ranging from 2.13–2.28 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 6-coordinate geometry to six Mo3+ atoms. In the second N3- site, N3- is bonded in a 5-coordinate geometry to five Mo3+ atoms. In the third N3- site, N3- is bonded to four Mo3+ atoms to form distorted edge-sharing NMo4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Mo3+ is bonded to six equivalent N3- atoms to form a mixture of edge, face, and corner-sharing MoN6 octahedra. The corner-sharing octahedral tilt angles are 45°. All Mo–N bond lengths are 2.19 Å. N3- is bonded to six equivalent Mo3+ atoms to form a mixture of distorted edge and corner-sharing NMo6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoN by Materials Project

MoN is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Mo3+ sites. In the first Mo3+ site, Mo3+ is bonded to six equivalent N3- atoms to form a mixture of distorted corner, edge, and face-sharing MoN6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 44°. All Mo–N bond lengths are 2.16 Å. In the second Mo3+ site, Mo3+ is bonded to six equivalent N3- atoms to form a mixture of corner, edge, and face-sharing MoN6 octahedra. All Mo–N bond lengths are 2.22 Å. N3- is bonded to six Mo3+ atoms to form a mixture of distorted corner, edge, and face-sharing NMo6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
NASA NTRS2016

Geologic Mapping of Ascraeus Mons, Mars

Ascraeus Mons (AM) is the northeastern most large shield volcano residing in the Tharsis province on Mars. We are funded by NASA's Mars Data Analysis Program to complete a digital geologic map based on the mapping style. Previous mapping of a limited area of these volcanoes using HRSC images (13-25 m/pixel) revealed a diverse distribution of volcanic landforms within the calderas, along the flanks, rift aprons, and surrounding plains. The general scientific objectives for which this mapping is based is to show the different lava flow morphologies across AM to better understand the evolution and geologic history.

Volcanoes↗
NASA NTRSDate not supplied

Idunn Mons as the landing site of the Venera-D mission: scientific relevance and possible operational tests on Mount Etna.

Along with the recently selected NASA DAVINCI [1] and VERITAS [2] missions, and with the ESA EnVision mission [3], the Roscosmos Venera-D mission [4,5] opens the new decade of Venus exploration. Among these missions, the Venera-D is the only one to be equipped with a lander which could drill the surface of Venus and analyze its chemical composition. For this reason, it is crucial to select a future landing site based on its scientific relevance, as well as on safety constraints. We propose here Idunn Mons (Figure 1a), a major large volcano of Imdr Regio, as the landing site for the Venera-D mission. We also indicate Mount Etna in Italy (Figure 1b) as a suitable test site on Earth for drilling tests and in-situ elemental and mineralogical analyses [6,7].

venus↗
DOE OSTI2025

Steam-Assisted Ammonolysis of MoO2 as a Synthetic Pathway to Oxygenated δ-MoN

A common route for the synthesis of molybdenum nitrides is through the temperature-programmed reaction of molybdenum oxides with NH3, or ammonolysis. In this work, the role of precursor phase, gas phase chemistry (impact of H2O), and temperature profile on the reaction outcome (700 °C) was examined, which resulted in varying amounts of MoO2, H2MoO5, and the nitride phases—cubic γ (nominally Mo2N) and hexagonal δ (nominally MoN). The phase fraction of the δ phase increased with precursor in the sequence MoO2 > MoO3 > H2MoO5. Steam in the reaction gas also favored the production of δ over γ, but with too much steam, MoO2 was obtained in the product. Synthesis conditions for obtaining nearly phase-pure δ were identified: MoO2 as the precursor, 2% H2O in the gas stream, and a moderate heating rate (3 °C/min). In situ X-ray diffraction provided insights into the reaction pathway. Extensive physico-chemical analysis of the δ phase, including synchrotron X-ray and neutron diffraction, electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and prompt gamma activation analysis, revealed its stoichiometry to be MoO0.108(8)N0.892(8)H0.012(5), indicating non-trivial oxygen incorporation. The presence of N/O ordering and an impurity phase Mo5N6 were also revealed, detectable only by neutron diffraction. Notably, a computationally predicted MoON phase (doi: 10.1103/PhysRevLett.123.236402), of interest due to its potential to display a metal-insulator transition, did not appear under any reaction condition examined.

