Astrophysics and Astronomy Commons^™

Quantifying Dust Structure In An Elliptical Galaxy Via Optical–Near-Infrared Color Mapping: A Detailed Study Of Ngc 6251, Luke Reed

Theses and Dissertations

The giant elliptical galaxy NGC 6251 is a well-studied active radio galaxy that hosts one of the largest known relativistic jet systems, with a projected size of approximately 3 Mpc. In addition to its large-scale radio structure, the galaxy hosts a prominent circumnuclear dust feature surrounding the active nucleus, previously interpreted as a warped dust disk. This thesis focuses on the inner morphology and dust structure of NGC 6251 using archival Hubble Space Telescope observations obtained with the WFPC2 and NICMOS instruments.

The central structure of the galaxy was investigated across multiple wavelengths through image calibration, PSF modeling and subtraction, …

On The True Interstellar Anisotropy Of Tev Cosmic Rays And Its Implications For The Local Interstellar Medium, Noufel D. Maalal

Theses and Dissertations

Several ground-based cosmic ray (CR) air shower experiments have produced sky maps of intensity anisotropy in the energy range from 1 TeV to a few hundred TeVs with very high statistics and angular resolution. These measurements provide opportunities to study CR sources and propagation in the interstellar medium (ISM). Such studies present two major difficulties. Firstly, CRs are deflected by the heliospheric magnetic field on the last stretch of their journey to Earth. Secondly, measurements at different latitudes are difficult to compare, leading to uncertainties in latitudinal variations on the order of the observed anisotropy. Experiments usually assume latitudinal variations …

Manned Exploration Of Satellites Of The Outer Planets: An Analysis Of Current Technologies And A Discussion Of Advancements Required, Joshua Carson Meador

Theses and Dissertations

The Solar System’s outer planets have many satellites, some of which are known to be the most likely places to find extraterrestrial life in our celestial backyard. Multiple scientific missions have been sent to glean information from these satellites, yet the possibility of a manned expedition has long been exclusive to science fiction stories. This paper intends to collect and analyze the current state of space travel technology to explore the feasibility of such a mission with modern technology and to discuss which future advancements should be the focal point for making such missions a reality. To begin, data on …

Quantifying Noise In Monte Carlo Simulations Of Cosmic Rays In A Shock, Abhro Rahman

Theses and Dissertations

Cosmic rays are a phenomenon known to humankind from the early 1900s, and yet today the details of their physical behavior are not fully settled. While the observed spectral fluxes of cosmic rays follow a power-law trend when plotted against particle energy, the exact mechanisms under which they get to such high energies are still under study. This thesis will undertake a subsection of that task, where the Monte Carlo simulation of particle accelerations is described in Warren (2015), and we aim to identify and quantify the noise inherent in such simulations. This document takes a long path through particle …

Crimson Skies And Another Pale Blue Dot: Can Life Begin Again?, Ingrid R. Carrasco, Joseph Mocerino

Aerospace, Physics, and Space Science Student Publications

Enceladus is one of the most promising moons in our Solar System for housing an environment necessary for prebiotic synthesis or life itself. This is due to the fact that aqueous plumes ejecting form the subsurface ocean penetrate the ice shell dispersing water and subsequent organics (if present). We hypothesize that as our Sun evolves into a red giant, the increase in stellar flux will result in higher average temperatures leading to increase the potential of habitability for Enceladus.

Analyzing Hst Observations Of Ngc 6251, Ean Deuschle

Aerospace, Physics, and Space Science Student Publications

NGC 6251 is a giant elliptical radio galaxy (gEr) ~340 Mly away, hosting an AGN that produces one of the most noteworthy relativistic jets known. Using archival WFPC2 and NICMOS data, obtained from the Hubble Legacy Archive (HLA), we will present an analysis of NGC6251’s structure, dust distribution, and stellar population, to better understand the relationship between the object’s primary morphologies.

Bolide Analysis Using Ground And Jpl Cneos Data, Adrianna Patton, Cassidy Mink

Aerospace, Physics, and Space Science Student Publications

Bolides (fireballs) are meteors that explode in the atmosphere upon impact, producing an extremely bright, high-energy event, and sometimes leave recoverable fragments The project aims to develop a new analysis pipeline using JPL CNEOS government sensor data.

