Stars, Interstellar Medium and the Galaxy Commons^™

Density And Magnetic Field Asymmetric Kelvin‐Helmholtz Instability, Xuanye Ma, Peter Delamere, Katariina Nykyri, Antonius Otto, Stefan Eriksson, Lihui Chai, Brandon Burkholder, Andrew Dimmock, Yu-Lun Liou, Shiva Kavosi

Publications

The Kelvin‐Helmholtz (KH) instability can transport mass, momentum, magnetic flux, and energy between the magnetosheath and magnetosphere, which plays an important role in the solar‐wind‐ magnetosphere coupling process for different planets. Meanwhile, strong density and magnetic field asymmetry are often present between the magnetosheath (MSH) and magnetosphere (MSP), which could affect the transport processes driven by the KH instability. Our magnetohydrodynamics simulation shows that the KH growth rate is insensitive to the density ratio between the MSP and the MSH in the compressible regime, which is different than the prediction from linear incompressible theory. When the interplanetary magnetic field (IMF) …

Observed Epochal Variations In X-Ray Lines From The O Supergiant Ζ Puppis Do Not Require Substantial Changes In The Wind Mass Flux, Sean J. Gunderson, Kenneth G. Gayley, David P. Huenemoerder, Pragati Pradhan, Nathan A. Miller

Publications

We fit the high-resolution Chandra X-ray spectra of the O supergiant ζ Puppis using the variable boundary condition (VBC) line model to test the stability of its mass-loss rate between two epochs of observation: 2000 March and 2018 July – 2019 August. At issue is whether the observed variations are induced by global changes in the cool (unshocked) wind itself or are isolated to the local pockets of hot gas (i.e. changes in the frequency and location of the shocks). Evidence in the literature favoured the possibility of a 40 per cent increase in the mass flux of the entire …

Life Beyond The Horizon: The Universe Was Born In A Black Hole, Zahria Patrick

Undergraduate Research Symposium

It is a widely accepted fact that obtaining information about a black hole is a near-impossible task without being stretched like a spaghetti noodle and trapped in one due to its strong gravitational pull. If the universe exists in a black hole, however, it will mean that it could be possible to survive after crossing its inescapable borders. As surprising as all of this may seem, this theory has existed for quite a while amongst a few different physicists. One person that has shed light on and expanded people’s knowledge of this frightening theory is theoretical physicist, Nikodem Poplawski. The …

Analysis Of Neutron Star Structure And Equation Of State Using Computational Simulations, Sohila Sameh

2024 REYES Proceedings

Understanding neutron star structures is crucial for advancing astrophysical research. This study explores the structure of neutron stars using advanced equations, including the Tolman-Oppenheimer-Volkoff (TOV) equations, and various equations of state (EoS). We investigate the mass-radius relationship, stability criteria, and cooling mechanisms. Key findings highlight the impact of relativistic corrections and rotational effects on neutron star properties. The results demonstrate how integrating these advanced equations enhances the understanding of neutron star behavior and stability. This research provides a comprehensive framework for analyzing neutron star structures, with implications for future astrophysical studies.

Nuclear Physics And Neutron Stars: Structure Of Compact Stellar Objects, Michel Geralddi Coria Magaña

2024 REYES Proceedings

The Tolman-Oppenheimer-Volkoff (TOV) equations provide a theoretical framework for modeling the structure of neutron stars and white dwarfs in hydrostatic equilibrium. Using Python and MATLAB, we simulate the mass-radius relationship, pressure, and density profiles of these compact stars, focusing on how ionized plasma dynamics contribute to their stability. By incorporating particle simulations into the visualization process, we model the internal forces of neutron stars and white dwarfs, demonstrating how computational tools offer unique insights into these celestial objects. The results align well with theoretical predictions and provide a solid foundation for future studies incorporating additional physical effects such as magnetic …

A Computational Study On The Structural Limits Of Neutron Stars Under Relativistic Conditions And Nuclear Phenomena, Marcelo Siles

2024 REYES Proceedings

This project investigates the modeling of neutron stars and white dwarfs using polytropic equations of state and relativistic corrections. By integrating relativistic effects into the Tolman-Oppenheimer-Volkoff (TOV) equations, we obtain more accurate predictions of neutron star properties, including mass-radius relationships and neutron degeneracy pressure. Non-relativistic models are inadequate under high pressures. Considering nucleon-nucleon interactions suggests that neutron stars can surpass the Tolman-Oppenheimer-Volkoff limit, theoretically reaching masses up to 2.3 𝑀_⊙. However, empirical data supports a more realistic mass range of 1.5 to 2.3 𝑀_⊙. The inclusion of neutron star crust modeling refines these predictions, indicating possible …

The A²Π-X²Σ⁺ Band System Of Sco For M-Type Star Spectral Analysis, Léo Lavy, Adam Pastorek, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

