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Rotation Lightcurves Of Small Jovian Trojan Asteroids, Linda French, Robert D. Stephens, Daniel Coley, Lawrence H. Wasserman, Jennifer Sieben 2015 Illinois Wesleyan University

Rotation Lightcurves Of Small Jovian Trojan Asteroids, Linda French, Robert D. Stephens, Daniel Coley, Lawrence H. Wasserman, Jennifer Sieben

Linda French

Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and Jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We present new lightcurve information for 19 Trojans ≲ 30 km in diameter, more than doubling the number of objects in this size range for which some rotation information is known. The minimum densities for objects with complete lightcurves are estimated and are found to be comparable to those measured for cometary nuclei. A significant fraction (~40%) of this observed small Trojan population rotates slowly (P > 24 hours ...


Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa 2015 Iowa State University

Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa

2015 Academic High Altitude Conference

Since the time of Victor Hess and his balloon flight that demonstrated that cosmic rays increased with altitude, new detection methods have become widely available to be used on current day flights. One such method is to utilize CCDs with long duration exposures. During the exposures the CCD is exposed to cosmic rays which then leave a track. This phenomenon is caused by the CCD's inability to distinguish between photons of light and charged particles. Such tracks can then be separated from the CCD's background noise and classified.


Directional Camera Control On High Altitude Balloons, Matthew M. Plewa, Brent Scharlau 2015 Iowa State University

Directional Camera Control On High Altitude Balloons, Matthew M. Plewa, Brent Scharlau

2015 Academic High Altitude Conference

The research reported in this paper examined the design and control of a gimbal for solar eclipse tracking and video recording. The gimbal design required 3 axes of rotation to allow for full range of motion. Utilizing individual brushless motors for each of the axes ensure minimum rotational requirements on each axes. In controlling the gimbal, both a mathematical and visual method were utilized. The mathematical method is a modified version of what is currently used for solar array pointing. The visual method looks at where the position of the sun is within the image and determines what angle changes ...


Cosmic Ray Air Shower Lateral Coincidences, Gordon C. McIntosh 2015 University of Minnesota, Morris

Cosmic Ray Air Shower Lateral Coincidences, Gordon C. Mcintosh

2015 Academic High Altitude Conference

At the University of Minnesota, Morris, my students and I have begun to investigate the time and altitude dependence of air showers. Air showers are cosmic ray secondaries that spread out laterally around the primary cosmic ray direction. To investigate the air showers we have been measuring the lateral coincidences among three Aware RM60 Geiger counters located at 0 cm, 15 cm, and 40 cm. Most of these measurements have been carried out at the surface. The rate of lateral, triple coincidences of Geiger counter with this configuration is 0.053 ±0.013 hr-1 at the surface. On 4 ...


Models Of Time Travel And Their Consequences, Antonio M. Mantica 2015 Oglethorpe University

Models Of Time Travel And Their Consequences, Antonio M. Mantica

Oglethorpe Journal of Undergraduate Research

How do we travel through time? We know that we can move forward in it (we have no choice), but can we jump forward in time? Can we go backward in time? It also gives rise to other troubling questions: is time measurable in distinct increments, or does it flow continuously? In "Models of Time Travel and their Consequences," Antonio Mantica walks the reader through current understandings of how time functions in Einstein's universe and proposes three distinct models to explain it. Following that, he provides a list of experiments to credit or discredit the models. Appropriate for audiences ...