Exploring Possible Formation Mechanisms For Nh4sh Clouds On Jupiter, Morgan Rietmann

Aerospace, Physics, and Space Science Student Publications

Even after decades of research, much of Jupiter’s atmosphere is poorly understood. Recently, interest in a 2-3 bar cloud deck generated by a new ammonia mapping technique has exposed the very flimsy nature of the assumption that these clouds are made primarily of ammonium hydrosulfide (NH₄SH). While there is evidence to support the existence of NH₄SH at this level, its formation reaction and the interaction between this reaction and its environment has been lacking proper study. With closer inspection, the abundance of NH₃ in the atmosphere lends itself to the possible additional formation of ammonium …

Automation Of Data Analysis Of The Chandra M87 Data, Jack Becker, Kylee Fout

Aerospace, Physics, and Space Science Student Publications

Messier 87 (M87) is an elliptical galaxy known for its central black hole, and has been observed frequently over the last 20 years by the Chandra X-ray Observatory. Sourcing of the reduced observational data was done through the Chandra Data Archive, a collection of data from the Chandra Telescope. The main goal of this project was to create a data analysis pipeline that identifies spectra to search for supernovae. In addition, we would like to publish the code on GitHub, which may aid future research on transient X-ray events.

Born Dry Or Born Wet? A Palette Of Water Growth Histories In Trappist-1 Analogs And Compact Planetary Systems, Howard Chen, Matthew S. Clement, Le Chris Wang, Jesse T. Gu

Aerospace, Physics, and Space Science Faculty Publications

It is still unclear whether exoplanets in compact multiplanet systems such as TRAPPIST-1 are able to accrete large quantities of volatiles, grow to sufficient mass, and maintain robust atmospheres and hydrospheres. Previous estimates of water content in M-dwarf systems have largely relied on population synthesis or atmosphere–interior evolution models, often treating impacts and atmospheric loss in isolation. In this work, we combined impact delivery, impact erosion, and mantle-atmosphere exchange within a unified framework that tracks volatile evolution through stochastic collision histories. By explicitly including both planetesimal accretion and the prolonged luminous pre-main-sequence phase of M dwarfs, we find systematically lower …

Investigating Global Lightning Observed From Ground And Space, And Its Relationship To Solar Activity, Megan Diane Mark

Theses and Dissertations

The extremes of lightning, specifically lightning with long-lasting continuing currents and lightning with extremely high peak currents, are investigated from both ground- and space-based observations. Additionally, the potential solar influence on lightning is investigated on large spatial scales.

Continuing currents may occur following the impulsive flow of current during a cloud-to-ground (CG) return stroke and are usually low amplitude (from a few amperes to a few kiloamperes) and long duration (several to hundreds of milliseconds). Remotely estimating their duration from the electromagnetic fields measured by existing ground-based lightning locating systems (LLSs) is not possible, but some space-based lightning detection systems …

On The Nature Of Low-Frequency Power Spectra In Solar Wind Turbulence, Mason Alden Dorseth

Theses and Dissertations

An important challenge in the accurate estimation of power spectra of plasma fluctuations in the solar wind at very low frequencies is that it requires extremely long signals, which will necessarily contain a mixture of qualitatively different solar wind streams. This unavoidably affects the structure of the power spectra by conflating all these different properties into a single power spectrum. This work develops a conditional statistical analysis to accurately estimate the power spectrum at arbitrarily low frequencies for ``pure'' slow solar wind stream, based on estimated autocorrelation functions of signals excluding portions that do not satisfy the required conditions. The …

Unraveling The Physics Of Quasar Jets Using Hst Polarimetry, Devon Clautice

Theses and Dissertations

We present a multiwavelength study of three high-power FR II (quasar) jets -- 3C 273, PKS 0637-752, and 1150+497 -- with an emphasis on new high-quality Hubble Space Telescope (HST) optical polarimetry and Chandra X-ray Observatory imaging. Relativistic jets from active galactic nuclei transport energy and mass from the supermassive black hole’s accretion region out to Megaparsec-scale lobes, with effects that feedback into galaxy formation and cluster energetics. We build on recent work which has called into question our fundamental understanding of FR II jet physics, and suggest that highly-efficient particle acceleration must be taking place in situ …

