The Role Of Volatile Enrichment In The Radiogenic Heating And Thermal Evolution Of Rocky Exoplanets, 2023 Western Washington University
The Role Of Volatile Enrichment In The Radiogenic Heating And Thermal Evolution Of Rocky Exoplanets, Ula Jones, Asmaa Boujibar
WWU Honors College Senior Projects
Internal heating in terrestrial planets is a fundamental physical process controlling the internal structure of a planet, mantle convection, volcanic activity, and the generation of magnetic fields. Internal heating results from various processes including radioactive decay and accretional energy, as well as additional irradiation and tidal heating in planets with short orbital periods. The largest long-term heat source for terrestrial planets is radioactive heating, especially from the decay of uranium (U), thorium (Th), and potassium (K) isotopes. K is a moderately volatile element, while U and Th are refractory elements; during planetary accretion volatiles are depleted relative to refractory elements, …
Stellar Atmosphere Models For Select Veritas Stellar Intensity Interferometry Targets, 2023 Embry-Riddle Aeronautical University
Stellar Atmosphere Models For Select Veritas Stellar Intensity Interferometry Targets, Jackson Ladd Sackrider, Jason P. Aufdenberg, Katelyn Sonnen
Beyond: Undergraduate Research Journal
Since 2020 the Very Energetic Radiation Imaging Telescope Array System (VERITAS) has observed 48 stellar targets using the technique of Stellar Intensity Interferometry (SII). Angular diameter measurements by VERITAS SII (VSII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars …
Looking For Life, 2023 Gettysburg College
Looking For Life, Conor C. Grubb
CAFE Symposium 2023
The topic of aliens is not just about conspiracy theories and tinfoil hats, through the years numerous respected scientists have weighed in and put thought into the topic. The Search for Extraterrestrial Intelligence (SETI) is closely tied to the Fermi Paradox and the Drake Equation. The Fermi Paradox considers why humans haven't already interacted with aliens if they exist, and the Drake Equation outlines potential variables that would influence the chances of humanity receiving radio contact from an alien civilization.
Measurement Of Near-Threshold Proton Branching Ratios In 31s Important For Novae, 2023 Louisiana State University and Agricultural and Mechanical College
Measurement Of Near-Threshold Proton Branching Ratios In 31s Important For Novae, Sudarsan Balakrishnan
LSU Doctoral Dissertations
Classical novae are stellar explosions that contribute to the nucleosynthesis of isotopes on the proton-rich side of the valley of stability up to 40Ca. In ONe novae, the incompletely understood reaction rate of 30P(p,γ)31S is known to strongly influence the production rate of several stable isotopes such as 30Si, 31P, and 32,33,34S. A precise measurement of this reaction rate has several potential implications towards matching astrophysical observables to the physical composition of the nova site -- the observed elemental abundance ratios of O/S and S/Al have been suggested as useful `thermometers' to gauge …
Astr 1: General Astronomy, 2023 CUNY Queens College
Astr 1: General Astronomy, David Goldberg
Open Educational Resources
No abstract provided.
Tracing The Most Powerful Galactic Cosmic-Ray Accelerators With The Hawc Observatory, 2023 Michigan Technological University
Tracing The Most Powerful Galactic Cosmic-Ray Accelerators With The Hawc Observatory, Dezhi Huang
Dissertations, Master's Theses and Master's Reports
Since Victor Hess's groundbreaking detection of cosmic rays in the Earth's atmosphere in 1912, the origins of these charged particles have remained an enduring mystery. Recent studies suggest that these cosmic rays are accelerated beyond Peta electronvolts by powerful astrophysical sources within our own galaxy. While the cosmic rays themselves are being deflected in all directions by magnetic fields, the gamma rays produced by them, being electrically neutral, travel to the observer in a straight line. They carry crucial information, allowing us to trace cosmic-ray accelerators within our galaxy. The High Altitude Water Chrenkov (HAWC) Observatory, located on the slopes …
A Search For Compact Object Dark Matter In The Universe Utilizing Gravitational Millilensing Of Gamma-Ray Bursts, 2023 Michigan Technological University
A Search For Compact Object Dark Matter In The Universe Utilizing Gravitational Millilensing Of Gamma-Ray Bursts, Oindabi Mukherjee
Dissertations, Master's Theses and Master's Reports
In this dissertation, I explore the existence of Compact Object (CO) Dark Matter (DM), examining its predicted millilensing impact on the light curves of Gamma-Ray Bursts (GRBs). The hypothesis under investigation is that if CO DM exists, it will act as a gravitational lens, influencing light emanating from GRBs and creating a measurable gravitational echo. The detection of this echo is conditional on several factors, including the spatial alignment of the observer, lens, and source and the mass of the CO DM.