Optimization Of A Solar Simulator For Planetary-Photochemical Studies, Et-touhami Es-sebbar, Yves Bénilan, Nicolas Fray, Hervé Cottin, Antoine Jolly, Marie-Claire Gazeau 2015 University of Paris 11, Orsay

Optimization Of A Solar Simulator For Planetary-Photochemical Studies, Et-Touhami Es-Sebbar, Yves Bénilan, Nicolas Fray, Hervé Cottin, Antoine Jolly, Marie-Claire Gazeau

Dr. Et-touhami Es-sebbar

Low-temperature microwave-powered plasma based on hydrogen and hydrogen with noble gas mixtures are widely used as a continuous vacuum ultraviolet (VUV) source in laboratory experiments carried out to mimic the photochemistry in astrophysical environments. In this work, we present a study dedicated to optimizing such sources in terms of mono-chromaticity at Lyα (H(Lyα) line at 121.6 nm ~ 10.2 eV) and high spectral irradiance. We report the influence on the emission spectrum of a wide range of experimental conditions including gas composition (pure H2, pure He, and H2/He mixture), gas pressure, flow rates, and microwave power. The ...


Determining The Relationship Between The [Oiii] 5007 Å Emission Line Profile And The Stellar Velocity Dispersion In Active Galaxies, Nathaniel Milgram 2015 California Polytechnic State University - San Luis Obispo

Determining The Relationship Between The [Oiii] 5007 Å Emission Line Profile And The Stellar Velocity Dispersion In Active Galaxies, Nathaniel Milgram

Physics

The empirical relation between the stellar velocity dispersion (SVD) of the bulge and the mass of the central supermassive black hole (BH) suggests a link between host galaxy and BH evolution. For active galactic nuclei (AGNs), the BH mass (MBH) can be estimated in a straightforward way from the Doppler broadening of the broad emission lines using the so-called virial method. However, the powerful AGN continuum emission often outshines the underlying stellar absorption lines, making it difficult to measure SVD of the host galaxy. Thus, the MBH - SVD relation is difficult to establish for galaxies containing AGNs. As a remedy ...


Frequency Of Seyfert Type Transitions In A Sample Of 102 Local Active Galactic Nuclei, Jordan Runco 2015 California Polytechnic State University - San Luis Obispo

Frequency Of Seyfert Type Transitions In A Sample Of 102 Local Active Galactic Nuclei, Jordan Runco

Physics

A sample of ∼100 type-1 local (0.02 ≤ z ≤ 0.1) active galaxies (AGNs) was selected from the Sloan Digital Sky Survey with black hole masses MBH > 107 Mʘ and re-observed using the Keck 10-m telescope to study the local scaling relations between MBH and the host galaxy properties. As a side product, the data provides insight into any changes of the broad-line region within the 3-9 year time-frame covered by the two sets of spectra. The variability of the broad Hβ emission line is of particular interest to us, not only because it is used ...


Analysis And Comparison Of Physical Properties And Morphology Of Impact Melt Flows On Venus And The Moon To Determine Atmospheric Controls, Christine Elizabeth Dong 2015 Bates College

Analysis And Comparison Of Physical Properties And Morphology Of Impact Melt Flows On Venus And The Moon To Determine Atmospheric Controls, Christine Elizabeth Dong

Geology Theses

Impact melt flows form when target material melted by an impact breaches the rim of the impact crater. The melt flows out and away from the crater, forming a lava flow. Such flows have been identified on Venus and the Moon by previous studies. This study aims to document impact melt flows on these two bodies to determine the differences, if any, between them, and to ascertain whether these differences are due to atmospheric conditions. Previously recorded morphological data from Robert Herrick of the Lunar and Planetary Institute and Neish et al. (2014) are used in conjunction with S-band (12 ...


Defining The Circumstellar Habitable Zone, Blake Cervetti, Joanna McCall 2015 DePaul University

Defining The Circumstellar Habitable Zone, Blake Cervetti, Joanna Mccall

DePaul Discoveries

The study of habitable exoplanets is a rapidly expanding field in astronomy. Exoplanets are planets that orbit stars other than our own sun. One of the keys to knowing whether or not an exoplanet is habitable is by studying the circumstellar habitable zone, or CHZ. Over the past several years, the defined limits of the CHZ have become susceptible to change as new parameters and factors are found to affect a planets habitability. There are many factors that affect its habitability, including the composition of the star, the mass of the planet, the planets atmosphere, etc. Our focus is divided ...


