Open Access. Powered by Scholars. Published by Universities.®

Physical Processes Commons™

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 4 of 4

Full-Text Articles in Physical Processes

Ratification Of The Base Of The Ics Geological Time Scale: The Global Standard Stratigraphic Age (Gssa) For The Hadean Lower Boundary, Janna Halla, Nora Noffke, Humberto Reis, Stanley Awramik, Andrey Bekker, Alexander Brasier, Flávia Callefo, Adrita Choudhury, Jan-Peter Duda, Christopher Fedo, Douglas Galante, Jessica Haddock, Peter Haines, Linda Hinnov, Axel Hofmann, Martin Homann, David Huston, Simon Johnson, Linda Kah, Martin Whitehouse, Et Al. Jan 2024

Ratification Of The Base Of The Ics Geological Time Scale: The Global Standard Stratigraphic Age (Gssa) For The Hadean Lower Boundary, Janna Halla, Nora Noffke, Humberto Reis, Stanley Awramik, Andrey Bekker, Alexander Brasier, Flávia Callefo, Adrita Choudhury, Jan-Peter Duda, Christopher Fedo, Douglas Galante, Jessica Haddock, Peter Haines, Linda Hinnov, Axel Hofmann, Martin Homann, David Huston, Simon Johnson, Linda Kah, Martin Whitehouse, Et Al.

OES Faculty Publications

The base of the ICS (International Commission on Stratigraphy) Geological Time Scale was ratified in 2022 by defining a new Global Stratigraphic Standard Age (GSSA) for the lower boundary of the Hadean Eon (formerly 4000-3600 Ma); the age of the Solar System based on the oldest solids, calcium-aluminium inclusions (CAIs), generated in the protoplanetary disk. The formal GSSA for the Hadean base is the oldest reliable, weighted mean U-corrected Pb-Pb age of 4567.30 ± 0.16 Ma obtained for CAIs in primitive meteorites Allende and Efremovka. This age is supported by the 4568-4567 Ma U-corrected Pb-Pb ages of chondrules in Northwest …


Fully Relativistic Derivation Of The Thermal Sunyaev-Zel'dovich Effect, Balša Terzić, Geoffrey A. Krafft, William Clark, Alexandre Deur, Emerson Rogers, Ioannis Sakiotis, Brandon Velasco Jan 2024

Fully Relativistic Derivation Of The Thermal Sunyaev-Zel'dovich Effect, Balša Terzić, Geoffrey A. Krafft, William Clark, Alexandre Deur, Emerson Rogers, Ioannis Sakiotis, Brandon Velasco

Physics Faculty Publications

We present the first fully and inherently relativistic derivation of the thermal Sunyaev-Zel'dovich effect. This work uses the formalism historically applied to compute radiation spectra emerging from inverse Thomson/Compton sources of x-ray radiation. Comparing our results to the traditional approach based on relativistically-corrected classical Kompaneets equation, we find small, but systematic differences. Most notable are the modest (⩽10%) differences in the crossover frequency where the spectral distortion due to the Sunyaev-Zel'dovich effect vanishes, and the quadratic scaling of the energy shift with the electron cloud temperatures.


Infrared Spectra Of Small Radicals For Exoplanetary Spectroscopy: Oh, Nh, Cn, And Ch: The State Of Current Knowledge, Svatopluk Civiš, Adam Pastorek, Martin Ferus, Sergei N. Yurchenko, Noor-Ines Boudjema Jan 2023

Infrared Spectra Of Small Radicals For Exoplanetary Spectroscopy: Oh, Nh, Cn, And Ch: The State Of Current Knowledge, Svatopluk Civiš, Adam Pastorek, Martin Ferus, Sergei N. Yurchenko, Noor-Ines Boudjema

Chemistry & Biochemistry Faculty Publications

In this study, we present a current state-of-the-art review of middle-to-near IR emission spectra of four simple astrophysically relevant molecular radicals—OH, NH, CN and CH. The spectra of these radicals were measured by means of time-resolved Fourier transform infrared spectroscopy in the 700–7500 cm−1 spectral range and with 0.07–0.02 cm−1 spectral resolution. The radicals were generated in a glow discharge of gaseous mixtures in a specially designed discharge cell. The spectra of short-lived radicals published here are of great importance, especially for the detailed knowledge and study of the composition of exoplanetary atmospheres in selected new planets. Today, …


Molecular Opacities For Exoplanets, P. F. Bernath Jan 2014

Molecular Opacities For Exoplanets, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy.