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The Planetary Luminosity Problem: " Missing Planets" And The Observational Consequences Of Episodi Accretion, Sean D. Brittain, Joan R. Najita, Ruobing Dong, Zhaohuan Zhu 2020 Clemson University

The Planetary Luminosity Problem: " Missing Planets" And The Observational Consequences Of Episodi Accretion, Sean D. Brittain, Joan R. Najita, Ruobing Dong, Zhaohuan Zhu

Physics & Astronomy Faculty Publications

The high occurrence rates of spiral arms and large central clearings in protoplanetary disks, if interpreted as signposts of giant planets, indicate that gas giants commonly form as companions to young stars (Myr) at orbital separations of 10–300 au. However, attempts to directly image this giant planet population as companions to more mature stars (>10 Myr) have yielded few successes. This discrepancy could be explained if most giant planets form by "cold start," i.e., by radiating away much of their formation energy as they assemble their mass, rendering them faint enough to elude detection at later times. In ...


Computational Astronomy: Classification Of Celestial Spectra Using Machine Learning Techniques, Gayatri Milind Hungund 2020 San Jose State University

Computational Astronomy: Classification Of Celestial Spectra Using Machine Learning Techniques, Gayatri Milind Hungund

Master's Projects

Lightyears beyond the Planet Earth there exist plenty of unknown and unexplored stars and Galaxies that need to be studied in order to support the Big Bang Theory and also make important astronomical discoveries in quest of knowing the unknown. Sophisticated devices and high-power computational resources are now deployed to make a positive effort towards data gathering and analysis. These devices produce massive amount of data from the astronomical surveys and the data is usually in terabytes or petabytes. It is exhaustive to process this data and determine the findings in short period of time. Many details can be missed ...


A Fast Radio Burst Discovered In Fast Drift Scan Survey, Weiwei Zhu, Di Li, Rui Luo, Chenchen Miao, Bing Zhang, Laura Spitler, Duncan Lorimer, Michael Kramer, David Champion, Youling Yue, Andrew Cameron, Marilyn Cruces, Ran Duan, Yi Feng, Jun Han, George Hobbs, Chenhui Niu, Jiarui Niu, Zhichen Pan, Lei Qian, Dai Shi, Ningyu Tang, Pei Wang, Hongfeng Wang, Mao Yuan, Lei Zhang, Xinxin Zhang, Shuyun Cao, Li Feng, Hengqian Gan, Long Gao 2020 Chinese Academy of Sciences

A Fast Radio Burst Discovered In Fast Drift Scan Survey, Weiwei Zhu, Di Li, Rui Luo, Chenchen Miao, Bing Zhang, Laura Spitler, Duncan Lorimer, Michael Kramer, David Champion, Youling Yue, Andrew Cameron, Marilyn Cruces, Ran Duan, Yi Feng, Jun Han, George Hobbs, Chenhui Niu, Jiarui Niu, Zhichen Pan, Lei Qian, Dai Shi, Ningyu Tang, Pei Wang, Hongfeng Wang, Mao Yuan, Lei Zhang, Xinxin Zhang, Shuyun Cao, Li Feng, Hengqian Gan, Long Gao

Physics & Astronomy Faculty Publications

We report the discovery of a highly dispersed fast radio burst (FRB), FRB 181123, from an analysis of ~1500 hr of drift scan survey data taken using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The pulse has three distinct emission components, which vary with frequency across our 1.0–1.5 GHz observing band. We measure the peak flux density to be... (See full abstract in article).


Transport In Neutron Star Mergers, Steven Patrick Harris 2020 Washington University in St. Louis

Transport In Neutron Star Mergers, Steven Patrick Harris

Arts & Sciences Electronic Theses and Dissertations

Neutron star mergers are the only situation in nature in which we find matter compressed to several times nuclear saturation density and temperatures of several tens of MeV. By observing and numerically simulating neutron star mergers, we can learn about the nature of matter at high temperatures and densities. Neutron star merger simulations evolve Einstein's equations of general relativity coupled to the equations of relativistic hydrodynamics along with a nuclear equation of state, which describes the neutron star matter. Many simulations also take into account neutrino transport and electrodynamics. The purpose of this thesis is to see whether other ...