Modeling An Extra Planet's Effects On Earth, Emily Simpson

Aerospace, Physics, and Space Science Student Publications

Orbital dynamics play a crucial role in determining the habitability of exoplanets, and many models have been developed to study the dynamical evolution of broader planetary system structure. To further investigate the implications this has regarding planetary habitability, this project simulated the evolution of the Solar System with an additional planet orbiting in place of the Asteroid Belt using the Gravitational Rigid-body InTegrator (GRIT) package. 21 total simulations were run for 100,000 years with varying values for the extra planet’s mass (from 0.01 to 10 Earth masses) and orbital parameters (based on the 4 most massive asteroids in the Asteroid …

Deuterium Escape On Photoevaporating Sub-Neptunes, Pin-Gao Gu, Howard Chen

Aerospace, Physics, and Space Science Faculty Publications

We investigate the evolution of the deuterium-to-hydrogen (D/H) mass ratio driven by EUV photoevaporation of hydrogen-rich atmospheres of close-in sub-Neptunes around solar-type stars. For the first time, the diffusion-limited approach in conjunction with energy-limited photoevaporation is considered in evaluating deuterium escape from evolving exoplanet H/He envelopes. We find that the planets with smaller initial gas envelopes and thus smaller sizes can lead to weaker atmospheric escape, which facilitates hydrogen–deuterium fractionation. Specifically, in our grid of simulations with a low envelope mass fraction of less than 0.005, a low-mass sub-Neptune (4–5 M⊕) at about 0.25–0.4 au or a high-mass sub-Neptune …

A Comparison Of Automated Bolide Detection Methods, Maxine Thembi Khumalo

Theses and Dissertations

Bolide recording and analysis are crucial so meteoroid fragments can be found, a lightcurve analyzed, and its trajectory calculated. The Spalding Allsky Camera Network (SACN) generates videos and composite images of the night sky that are potential meteors based on changes in brightness. The best way to ensure quick identification is to automate the detection of bolides (and all meteors) using computational techniques. This project tested three algorithms to sort events between those with and without meteors - a Traditional Hough Detection Method, Convolutional Neural Network (CNN), and YOLOv5 against the previous technique from 2018 by Elena Botella. All the …

Sporadic Spin-Orbit Variations In Compact Multiplanet Systems And Their Influence On Exoplanet Climate, Howard Chen, Gongjie Li, Adiv Paradise, Ravi K. Kopparapu

Aerospace, Physics, and Space Science Faculty Publications

Climate modeling has shown that tidally influenced terrestrial exoplanets, particularly those orbiting M-dwarfs, have unique atmospheric dynamics and surface conditions that may enhance their likelihood to host viable habitats. However, sporadic libration and rotation induced by planetary interactions, such as those due to mean motion resonances (MMR) in compact planetary systems, may destabilize attendant exoplanets away from synchronized states (1:1 spin-orbit ratios). Here, we use a three-dimensional N-rigid-body integrator and an intermediately complex general circulation model to simulate the evolving climates of TRAPPIST-1 e and f with different orbitaland spin-evolution pathways. Planet f scenarios perturbed by MMR effects with chaotic …

Investigating The O’Connell Effect In Kepler Eclipsing Binaries, Matthew Frederick Knote

Theses and Dissertations

The O’Connell effect – the presence of unequal maxima in eclipsing binaries – remains an unsolved riddle in the study of close binary systems. The Kepler space telescope produced high precision photometry of nearly 3,000 eclipsing binary systems, providing a unique opportunity to study the O’Connell effect in a large sample and in greater detail than in previous studies. I have characterized the observational properties – including temperature, luminosity, and eclipse depth – of a set of 212 systems (7.3% of Kepler eclipsing binaries) that display a maxima flux difference of at least 1%, representing the largest sample of O’Connell …

Infrared Search For N-Butane And Trans-2-Butene In Titan’S Atmosphere, Brendan Steffens