M-type stars are the most abundant stars in our Galaxy. Their visible spectra are characterized by strong TiO and VO absorption bands with occasional ScO bands near 6000–6100 Å. This region corresponds to the A²Π–X²Σ⁺ band system and can be used to measure the abundance of ScO. In this work, a new Doppler-limited resolution spectrum of ScO obtained in a hollow-cathode experiment is presented. The A²Π–X²Σ⁺ electronic transition is analyzed with special care dedicated to fitting the A′²Δ(v+2) ∼ A²Π(v) perturbation. Spectroscopic constants of the A²Π(v) states are reported for v ≤ 9, and a partial fit of …

The Computational Search For Unidentified Central Configurations Of The Newtonian N-Body Problem, Hannah G. Havel

CURE Proceedings

The N-body problem is a field of study in mathematics and physics that involves predicting the motion of particles moving under their mutual gravitational attraction. It is vital in celestial mechanics, such as planning collision-free satellite orbit trajectories. When beginning to understand the N-body problem, we can start by looking at equal masses of these particles or celestial bodies. As particles move, their position and velocity change, both energy and angular momentum are conserved. Sets of constant energy and angular momentum, known as integral manifolds, are higher-dimensional figures that represent constraints of movement to a system. Integral manifolds are described …

Analysis Of Pulsar Discoveries And Pulse Profile Variability: From Pulsar Candidates To Gravitational Wave Detector, William Carl Fiore

Graduate Theses, Dissertations, and Problem Reports (ETD)

Last year, pulsar timing arrays (PTAs) reported evidence of a gravitational-wave (GW) background at nanohertz frequencies, opening a new window into the Universe. PTAs measure GW-induced variations in the timing of radio pulses from millisecond pulsars (MSPs) in our Galaxy. In order for PTA experiments to confidently detect and characterize the GW background, they must continue to regularly observe many MSPs and measure their pulse times of arrival as precisely as possible. This motivates efforts to find new MSPs with pulsar surveys, and to study pulsars whose unusual behavior may give rise to excess noise in PTA data sets, potentially …

Possible Evidences For Existence Of An Aether Medium (Or Virtual Inertia/Spin Superfluid Medium), Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

The presentation explores the possibility of an aether medium, also referred to as a virtual inertia/spin superfluid medium, existing to explain certain physical phenomena. While the concept of an aether has been historically rejected by mainstream physics, recent findings and interpretations offer potential justifications for its reconsideration. After discussions with several physicists, notably Robert N. Boyd, PhD and others, we are convinced that aether medium does exist, or may be called virtual inertia/spin superfluid medium.

Constructing The 4th Hawc Catalog Of Very-High-Energy Sources Using An Automated Likelihood Pipeline Search, Samuel J. Groetsch

Dissertations, Master's Theses and Master's Reports

In this thesis, I present an analysis pipeline that allows one to search for and identify sources of very-high-energy (VHE) γ-ray emission in sky maps created from data collected with the High Altitude Water-Cherenkov (HAWC) Observatory. The HAWC Observatory is located at about 4100 m elevation just below Pico de Orizaba, the highest mountain in Mexico also known as Citlaltepetl (from the Nahuatl words citlal(in) = star, and tepetl = mountain). The observatory is an array of several hundred detector stations that measure signals from particle showers, so-called extensive air showers (EAS), that are initiated in interactions of primary cosmic …

The A²Π–X²Σ⁺ Band System Of Yo, Peter F. Bernath, Manish Bhusal, Adam Pastorek

Chemistry & Biochemistry Faculty Publications

YO bands are conspicuous in the spectra of S stars. The laboratory spectrum of the A²Π–X²Σ⁺ electronic transition has been recorded with a Fourier transform spectrometer using a composite-wall hollow cathode lamp source. The A²Π–X²Σ⁺ transition with v ' ≤ 4 and v'' ≤ 4 has been rotationally analyzed using the modern spectral fitting program PGOPHER. Vibronic band strengths were calculated using an ab initio transition dipole moment function. A line list for the A²Π–X²Σ⁺ transition is provided and can be utilized in the modeling …

Opacities Of S-Type Stars: The Singlet B¹⊓−X¹Σ⁺, B¹⊓−A¹Δ, And C¹Σ⁺−X¹Σ⁺ Band Systems Of Zro, Peter F. Bernath, Manish Bhusal, Jacques Liévin

Chemistry & Biochemistry Faculty Publications

The ZrO B¹Π–X¹Σ⁺, B¹Π–A¹Δ, and C¹Σ+–X¹Σ⁺ band systems are important opacity sources in the near-infrared and optical spectra of S-type stars. A total of 21 rovibronic bands with v'' ≤ 7 and v' ⩽ 5 were observed and fit for the B¹Π–X¹Σ⁺ transition, five bands for the ⁹⁰ZrO B¹Π–A¹Δ transition and one band for the ⁹⁰ZrO C¹Σ⁺–X¹Σ⁺ transition. All band …

A Multi-Wavelength Determination Of The Total Luminosity And Star Formation Rate Of The Milky Way, Joshua L. Mascoop

Graduate Theses, Dissertations, and Problem Reports (ETD)

The star formation rate (SFR) of the Milky Way is poorly understood in comparison to the SFR of other galaxies. In order to better find the Galaxy's place in the universe, it is imperative to understand the star formation activity occurring within it. We characterize the Galactic \hii\ region luminosity function (LF) at multiple infrared and radio wavelengths using a sample of 797 first Galactic quadrant \hii regions compiled from the WISE Catalog of Galactic \hii Regions. This sample is statistically complete for all regions powered by single stars of type O9.5V and earlier.