Pandey, Shobhit↗
NASA NTRS1974

Variable features on Mars. IV - Pavonis Mons

A remarkable set of albedo changes has been uncovered by Mariner 9 photography of the upper slopes of the shield volcano Pavonis Mons, near its summit caldera. The most likely explanation of the event is aeolian transport of fine-grained particles. Since the atmospheric pressure in this locality is about 1.5 mb, minimum wind velocities above the surface boundary layer of about 110 m per sec are necessary, corresponding to 0.51 of the speed of sound. Slope winds in this velocity range are expected near the upper flanks of major Martian volcanic constructs.

Sagan, C.↗
NASA NTRS1981

Notes on the early-type components of W Cep, o Cet, CH Cyg, AR Mon, and BL Tel

Low resolution IUE spectra in both spectral regions are used to clarify the nature of the warmer components of several binary systems. The W Cep, the primary of which is a luminous K-type supergiant, shows an ultraviolet absorption spectrum of type B0 or B1; this system is heavily reddened. The hot companion of Mira (o Cet) is surprisingly faint in the short wavelength region, but it excites a rich emission spectrum from the surrounding gas. The ultraviolet active M7 giant CH Cyg is shown to be a binary with a hot companion. This system was also observed at high resolution and shows variable Fe II emission and well-separated circumstellar and interstellar absorptions within the broad Mg II emission profiles. The eclipsing binaries AR Mon and BL Tel are shown not to have hot companions.

Wing, R. F.↗
NASA NTRS1982

IUE spectroscopy, visible-band polarimetry, and radiometry of V641 Mon

This hot, double line, ellipsoidal variable member of NGC 2264 has been shown previously to be either a semi-detached or contact close binary. Low-resolution IUE spectra are best fitted to a Kurucz model atmosphere for very small (approximately 0.08 mag) E(B-V). The familiar interstellar absorption dip near lambda 2200 is apparently absent. A suitable model atmosphere can be fitted to the IUE fluxes, but flux excesses (compared to the model) appear for all the published U through L magnitudes. The spectrum of the B through L excess appears to follow a .0001 lambda dependence. It is shown that this cannot be interpreted as arising from another star fortuitously observed in the visible band or IR. Ground based polarization measures indicate V641 Mon to be a polarization variable. Previous and new V light curves show the amplitude of light variability itself to be variable by about a factor of 2. It is suggested that all these observed characteristics are best explained by postulating "third light" and identifying part of it with Rayleigh scattered starlight very near to the stars. From this same region there arise circumstellar absorptions which give rise to nontheoretical strengths for Si II and Si III lines.

Koch, R. H.↗
NASA NTRS1985

Estimates of rheologic properties for flows on the Martian volcano Ascraeus Mons

Morphological measurements on six well-defined volcanic flows near the summit of the Martian volcano Ascraeus Mons were used to calculate the yield strength and viscosity of the lavas. The results are similar to values obtained for flows on other Martian and terrestrial shield volcanoes. Calculated viscosities are generally higher than measured viscosities for basaltic lavas but considerably smaller than rhyolite or dacite viscosities. The estimated rheologic properties of the Martian flows are most consistent with basaltic or basaltic andesite lavas, but some individual flows could consist of more evolved lavas.

Zimbelman, J. R.↗
NASA NTRS1986

A study of the dust distribution and extinction law in Mon R2

Observations were obtained at wavelengths from 1.5 to 7.5 microns with beams varying in diameter from 4 to 28 arcsec of infrared hydrogen recombination lines toward the Mon R2 IRS1 H II region. It is found that the data cannot be fitted with the extinction law which characterizes the interstellar medium unless the obscuring matter is clumped on a small scale of not greater than 0.3 arcsec; in which case considerable fluctuations in the amount of extinction on scales smaller than 1 arcsec are expected. The data of Simon et al. (1983) suggest a dip in the extinction about 5 arcsec from the 2-micron and radio continuum peak, and rule out models with uniform dust and clump distributions.

Natta, A.↗
NASA NTRS1990

Evolution of the Olympus Mons Caldera, Mars

Extensive high-resolution (15 to 20 m/pixel) coverage of Olympus Mons volcano permits the investigation of the sequence of events associated with the evolution of the nested summit caldera. The sequence of the intra-caldera events is well illustrated by image data collected on orbits 473S and 474S of Viking Orbiter 1. These data cover both the oldest and youngest portions of the caldera floor. The chronology inferred from the observations is presented which in turn can be interpreted in terms of the internal structure of the volcano (i.e., magma chamber depth and the existence of dikes).

Mouginis-Mark, Peter J.↗