Results 111 to 120 of about 16,638 (219)

The role of composition in the spectral evolution of carbonaceous asteroids as informed by Bennu sample return

Meteoritics &Planetary Science, EarlyView.
Abstract Near‐Earth rubble‐pile asteroids Bennu and Ryugu are part of the carbonaceous taxonomic complex (C‐complex), and samples returned from both bodies resemble the most aqueously altered carbonaceous chondrites. However, telescopic and spacecraft visible–near infrared (VIS–NIR) reflectance spectra of Ryugu exhibit a red (positive) spectral slope ...
Ralph E. Milliken, Takahiro Hiroi, Victoria E. Hamilton, Cody D. Schultz, Ed A. Cloutis, Hannah H. Kaplan, Melissa K. Kontogiannis, Nathalia Vega‐Santiago, Dani N. DellaGiustina, Harold C. Connolly Jr., Dante S. Lauretta   +10 more
wiley   +1 more source

Role of Polycyclic Aromatic Hydrocarbons with Edge Defects in Explaining Astronomical Infrared Emission Observations

The Astrophysical Journal
A systematic study was performed on the spectral properties of polycyclic aromatic hydrocarbons (PAHs) with edge defects using harmonic density functional theory calculations.
A. Ricca, J. E. Roser, C. Boersma, E. Peeters, A. Maragkoudakis   +4 more
doaj   +1 more source

Evaluating maturity of organic matter in hydrated C1 and CM‐like clasts and a dehydrated clast within a polymict eucrite and a howardite

Meteoritics &Planetary Science, EarlyView.
Abstract Volatile‐rich xenolithic clasts in different types of brecciated meteorites represent unique pristine solar system material. This study investigates the maturity and thermal history of organic matter using Raman spectroscopy and aqueous alteration effects using infrared spectroscopy in the matrix of 15 volatile‐rich clasts (C1 and CM‐like ...
Swarna Prava Das, Alessandro Maturilli, Aurélie Van den Neucker, Markus Patzek, Dipak Kumar Panda, Gopal K. Pradhan, Guneshwar Thangjam, Surya Snata Rout   +7 more
wiley   +1 more source

Raman analysis of organic refractory materials after energetic processing: Evidence for amorphous carbon on TNOs and comets

Meteoritics &Planetary Science, EarlyView.
Abstract Amorphous carbon (αC) is found in various extraterrestrial particles, including those thought to originate from the outer Solar System. αC can form through two main processes involving C‐rich materials: exposure to energetic charged particles and thermal processing.
M. Germanà, A. Vyjidak, G. A. Baratta, B. M. Giuliano, R. G. Urso, C. Scirè, D. Fulvio, T. Grassi, P. Jusko, P. Caselli, M. E. Palumbo   +10 more
wiley   +1 more source

Origin and formation of a chondritic xenolith in Krymka (LL3.2, breccia): Indications for a late formation of the accretionary breccia

Meteoritics &Planetary Science, EarlyView.
Abstract An unusual chondritic xenolith was found in two sequentially prepared thin sections of a sample from the Krymka (LL3.2) chondrite. The xenolith has a rounded, slightly deformed shape of about 5 mm in apparent diameter and is partially surrounded by a double rim made of an inner fine‐grained silicate‐rich rim and an outer sulfide‐rich rim.
Aelita Girich, Addi Bischoff, Samuel Ebert, Kazuhide Nagashima, Andreas Morlok, Harald Hiesinger, Jasper Berndt   +6 more
wiley   +1 more source

A Simple Model of the Radio–Infrared Correlation Depending on Gas Surface Density and Redshift

The Astrophysical Journal
We introduce a simple parametric model of the radio–infrared correlation (i.e., the ratio between the IR luminosity and the 1.4 GHz radio luminosity, q _IR ) by considering the energy loss rate of high-energy cosmic-ray (CR) electrons governed by ...
Ilsang Yoon
doaj   +1 more source

Nanoscale space weathering features in mature lunar soil revealed by TEM and APT

Meteoritics &Planetary Science, EarlyView.
Abstract Space weathering significantly alters the optical, chemical, and structural properties of lunar regolith at micro‐ and nanoscales; yet detailed nanoscale variability within individual soils remains underexplored. Here we apply transmission electron microscopy (TEM) and atom probe tomography to four mineral grains (olivine, ilmenite, and two ...
Jennika Greer, Alexander M. Kling, Luke Daly, Dieter Isheim, David N. Seidman, Michelle S. Thompson, Philipp R. Heck   +6 more
wiley   +1 more source

HgCdTe Apd Arrays for Astronomy: Natural Guide Star Wavefront Sensing and Space Astronomy. [PDF]

, 2018
This dissertation describes work I have conducted over ve academic years 2013/14 through 2017/18 as a NASA Space Technology Research Fellow at the University of Hawai'i Institute for Astronomy.
Atkinson, Dani E.
core  

Potassium isotopic compositions and exposure ages of evolved and silica‐rich achondrites

Meteoritics &Planetary Science, EarlyView.
Abstract Some of the oldest igneous rocks in the Solar System include evolved and silica‐rich achondrites that originate from parent bodies less than 1000 km in diameter, referred to as planetesimals. While Earth was initially in a molten state and required continental crust formation and plate tectonics to generate andesite bulk compositions, evolved ...
Z. Vaci, Z. Tian, P. Koefoed, M. Habermann, M. Humayun, K. Ziegler, H. Busemann, D. Krietsch, J. M. D. Day, K. Wang   +9 more
wiley   +1 more source

Uncovering the impact of the cardiovascular system on cerebrovascular health using MRI

Experimental Physiology, EarlyView.
Abstract Human cerebrovasculature is finely tuned to enable local changes in blood flow to meet the brain's demands, whilst protecting the brain from systemic changes in blood pressure, both acutely during a heartbeat and chronically over time. This review summarises cerebrovascular structure and function, their role in disease and neurodegeneration ...
Ian D. Driver, Kevin Murphy
wiley   +1 more source