Theses and Dissertations

This dissertation constitutes a study of the possible presence of trace hydrocarbons, namely n-butane (n-C4H10) and trans-2-butene (trans-2-C4H8) in Titan’s atmosphere. These molecules, both of which bear specific connections of interest to Titan’s astrobiological potential, are predicted by photochemical models to occur at detectable abundances within Titan’s atmosphere. In spite of this, neither has been detected to date, by any means. For this work, both of these molecules were characterized in the laboratory by obtaining a comprehensive set of highresolution, infrared cross section measurements at cold temperatures appropriate for Titan. In the case of n-butane, a pseudoline list (i.e. an …

The Development Of A New All-In-One Allsky Camera And Radiometer System, Ashley Suzanne Hughes

Theses and Dissertations

We developed a new all-in-one camera and radiometer system for meteor surveillance. It proved successful during its first bolide event on 13 April 2021, as reported in the journal Meteoritics and Planetary Science, volume 57, number 3, pages 575-587. The event capture produced both video and radiometric data, and with the video data we were able to calculate a trajectory and orbit, and determine the fragmentation characteristics of the meteor as it traveled through the atmosphere.

Extreme-Contrast Ratio Imaging Of Bright Star Fields Using Charge-Injection Devices, Sailee Mangesh Sawant

Theses and Dissertations

The intrinsic nature of many astronomical sources, such as exoplanets, binary and multiple star systems, circumstellar disks, and active galactic nuclei and their host galaxies, introduces challenging requirements for observational instrumentation and techniques. In each case, we encounter situations where the light from bright sources hampers our abilities to detect surrounding fainter targets. To explore and study all features of such extreme-contrast ratio (ECR) scenes, we must perform observations at the maximum possible contrast ratios. However, direct imaging of fainter objects in the vicinity of bright sources imposes limitations on the type of contrast ratios achievable using ground- and spacebased …

Arion 33: A Prospective Mission To Near-Earth Asteroids, Alita Regi

Theses and Dissertations

Near-Earth asteroids will become primary targets for space industrialization in the future as humanity becomes a multi-planetary species. But before such missions, it is necessary to survey these asteroids for their intrinsic scientific value. Exploring asteroids via orbiter missions can help us understand the asteroid's surface composition while providing us a cost and power model required for future missions. Therefore, it is beneficial to study asteroids to pave the way for future mining operations or more comprehensive scientific explorations. Hence, in this thesis, the target asteroids 2011 UW158 and 65803 Didymos are selected as case studies for the hypothetical mission …

Intermittency Scaling Laws In Magnetohydrodynamic Turbulence: Theory, Simulations And Observations, Juan Carlos Palacios Caicedo

Theses and Dissertations

The main objective of this dissertation is to investigate intermittency of Magnetohydrodynamic (MHD) plasmas by means of high-resolution numerical simulations and large sets of solar wind data. Understanding intermittency scaling laws is a significant step forward towards understanding the fundamental properties of plasma turbulence and how spatial structures influence dissipation, heating, transport and acceleration of charged particles, which is important in a wide range of laboratory, space and astrophysical plasmas. The current stateof- the art in the theoretical understanding of intermittency in MHD turbulence is based on phenomenological (non-exact) models, numerical simulations and solar wind observations of structure functions of …

A Numerical Study Of Jovian Moist Convection With A New Convective Adjustment Scheme, And Implications For Jupiter’S Water Abundance, Ramanakumar Sankar

Theses and Dissertations

Jupiter’s atmosphere features a variety of clouds that are formed from the interplay of chemistry and atmospheric dynamics, from the deep red of the Great Red Spot to the high altitude white ammonia clouds present in the zones. Beneath these upper level clouds, water condensation occurs, and sporadically leads to the formation of towering convective storms, driven by the release of large amounts of latent heat. These storms result in a widespread disruption of the cloud and dynamical structure of the atmosphere at the latitude where they form, making the study of these events paramount in understanding the dynamics at …

Timing Properties Of Active Galactic Nuclei, Evan Arnold Smith

Theses and Dissertations

Timing properties of Active Galactic Nuclei (AGN) are investigated primarily using archival data from the Rossi X-ray Timing Explorer (RXTE) satellite collected between 1996 and 2011. The main emphasis is to search for quasi-periodic oscillations (QPOs). This search was motivated by the uniqueness of the RXTE AGN database, which contains a gold-mine of information on the long-term light curves of AGN, as well as the fact that QPOs are a common feature in the light curves of stellar mass black hole (BH) and neutron star (NS) X-ray Binaries (XRBs).In stellar mass systems, QPOs have been used as strong diagnostics about …