Recent studies have reported the potential detection of millilensing in several GRBs, including GRB 950830, GRB 081122A, GRB …
Applications Of Digital Filters In Radio Astronomy, 2023 West Virginia University
Applications Of Digital Filters In Radio Astronomy, Joseph William Kania
Graduate Theses, Dissertations, and Problem Reports
The radio sky spans tens of orders of magnitude in length, density, and time.
In this thesis, using novel filtering techniques and two different telescopes,
we investigate two tracers of cosmic structure: Baryon Acoustic Oscillations
(BAOs) and Fast Radio Bursts (FRBs). BAOs formed as the universe cooled
after the Big Bang. BAOs provide a fiducial length scale of the universe
throughout cosmic time and thus can be used to understand how the universe
is evolving. FRBs are very bright, short timescale, bursts of as-yet unknown
origin which occur uniformly on the sky at a rate of a few thousand per …
A Numerical Approach To Solve The Initial-Value Problem Of Two-Body With Universal Variable, 2023 Space Science Dep., Fac., of navigation Science and Space Technology (NSST), Beni-Suef Uni., Egypt
A Numerical Approach To Solve The Initial-Value Problem Of Two-Body With Universal Variable, Ahmed B. Yassen, Waleed N. Ahmed, Ahmed H. Ibrahim, Abdelaziz A. Bakry, Hany R. Dwidar
Al-Azhar Bulletin of Science
The solution of the initial-value problem of two-body gives inaccurate final state predictions for the orbital motions of artificial satellites. This is due to the presence of singularities and the poor selection of variables. In the current study, we numerically investigated the initial-value problem using the universal anomaly approach. To clarify the problem under concern, we carried out several numerical examples using a homemade software package. We considered five space missions, around the two planets Earth and Venus, which represent circular, near circular and ellipse orbits. We showed that the universal anomaly approach facilitates the numerical and analytical treatments of …
Black Holes, Disk Structures, And Cosmological Implications In E-Dimensional Space, 2022 Chapman University
Black Holes, Disk Structures, And Cosmological Implications In E-Dimensional Space, Subhash Kak, Menas C. Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We examine a modern view of the universe that builds on achieved successes of quantum mechanics, general relativity, and information theory, bringing them together in integrated approach that is founded on the realization that space itself is e-dimensional. The global and local implications of noninteger dimensionality are examined, and how it may have increased from the value of zero to its current value is investigated. We find surprising aspects that tie to structures in the universe, black holes, and the role of observations.
Multifrequency Scintillation In The Polar Caps, 2022 Embry-Riddle Aeronautical University
Multifrequency Scintillation In The Polar Caps, Tate Colby
Doctoral Dissertations and Master's Theses
In the ionosphere, plasma density structures with scales sizes ranging from a few centimeters to hundreds of kilometers are capable of modifying the phase and amplitude of a radio signal in a rapid random manner in a process called scintillation. The Coherent Electromagnetic Radio Tomography (CERTO) and the Canadian High Arctic Ionospheric Network (CHAIN) are two different networks of scintillation receivers, each with a station in Resolute Bay, Canada. CERTO measures amplitude and phase signals in VHF and UHF while CHAIN measures amplitude and phase signals in the L-band. Through these measurements we can calculate the scintillation indexes, S_4 and …
Core-Collapse Supernova Simulations With Spectral Two-Moment Neutrino Transport, 2022 University of Tennessee, Knoxville
Core-Collapse Supernova Simulations With Spectral Two-Moment Neutrino Transport, Ran Chu
Doctoral Dissertations
The primary focus of this dissertation is to develop a next-generation, state-of-the-art neutrino kinetics capability that will be used in the context of the next-generation, state-of-the-art core-collapse supernova (CCSN) simulation frameworks \thornado\ and \FLASH.\index{CCSN} \thornado\ is a \textbf{t}oolkit for \textbf{h}igh-\textbf{or}der \textbf{n}eutrino-r\textbf{ad}iation hydr\textbf{o}dynamics, which is a collection of modules that can be incorporated into a simulation code/framework, such as \FLASH, together with a nuclear equation of state (EOS)\index{EOS} library, such as the \WeakLib\ EOS tables. The first part of this work extends the \WeakLib\ code to compute neutrino interaction rates from~\cite{Bruenn_1985} and produce corresponding opacity tables.\index{Bruenn 1985} The processes of emission, …
Dirac Dark Matter, Neutrino Masses, And Dark Baryogenesis, 2022 (Instituto de Física, Universidad de Antioquia, Medellín, Colombia; Instituto de Física Gleb Wataghin, UNICAMP, Campinas, Brazil
Dirac Dark Matter, Neutrino Masses, And Dark Baryogenesis, Diego Restrepo, Andrès Rivera, Walter Tangarife
Physics: Faculty Publications and Other Works