Cherenkov Gamma Ray Detectors On High-Energy-Density Systems, Kevin Daniel Meaney 2020 University of New Mexico

Cherenkov Gamma Ray Detectors On High-Energy-Density Systems, Kevin Daniel Meaney

Physics & Astronomy ETDs

High energy density (HED) systems are some of the most extreme environments ever created by mankind. Systems with pressures greater than 1 MBar can only be created by a handful of devices on earth, often utilizing high intensity lasers or pulsed power machines. HED systems offer a view into an extreme form of matter only seen in stellar cores, supernovas and other powerful astrophysical systems. Creating HED systems on Earth offer the possibility, if the physics and technology can be matured, to one day create a fusion power plant. If a system is hot and dense enough, the fusion reaction ...


Supertiger Elemental Abundances For The Charge Range $41 \Leq Z \Leq 56$, Nathan Elliot Walsh 2020 Washington University in St. Louis

Supertiger Elemental Abundances For The Charge Range $41 \Leq Z \Leq 56$, Nathan Elliot Walsh

Arts & Sciences Electronic Theses and Dissertations

No abstract provided.


Supercdms: Energy Calibration Of A Ge Hv Particle Detector, Salamong Xiong, Vuk Mandic, Matthew Fritts, Nicholas Mast, Jacob Nelson 2020 Macalester College

Supercdms: Energy Calibration Of A Ge Hv Particle Detector, Salamong Xiong, Vuk Mandic, Matthew Fritts, Nicholas Mast, Jacob Nelson

Macalester Journal of Physics and Astronomy

The goal of the SuperCDMS collaboration is to directly detect dark matter. Weakly Interacting Massive Particles (WIMPs) are potential candidates. To detect WIMPs, it is important to be able to predict how a Ge/Si particle detector will respond to a dark matter signal. In particular, it is necessary to calibrate the recoil energy measured by these detectors. This paper presents evidence for dark matter, a description of the detector operation, and procedures used to analyze measured data from a SuperCDMS-HV Ge particle detector using Am-241 and a PuBe neutron source. Due to high event rate, criteria were developed to ...


The Leoncino Dwarf: A Neutral Hydrogen Analysis Of Agc 198691 And Its Extremely Metal-Poor Environment, Tylyn Page 2020 Macalester College

The Leoncino Dwarf: A Neutral Hydrogen Analysis Of Agc 198691 And Its Extremely Metal-Poor Environment, Tylyn Page

Macalester Journal of Physics and Astronomy

Studies of low-mass galaxies are important for populating the low-mass ends of funda- mental physical relations. Extremely metal-poor (XMP) galaxies are low-mass galaxies with gas-phase oxygen abundances of 12+log(O/H) ≤ 7.35 ( 1/20 Z⊙), and are especially interesting as proxies for studying the distant past, as their chemical makeup resembles those of galaxies in the early universe. AGC 198691, referred to as the Leoncino Dwarf, was discovered through the Arecibo Legacy Fast ALFA (ALFALFA) survey and found to have an oxygen abundance of less than 3% Z⊙. Presented here are the results of recent Karl G. Jansky ...


Large Scale Grid Integration Of Wind And Solar Power With Storage, Nicholas Moore 2020 Macalester College

Large Scale Grid Integration Of Wind And Solar Power With Storage, Nicholas Moore

Macalester Journal of Physics and Astronomy

The current energy grid in the United States is dominated by carbon intense energy generation methods that are based on production when and where it is required. However, solar and wind power have proved themselves as the most promising carbon free energy generation sources. Due to the unpredictable and uncontrollable nature of energy production from solar and wind, large scale integration of these resources into the electric grid will require robust storage capacity. In this project, we model the energy grid of the Midcontinent Independent System Operator (MISO) energy region with high concentrations of solar and wind power to analyze ...


Probing The Magnetic Fields In Cosmic Web Filaments, Andrew L. Mizener 2020 Macalester College

Probing The Magnetic Fields In Cosmic Web Filaments, Andrew L. Mizener

Macalester Journal of Physics and Astronomy

We present a project to constrain the properties of magnetic fields in Cosmic Web filaments. We first perform rotation measure (RM) synthesis on 24 S-band Karl G Jansky Very Large Array (VLA) observations of moderate-redshift active galactic nuclei (AGN). These observations are combined with an existing catalog of Cosmic Web filaments in order to determine the number of filaments a given sight-line passes near or through. By tracking how observables such as rotation measure and polarization fraction change as a function of the number of intervening cosmic web filaments, we take the first steps towards providing observational constraints on the ...