We find that neither a single …

Spinning Spheroidal Components Of Disk Galaxies: Resonant Interactions With Stellar Bars, Xingchen Li

Theses and Dissertations--Physics and Astronomy

The majority of disk galaxies possess stellar bars, which are the main driver in the internal evolution of barred galaxies. Bars represent non-axisymmetric perturbations in the galactic disks, producing strong gravitational torques that facilitate angular momentum transfer from the disk to the spheroidal components, such as central stellar bulges and host dark matter (DM) halos. The redistribution of angular momentum in barred galaxies proceeds mainly via resonant interactions between the bar and orbits in the spheroids. The amount of angular momentum emitted or absorbed at each resonance depends on the mass distribution, density and spin in the spheroidal components. Thus, …

Celestial Bodies, Rebecca L. Rand, Mark Popinchalk

Capstones

Most of us will never come close to touching space. But space touches us every day. On Celestial Bodies, journalist Rebecca Rand and astronomer Mark Popinchalk explore the ways outer space interacts with life on earth.

In Episode 1, hosts Rebecca Rand and Mark Popinchalk explore how, for millions of years, trees have been recording celestial events in space. Within the rings of their trunks, trees store radiation from solar flares, supernovae, and changes in the earth’s magnetic field. The hosts talk to Dr. Ben Pope to learn more about what we can discover by looking at radioactive molecules …

The High Energy X-Ray Probe (Hex-P): A New Window Into Neutron Star Accretion, R.M. Ludlam, C. Malacaria, E. Sokolova-Lapa, F. Fuerst, P. Pradhan, A.W. Shaw, K. Pottschmidt, S. Pike, G. Vasilopoulos, J. Wilms, J.A. Garcia, K. Madsen, D. Stern, C. Maitra, M. Del Santo, D.J. Walton, M.C. Brumback, J. Van Den Eijnden

Publications

Accreting neutron stars (NSs) represent a unique laboratory for probing the physics of accretion in the presence of strong magnetic fields (B ≳ 10⁸ G). Additionally, the matter inside the NS itself exists in an ultra-dense, cold state that cannot be reproduced in Earth-based laboratories. Hence, observational studies of these objects are a way to probe the most extreme physical regimes. Here we present an overview of the field and discuss the most important outstanding problems related to NS accretion. We show how these open questions regarding accreting NSs in both low-mass and high-mass X-ray binary systems can …

Godel, Escherian Staircase And Possibility Of Quantum Wormhole With Liquid Crystalline Phase Of Iced-Water - Part I: Theoretical Underpinning, Victor Christianto, T. Daniel Chandra, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

As a senior physicist colleague and our friend, Robert N. Boyd, wrote in a journal (JCFA, Vol. 1,. 2, 2022), Our universe is but one page in a large book [4]. For example, things and Beings can travel between Universes, intentionally or unintentionally. In this short remark, we revisit and offer short remark to Neil’s ideas and trying to connect them with geometrization of musical chords as presented by D. Tymoczko and others, then to Escher staircase and then to Jacob’s ladder which seems to point to possibility to interpret Jacob’s vision as described in the ancient book of Genesis …

Godel, Escherian Staircase And Possibility Of Quantum Wormhole With Liquid Crystalline Phase Of Iced-Water - Part Ii: Experiment Description, Victor Christianto, T. Daniel Chandra, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

The present article was partly inspired by G. Pollack’s book, and also Dadoloff, Saxena & Jensen (2010). As a senior physicist colleague and our friend, Robert N. Boyd, wrote in a journal (JCFA, Vol. 1, No. 2, 2022), for example, things and Beings can travel between Universes, intentionally or unintentionally [4]. In this short remark, we revisit and offer short remark to Neil Boyd’s ideas and trying to connect them with geometry of musical chords as presented by D. Tymoczko and others, then to Escherian staircase and then to Jacob’s ladder which seems to pointto possibility to interpret Jacob’s vision …

Improving Inferences About Exoplanet Habitability, Risinie D. Perera, Kevin H. Knuth

Physics Faculty Scholarship

Assessing the habitability of exoplanets (planets orbiting other stars) is of great importance in deciding which planets warrant further careful study. Planets in the habitable zones of stars like our Sun are sufficiently far away from the star so that the light rays from the star can be assumed to be parallel, leading to straightforward analytic models for stellar illumination of the planet’s surface. However, for planets in the close-in habitable zones of dim red dwarf stars, such as the potentially habitable planet orbiting our nearest stellar neighbor, Proxima Centauri, the analytic illumination models based on the parallel ray approximation …