We present a gauged baryon number model as an example of models where all new fermions required to cancel out the anomalies help to solve phenomenological problems of the standard model (SM). Dark fermion doublets, along with the isosinglet charged fermions, in conjunction with a set of SM-singlet fermions, participate in the generation of small neutrino masses through the Dirac-dark Zee mechanism. The other SM-singlets explain the dark matter in the Universe, while their coupling to an inert singlet scalar is the source of the CP violation. In the presence of a strong first-order electroweak phase transition, this “dark” CP …
Using Neural Network To Search For Isolated Hα Clouds In The Virgo Cluster, 2022 University of Alabama in Huntsville
Using Neural Network To Search For Isolated Hα Clouds In The Virgo Cluster, Audra Carver
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Mining The Data Cubes In Sub-Mm And Optical Astronomy, 2022 University of Alabama in Huntsville
Mining The Data Cubes In Sub-Mm And Optical Astronomy, Nathanael Pichette
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Stacking The Gamma-Ray Sky To Search For Faint Astrophysical Populations, 2022 The Graduate Center, City University of New York
Stacking The Gamma-Ray Sky To Search For Faint Astrophysical Populations, Yuzhe Song
Dissertations, Theses, and Capstone Projects
Gamma-ray emission can be generated from a wide variety of high-energy astrophysical phenomena, from stellar flares to pulsating neutron stars, and from interstellar clouds to the center of the Milky Way Galaxy. Entering the 13th year of its orbit around Earth, the Fermi Space Gamma-ray Telescope has been continually surveying the γ-ray sky with its Large Area Telescope (LAT) on board. The latest Fermi source catalog contains over 6000 sources. Yet, a lot of sources that are expected to emit γ-rays are not detected, and only small percentages of some populations are detected. For example, solar flares are detected in …
Astrophysics, Cosmology And Particle Phenomenology At The Energy Frontier, 2022 The Graduate Center, City University of New York
Astrophysics, Cosmology And Particle Phenomenology At The Energy Frontier, Jorge Fernandez Soriano
Dissertations, Theses, and Capstone Projects
This dissertation consists of two parts, treating significantly separated fields. Each part consists on several chapters, each treating a somewhat isolated topic from the rest. In each chapter, I present some of the work developed during my passage through the graduate program, which has mostly been published elsewhere.
Part I – Cosmic Rays and Particle Physics
- Chapter 1: In this chapter we present an introduction to the topic of cosmic ray physics, with an special focus on the so-called ultra high energy cosmic rays: their potential origins, effects during their propagation between their sources and Earth, the different techniques used …
Development Of High-Resolution Meteor Spectra Analysis, 2022 Western University
Development Of High-Resolution Meteor Spectra Analysis, Zhangqing Yang
Undergraduate Student Research Internships Conference
Meteoroids are often billions of years old and as they ablate and ionize in the atmosphere, they give off light leaving us clues to the history of our solar system. In addition, their presence imposes serious risks to our equipment and astronauts in space. My research deals with analyzing High-Resolution Meteor Spectra, which are obtained by separating the light Meteors give off through a Diffraction Grating. Firstly, as the Meteor’s speed during ablation affects its spectrum, the position, speed, and trajectory of 40 well-tracked Meteors (picked from over 500) were determined using the programs Metal and Mirfit. Then, the spectra …
The Pursuit For Gamma-Ray Emitting Pulsar Wind Nebulae With The Fermi-Large Area Telescope, 2022 Clemson University
The Pursuit For Gamma-Ray Emitting Pulsar Wind Nebulae With The Fermi-Large Area Telescope, Jordan Eagle
All Dissertations
Pulsar wind nebulae are highly magnetized particle winds, descending from core collapse supernovae (CC SNe), and each powered by an energetic, rapidly rotating neutron star. There are at least 125 Galactic pulsar wind nebulae (PWNe) that have been discovered from radio wavelengths to TeV gamma-rays, the majority of which were first identified in radio or X-ray surveys. An increasing number of PWNe are being identified in the TeV band by ground-based air Cherenkov Telescopes such as HESS, MAGIC, and VERITAS such that they constitute the dominant source class of Galactic TeV emitters. High-energy sources like PWNe may be responsible for …
Co Molecular Spectroscopy And Spectro-Astrometry Of Protoplanetary Disks, 2022 Clemson University
Co Molecular Spectroscopy And Spectro-Astrometry Of Protoplanetary Disks, Stanley Jensen
All Dissertations
Until relatively recently, the only known planets were those in our own solar system (Mayor & Queloz, 1995). However modern instruments and techniques have revealed that planets are ubiquitous around main sequence stars over the last three decades. From this we have obtained a multitude of insights into planetary populations. For instance, while the terrestrial and gas giant planet types are both well accounted for in extra-solar systems, the arrangement of our own system with inner terrestrial planets and outer gas giants is not clearly the typical organization (van der Marel & Mulders, 2021). In fact we see that in …