Shape Model Of Potentially Hazardous Asteroid 1981 Midas From Radar And Lightcurve Observations, Riley McGlasson 2020 Macalester College

Shape Model Of Potentially Hazardous Asteroid 1981 Midas From Radar And Lightcurve Observations, Riley Mcglasson

Macalester Journal of Physics and Astronomy

We report observations of potentially hazardous, Apollo-class asteroid 1981 Midas, which passed 0.090 au from Earth (35 lunar distances) on March 21, 2018. During this close approach, Midas was observed by radar both from the Arecibo Observatory on March 21 through 25 (five nights), and from NASA's Goldstone Deep Space Communications Complex on March 19 and 21. These radar observations yielded one-dimensional continuous-wave spectra and two-dimensional delay-Doppler images. In addition, there have been optical lightcurve observations of Midas during four apparitions (1987, 1992, 2004, and 2018), which showed a rotation period of 5.22 hours. Midas has an ...


A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan 2020 Macalester College

A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan

Macalester Journal of Physics and Astronomy

We present observations from two separate methods for observing the Galactic Center in an attempt to characterize its pulsar and neutron star populations. A persistent puzzle of the past 20 years has been the lack of pulsar detections towards the Galactic Center, specifically within a few parsecs of the central supermassive black hole Sgr A*. This object is bright in the total intensity of its polarized emission, but is very weakly linearly polarized. We take advantage of these circumstances in an experimental search technique where we utilize the Faraday effect in an attempt to detect high rotation measure (RM) point ...


Modeling Scavenging For A Hydraulic Free-Piston Engine, Nathan Davies 2020 Macalester College

Modeling Scavenging For A Hydraulic Free-Piston Engine, Nathan Davies

Macalester Journal of Physics and Astronomy

The hydraulic free-piston engine at the University of Minnesota offers a solution to improve the hydraulic efficiency and reduce emission output of off-road vehicles. We developed a MATLAB Simulink model to track the pressure, temperature, and mass profile of the fuel within the cylinder during operation. By varying different initial conditions of our model, we found that a higher intake manifold pressure and larger bottom dead center location results in higher scavenging efficiency. These results can be used to improve the controller of this engine and better maintain stable operation.


Band Extension And Possible Ridge Compression On Europa, Sarah Chinski 2020 Macalester College

Band Extension And Possible Ridge Compression On Europa, Sarah Chinski

Macalester Journal of Physics and Astronomy

Jupiter's icy moon Europa has captivated and perplexed the scientific community since the discovery of its global liquid water ocean. Over the course of several missions to the Jovian system, high-resolution observations of Europa have determined that there are spreading zones where new crust is created, similar to the mid-ocean spreading tectonic process we observe on Earth. These features, known as bands, have symmetric hills and valleys, indicating brief events of activity where material from the interior is exuded through a central crack, and solidifies on both sides, creating two positive topography. Recently, Europan scientists have been questioning how ...


Electrical Measurement Of Sram Cell Variation And Sensitivity To Singe-Event Upsets By Low-Energy Protons, James M. Cannon 2020 Macalester College

Electrical Measurement Of Sram Cell Variation And Sensitivity To Singe-Event Upsets By Low-Energy Protons, James M. Cannon

Macalester Journal of Physics and Astronomy

With the rise of the transistor in the 1970s, electronics shifted from analog circuitry, where values are stored on a continuum, to digital, in which ones and zeros are the law of the land. Transistors, as a class circuit element, can be affected by radiation and cosmic rays which then cause temporary or permanent failures, depending on the specifics of the situation. On Earth, this poses little risk with all electronics shielded by the magnetosphere, however for space bound electronics, the risks from these extraterrestrial particles are not so negligible. The first step in designing a mission to be able ...