Detection Of Baryonic Acoustic Oscillations In The Matter Power Spectrum, Spencer Everett, Ian Johnson, Jon Murphy, Mary Tarpley 2015 DePaul University

Detection Of Baryonic Acoustic Oscillations In The Matter Power Spectrum, Spencer Everett, Ian Johnson, Jon Murphy, Mary Tarpley

DePaul Discoveries

Using the spectra of 22,923 high-redshift quasars from the Baryon Oscillation Spectrosocpic Survey (BOSS) subset of the Sloan Digital Sky Survey (SDSS), the authors detect evidence of the primordial baryonic acoustic oscillations (BAOs) in the matter power spectrum. The detection further endorses the currently accepted Lambda-CDM model of cosmology based upon the existence of dark energy (Lambda) and cold dark matter (CDM). Additionally, the use of the continuous wavelet transform to calculate the power spectrum has many advantages over traditional Fourier methods and independently corroborates previous detections.


Multidimensional Simulations Of Non-Linear Cosmic Ray Production In Supernova Remnant Evolution, Joshua Wood 2015 Clemson University

Multidimensional Simulations Of Non-Linear Cosmic Ray Production In Supernova Remnant Evolution, Joshua Wood

All Dissertations

When a high-mass star (& 4Msun) explodes at the end of its life, a supernova occurs, leaving its degenerate core and a fast-moving shell of matter, known as a supernova remnant (SNR). The SNR shell lasts for many thousands of years, generating emissions from low-frequency radio (~ 10-7 eV) up to γ-ray regime (~ 1015 eV). It is also believed that SNRs are the predominant source of galactic cosmic rays, accelerating a population of thermal ions, primarily protons, up to relativistic energies by means of the diffusive shock acceleration (DSA) mechanism. The small population of thermal (Boltzmann) particles, p ~ 10-3 eV, that are accelerated to relativistic energies, p ~ 1015 eV, extract a significant amount of energy from the SNR shell. The existence of a small but highly energetic population of non-thermal particles feeds back into the dynamic evolution of the SNR, which, in turn, affects the production of new particles and the continued acceleration of particles already swept up in the shock. Much research has been done in investigating the case of particles accelerated in spherically symmetric SNRs; we present here the first simulations of supernova remnant evolution with nonlinear cosmic ray feedback in multiple dimensions. The research here presents a new approach to an old problem, allowing for a deeper investigation into the role of cosmic ray production in supernova remnant environments. The findings here show that, at the early stages of SNR evolution, the presence of cosmic rays in the shocks modifies the growth of hydrodynamic instabilities; severely damping the Rayleigh-Taylor instabilities in particular. We also find that the young remnant produces a strong TeV population of CRs that can generate TeV ...


A Photometric Study Of The Eclipsing Binary Star Uv Lyncis, Edward J. Michaels 2015 Stephen F Austin State University, Department of Physics and Astronomy

A Photometric Study Of The Eclipsing Binary Star Uv Lyncis, Edward J. Michaels

Bright Ideas Conference

UV Lyncis is a short period, over contact eclipsing binary star. These stars are physically in contact with each other, sharing a common atmosphere. Photometric observations were made on 10 nights in February and March 2014 using the 0.3 meter robotic telescope and a CCD science imager at the Waffelow Creek Observatory. 3051 images were acquired, calibrated and then reduced to record the changing brightness as the two stars orbited and eclipsed each other. Data collected resulted in complete light curves in 5 band passes and several times of minima. A period analysis confirmed previous studies that the orbital ...


