Variability Of Mars' Seasonal North Polar Cap, 2016 Gordon State College
Variability Of Mars' Seasonal North Polar Cap, Richard W. Schmude Jr.
Georgia Journal of Science
Mars’ seasonal north polar cap (hereafter sNPC) underwent year-to-year changes between 2008 and 2015 or Mars years 29–33. The writer monitored changes in the sNPC using images made with the MARCI camera onboard the Mars Reconnaissance Orbiter (MRO). Nine isolated bright spots corresponding to Korolev, Lomonosov, and Louth Craters, the albedo features Ierne, Olympia (or Lemuria), and Cecropia, and three unnamed features were examined. The following was concluded: 1) the sNPC underwent small year-to-year changes between 2008 and 2015 [MY = 29–33], 2) there are no years where all temporary frost features lasted longer than their mean lifespan, and ...
Aging Comets And Their Meteor Showers, 2016 The University of Western Ontario
Aging Comets And Their Meteor Showers, Quanzhi Ye
Electronic Thesis and Dissertation Repository
Comets are thought to be responsible for the terrestrial accretion of water and organic materials. Comets evolve very quickly, and will generally deplete their volatiles in a few hundred revolutions. This process, or the aging of comets, is one of the most critical yet poorly understood problems in planetary astronomy. The goal of this thesis is to better understand this problem by examining different parts of the cometary aging spectrum of Jupiter-family comets (JFCs), a group of comets that dominates the cometary influx in the near-Earth space, using both telescopic and meteor observations. We examine two representative JFCs and the ...
Back Half Of The Year, 2016 Gettysburg College
Back Half Of The Year, Ian R. Clarke
Physics and Astronomy Faculty Publications
Here we are in the back half of 2016, and the days are getting shorter. We have, as of today, lost 18 minutes since the solstice on June 20, and the speed of that change is quickening. You may wonder why it is that we have our hottest weather after our longest day is behind us. The simple answer is that it takes time for land and water masses to warm up. That’s the reason that Sept. 21 is likely to be a lot warmer than March 21, even though they have the same amount of daylight. [excerpt]
Living In The Milky Way, 2016 Gettysburg College
Living In The Milky Way, Ian R. Clarke
Physics and Astronomy Faculty Publications
It’s finally here. Today, June 20 at 6:34 p.m., is the the summer solstice, also known as the first day of summer and, confusingly enough, midsummer’s eve. From a scientific perspective, it marks the moment the sun reaches its northernmost point in our sky. As a result of that position, it’s the shortest night and longest day if you live north of the equator. [excerpt]
Exploring The Early Solar System With Cometary Gases: Observations Of Spontaneous Activity Around Comet 67p/Churyumov-Gerasimenko Post-Perihelion With The R-Alice Ultraviolet Spectrograph, 2016 University of Colorado, Boulder
Exploring The Early Solar System With Cometary Gases: Observations Of Spontaneous Activity Around Comet 67p/Churyumov-Gerasimenko Post-Perihelion With The R-Alice Ultraviolet Spectrograph, John W. Noonan
Undergraduate Honors Theses
The Rosetta Alice (R-Alice) ultraviolet spectrograph on the European Space Agency Rosetta spacecraft, currently escorting the comet 67P/Churyumov-Gerasimenko in its orbit around the Sun, has observed the activity of the comet since encounter in August 2014. Fortuitous observations taken in October and November 2015, two and three months after perihelion respectively, show large increases in the Lyman-Beta, OI 1304, CII 1335, OI] 1356, and CI 1657 atomic emission lines that indicate gas outbursts. Due to the electron impact on gases in the cometary coma the data is compared to measured cross sections and line ratios to put constraints on ...
Pre-Mission Input Requirements To Enable Successful Sample Collection By A Remote Field/Eva Team, 2015 NASA Marshall Space Flight Center
Pre-Mission Input Requirements To Enable Successful Sample Collection By A Remote Field/Eva Team, Barbara A. Cohen, Darlene S. S. Lim, Kelsey E. Young, Anna Brunner, Richard C. Elphic, Audrey Horne, Mary C. Kerrigan, Gordon O. Osinski, John R. Skok, Steven W. Squyres, David Saint-Jacques, Jennifer L. Heldmann
Journal of Human Performance in Extreme Environments
We used a field excursion to the West Clearwater Lake Impact structure as an opportunity to test factors that contribute to the decisions a remote field team (for example, astronauts conducting extravehicular activities (EVA) on planetary surfaces) makes while collecting samples for return to Earth. We found that detailed background on the analytical purpose of the samples, provided to the field team, enables them to identify and collect samples that meet specific analytical objectives. However, such samples are not always identifiable during field reconnaissance activities, and may only be recognized after outcrop characterization and interpretation by crew and/or science ...
Solar Modulation Of The Cosmic Ray Intensity And The Measurement Of The Cerenkov Reemission In Nova’S Liquid Scintillator, 2015 University of Tennessee - Knoxville
Solar Modulation Of The Cosmic Ray Intensity And The Measurement Of The Cerenkov Reemission In Nova’S Liquid Scintillator, Philip James Mason
The NOνA (NuMI Off-axis electron neutrino Appearance) experiment is a long baseline neutrino oscillation experiment at Fermi National Accelerator Laboratory. Its purpose is to observe the oscillation of νμ (muon neutrino) to νe (electron neutrino) and to investigate the neutrino mass hierarchy and CP violation in the neutrino sector. Two detectors have been built for this purpose, a Near Detector 300 feet underground at Fermilab, and a Far Detector, on the surface at Ash River, Minnesota.