Design And Modal Analysis Of An Ultra-Wideband Receiver For Green Bank Observatory, Alyssa Bulatek 2020 Macalester College

Design And Modal Analysis Of An Ultra-Wideband Receiver For Green Bank Observatory, Alyssa Bulatek

Macalester Journal of Physics and Astronomy

The next generation of radio receivers for astronomy will be marked by tenfold improvements in sensitivity. These sensitive receivers will be useful for the detection of broadband fast radio bursts and other transients as well as the efficient discovery of radio recombination lines among many other scientific pursuits. One contribution to these improvements is an increase to decade receiver bandwidths. The Green Bank Observatory (GBO) is currently in the process of fabricating a new ultra-wideband (UWB; 0.7 to 4.2 GHz) receiver for the Green Bank Telescope (GBT). The UWB receiver will be used by the North American Nanohertz ...


Alfalfa Harvest: Hi Imaging And 3d Modeling Of Candidate Local Group Dwarf Galaxies, Lilly Bralts-Kelly, Susie Paine, Elizabeth A. K. Adams, John M. Cannon 2020 Macalester College

Alfalfa Harvest: Hi Imaging And 3d Modeling Of Candidate Local Group Dwarf Galaxies, Lilly Bralts-Kelly, Susie Paine, Elizabeth A. K. Adams, John M. Cannon

Macalester Journal of Physics and Astronomy

Isolated neutral hydrogen (HI) clouds, or "ultra-compact high-velocity clouds" (UCHVCs), form a small subset of detections by the Arecibo Legacy Fast ALFA (ALFALFA) blind extragalactic survey. These systems, if located within ~1 Mpc, would populate the lowest-mass end of the HI mass function. Subsequent optical imaging has revealed that some of these UCHVCs harbor associated (thought sparse) stellar populations, suggesting that they may be some of the most extreme galaxies known in the Local Volume, with properties akin to ultra-faint dwarf galaxies but with significant neutral gas reservoirs. In this work, we investigate the neutral hydrogen properties of six UCHVC ...


Leoncino And Ugc 5186, Josh Bartz 2020 Macalester College

Leoncino And Ugc 5186, Josh Bartz

Macalester Journal of Physics and Astronomy

AGC 198691 is commonly known as the Leoncino Dwarf and is one of the most metal poor galax- ies known. An Arecibo observation in 2011 first suggested that Leoncino could be gravitationally interacting with its neighbor UGC 5186. In this paper new VLA data is used to examine the H I com- ponent of both galaxies to determine their gravitational relationship. Although the VLA could not confirm intragalactic gas seen by Aricebo, the H I density and velocity components are strong indirect evidence of gravitational interaction. UGC 5186 has a large gaseous arm reaching in the direction of Leoncino. Additionally ...


Congressional Committee Resources On Space Policy During The 115th Congress (2017-2018): Providing Context And Insight Into Us Government Space Policy, Bert Chapman 2020 Purdue University

Congressional Committee Resources On Space Policy During The 115th Congress (2017-2018): Providing Context And Insight Into Us Government Space Policy, Bert Chapman

Libraries Faculty and Staff Presentations

Article 1 of the US Constitution assigns the US Congress numerous responsibilities. These include creating new laws, revising existing laws, funding government programs, and conducting oversight of these programs' performance. Oversight of US Government agency space policy programs is executed by various congressional space policy committees including the House and Senate Science Committees, Armed Services, and Appropriations Committees. These committees conduct many public hearings on space policy, which invite expert witnesses to testify on US space policy programs and feature debate on the strengths and weaknesses of these programs. Documentation produced by these committees is widely available to the public ...


Water On Mars—A Literature Review, Mohammad Nazari-Sharabian, Mohammad Aghababei, Moses Karakouzian, Mehrdad Karami 2020 University of Nevada, Las Vegas

Water On Mars—A Literature Review, Mohammad Nazari-Sharabian, Mohammad Aghababei, Moses Karakouzian, Mehrdad Karami

Civil & Environmental Engineering and Construction Faculty Publications

To assess Mars’ potential for both harboring life and providing useable resources for future human exploration, it is of paramount importance to comprehend the water situation on the planet. Therefore, studies have been conducted to determine any evidence of past or present water existence on Mars. While the presence of abundant water on Mars very early in its history is widely accepted, on its modern form, only a fraction of this water can be found, as either ice or locked into the structure of Mars’ plentiful water-rich materials. Water on the planet is evaluated through various evidence such as rocks ...


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