Time-Dependent Photoionization Modeling Of Gaseous Nebulae, Manuel Bautista, Ehab ElHoussieny, Javier Garcia, T. R. Kallman 2015 Western Michigan University

Time-Dependent Photoionization Modeling Of Gaseous Nebulae, Manuel Bautista, Ehab Elhoussieny, Javier Garcia, T. R. Kallman

Faculty Research and Creative Activities Award (FRACAA) Recipients

Photoionized plasmas are the most commonly observed in astronomy, particularly through optical and UV observatories, such as the Hubble Space Telescope (HST). Modeling astronomical photoionized plasmas is generally done from the condition of steady-state statistical equilibrium, but none-equilibrium time-dependent photoionization (TDP) is found in a large variety of astronomical objects, yet it has received little attention thus far. There are multiple examples of notable failures of steady-state photoionization modeling. We have developed of a general purpose time-dependent photoionization modeling code and its use in the analysis of astronomical spectra. The new code, TDPX, is capable of including all chemical elements ...


Stellar Spectroscopy: New Methods And Insights, Sanaz S. Golriz 2015 The University of Western Ontario

Stellar Spectroscopy: New Methods And Insights, Sanaz S. Golriz

University of Western Ontario - Electronic Thesis and Dissertation Repository

The study of the chemical evolution of stars is of crucial importance since they play a major role in the enrichment of the chemistry of the universe. Throughout their lifetime, stars undergo several processes that can alter their chemistry. Gradually, the nucleosynthesis products from the interior of the star are radiatively and convectively levitated and mixed with the upper layers of the atmosphere. In the later stages of their evolution, low to intermediate mass stars (0.8-8.0~M☉) eject a significant fraction of these nucleosynthesis products, resulting in a circumstellar envelope of gas and dust around the central star ...


Supernatural Cosmic Origins: Challenging The Reigning Paradigm, Rachel Blattner 2015 Liberty University

Supernatural Cosmic Origins: Challenging The Reigning Paradigm, Rachel Blattner

Senior Honors Theses

Contemporary scientific study primarily uses a paradigm based upon naturalism, materialism, and empiricism on which to base research. The widely accepted cosmological model the big bang theory adheres to this paradigm. Despite many weaknesses in this model and in the paradigm itself, researchers continue to favor the modification of the accepted model over the adoption of other more comprehensive models. The paradigm from which the models proposed by Russell Humphries, John Hartnett, and Jason Lisle come justifies the six-day creation young-earth biblical account and better fits observational evidence with fewer arbitrary assumptions than the paradigm from which the big bang ...


The Ptolemaic System: A Detailed Synopsis, John Cramer Dr. 2015 Kennesaw State University

The Ptolemaic System: A Detailed Synopsis, John Cramer Dr.

Oglethorpe Journal of Undergraduate Research

The Ptolemaic System, constructed by Claudius Ptolemeus (the Latin form of his name), was the most influential of all Earth centered cosmological systems. His ingenious and creative work is primarily recorded in his book The Mathematical Systematic Treatise which the Arabs characterized as “the greatest” and, in so doing, gave the book its most used name, Almagest.


The Copernican System: A Detailed Synopsis, John Cramer Dr. 2015 Kennesaw State University

The Copernican System: A Detailed Synopsis, John Cramer Dr.

Oglethorpe Journal of Undergraduate Research

Dissatisfied with the problems of the geocentric system inherited from Claudius Ptolemy, Nicholas Copernicus began the change from geocentrism to heliocentrism. His eponymous system was expounded first in the Commentariolus (written about 1508 and circulated privately in manuscript form) and then more fully and finally in his book, De Revolutionibus Orbium Coelestium (On the Revolutions of the Celestial Orbs) published as he lay dying in 1543.


Methods And Results Toward Measuring Magnetic Fields In Star-Forming Regions, Scott C. Jones 2015 The University of Western Ontario

Protolunar Disk Evolution And The Depletion Of Volatile Elements In The Moon, Robin M. Canup, Channon Visscher, Julien Salmon, Bruce Fegley Jr. 2015 Southwest Research Institute

Protolunar Disk Evolution And The Depletion Of Volatile Elements In The Moon, Robin M. Canup, Channon Visscher, Julien Salmon, Bruce Fegley Jr.

Faculty Work: Comprehensive List

We explore how the evolution of the protolunar disk could lead to a depletion in K, Na, and Zn in the Moon relative to Earth even in the absence of escape.


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