The Solar Energetic Particle Event Of 2010 August 14: Connectivity With The Solar Source Inferred From Multiple Spacecraft Observations And Modeling, D. Lario, R.-Y. Kwon, I. G. Richardson, N. E. Raouafi, B. J. Thompson, T. T. Von Rosenvinge, M. L. Mays, P. A. Makela, H. Xie, H. M. Bain, M. Zhang, L. Zhao, H. V. Cane, A. Papaioannou, N. Thakur, P. Riley

Aerospace, Physics, and Space Science Faculty Publications

We analyze one of the first solar energetic particle (SEP) events of solar cycle 24 observed at widely separated spacecraft in order to assess the reliability of models currently used to determine the connectivity between the sources of SEPs at the Sun and spacecraft in the inner heliosphere. This SEP event was observed on 2010 August 14 by near-Earth spacecraft, STEREO-A (∼80° west of Earth) and STEREO-B (∼72° east of Earth). In contrast to near-Earth spacecraft, the footpoints of the nominal magnetic field lines connecting STEREO-A and STEREO-B with the Sun were separated from the region where the parent fast …

A Compositional Analysis Of Artificial And Terrestrial Analog Martian Regolith Simulants, Beverly Watson Kemmerer

Theses and Dissertations

Over the past 50 years, significant advances in the knowledge of the topography, climate, and geology of Mars have taken place. The global Martian regolith composition is highly basaltic, primarily composed of pyroxene, plagioclase, and olivine, a mixture of Fe oxides and Fe-Ti oxides, and some alteration minerals, i.e. sulfates, carbonates, and clays. The particle size distribution of Martian regolith ranges from 1 µm to 1000 µm, with average Martian soil grain sizes being 250 µm to 300 µm. These regolith properties, as well as geotechnical properties, all play a part in the outcome of certain in situ resource utilization …

Deep Space Radiation Shelter Through Magnetic Shielding, Lauren Elizabeth Eastberg Persons

Theses and Dissertations

As human space exploration begins to reach beyond Earth for the first time in 50 years, we must prepare for the eventuality of long-duration missions outside the protection of Earth's magnetic field. In interplanetary space astronauts are exposed to highly energetic galactic cosmic radiation, most commonly in the range of 1-GeV protons. Present day shielding technologies are not sufficient to protect astronauts against such particles; as such, the following paper proposes an alternate method of creating deep space radiation shelters through the use of magnetic shielding. Using a series of circular superconducting loops arranged in the shape of a shell, …

Advanced Astroinformatics For Variable Star Classification, Kyle Burton Johnston

Theses and Dissertations

This project outlines the complete development of a variable star classification algorithm methodology. With the advent of Big-Data in astronomy, professional astronomers are left with the problem of how to manage large amounts of data, and how this deluge of information can be studied in order to improve our understanding of the universe. While our focus will be on the development of machine learning methodologies for the identification of variable star type based on light curve data and associated information, one of the goals of this work is the acknowledgment that the development of a true machine learning methodology must …

Biosignature Anisotropy Modeled On Temperate Tidally Locked M-Dwarf Planets, Howard Chen, Eric T. Wolf, Ravi Kopparapu, Shawn Domagal-Goldman, Daniel E. Horton

Aerospace, Physics, and Space Science Faculty Publications

A planet’s atmospheric constituents (e.g., O2, O3, H2Ov, CO2, CH4, and N2O) can provide clues to its surface habitability, and may offer biosignature targets for remote life detection efforts. The plethora of rocky exoplanets found by recent transit surveys (e.g., the Kepler mission) indicates that potentially habitable systems orbiting K- and M-dwarf stars may have very different orbital and atmospheric characteristics than Earth. To assess the physical distribution and observational prospects of various biosignatures and habitability indicators, it is important to understand how they may change under different astrophysical and geophysical configurations, and to simulate these changes with …