The completion of NOνA’s Far Detector in October 2014 enabled not only the recent measurement of neutrino oscillations, but an array ...
New Benzene Absorption Cross Sections In The Vuv, Relevance For Titan’S, 2015 Paul Scherrer Institute (PSI)
New Benzene Absorption Cross Sections In The Vuv, Relevance For Titan’S, Fernando J. Capalbo, Yves Bénilan, Nicolas Fray, Martin Schwell, Norbert Champion, Et-Touhami Es-Sebbar, Tommi T. Koskinen, Ivan Lehocki, Roger V. Yelle
Dr. Et-touhami Es-sebbar
Benzene is an important molecule in Titan’s atmosphere because it is a potential link between the gas phase and the organic solid phase. We measured photoabsorption in the ultraviolet by benzene gas at temperatures covering the range from room temperature to 215 K. We derived benzene absorption cross sections and analyzed them in terms of the transitions observed. No significant variation with measurement temperature was observed. We discuss the implications of our measurements for the derivation of benzene abundance profiles in Titan’s thermosphere, by the Cassini/Ultraviolet Imaging Spectrograph (UVIS). The use of absorption cross sections at low ...
Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, 2015 Los Alamos National Laboratory
Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, P. Pilleri, Daniel B. Reisenfeld, T. H. Zurbuchen, S. T. Lepri, P. Shearer, J. A. Gilbert, R. Von Steiger, R. C. Wiens
Physics and Astronomy Faculty Publications
We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009), and the period in which the Genesis spacecraft was collecting SW (late 2001-early 2004). We differentiate our analysis in terms in SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that ...
Low Intensity Gamma-Ray Spectroscopy Of The Lake Labyrinth Meteorite, 2015 California Polytechnic State University - San Luis Obispo
Low Intensity Gamma-Ray Spectroscopy Of The Lake Labyrinth Meteorite, Tristan C. Paul
A 23.7g fragment of the Lake Labyrinth Meteorite (fell in 1924, collected in 1934 at Lake Labyrinth in South Australia, Australia) was re-investigated for evidence of the presence of 98Tc using a two dimensional low-intensity gamma-ray spectrometer. A new calibration technique using 26Al sources found the gamma-rays previously thought to be due to 98Tc are more likely from 166Ho. The presence of 166Ho is most likely due to activation of the stable 165Ho in the meteorite from terrestrial background sources where it was stored.
Photometric Trends In The Visible Solar Continuum And Their Sensitivity To The Center-To-Limb Profile, 2015 University of Colorado, Boulder
Photometric Trends In The Visible Solar Continuum And Their Sensitivity To The Center-To-Limb Profile, C. L. Peck, M.P. Rast
Astrophysical & Planetary Sciences Faculty Contributions
Solar irradiance variations over solar rotational timescales are largely determined by the passage of magnetic structures across the visible solar disk. Variations on solar cycle timescales are thought to be similarly due to changes in surface magnetism with activity. Understanding the contribution of magnetic structures to total solar irradiance and solar spectral irradiance requires assessing their contributions as a function of disk position. Since only relative photometry is possible from the ground, the contrasts of image pixels are measured with respect to a center-to-limb intensity profile. Using nine years of full-disk red and blue continuum images from the Precision Solar ...
Resolving Emission Lines Of Sodiumlike Fe Xvi Using Ebit, 2015 California Polytechnic State University, San Luis Obispo
Resolving Emission Lines Of Sodiumlike Fe Xvi Using Ebit, Sandi Lavito
STAR (STEM Teacher and Researcher) Program Posters
High resolution crystal spectrometers on sounding rockets and orbiting satellites, such as the Solar Maximum Mission, show strong X-ray emission from the n= 3 to 2 transitions in neon-like Fe XVII. Two of the strongest lines are the 3d to 2p resonance and inter combination lines at 15.01 Å (3C) and 15.26 Å (3D).
Intensity ratios of these solar lines range from ~ 1.6 to 2.8. The lower ratios are a result of a line from Na-like Fe XVI inner shell satellite line blending with the Fe XVII inter combination line, 3D. The wavelength of the Na-like ...
Insights Into Planetesimal Evolution: Petrological Investigations Of Regolithic Howardites And Carbonaceous Chondrite Impact Melts, 2015 University of Tennessee - Knoxville
Insights Into Planetesimal Evolution: Petrological Investigations Of Regolithic Howardites And Carbonaceous Chondrite Impact Melts, Nicole Gabriel Lunning
Asteroidal meteorites are the only available geologic samples from the early part of our solar system’s history. These meteorites contain evidence regarding how the earliest protoplanetary bodies formed and evolved. I use petrological and geochemical techniques to investigate the evolution of these early planetesimals, focusing on two meteorite types: Howardites, which are brecciated samples of a differentiated parent body (thought to be the asteroid 4 Vesta), and CV chondrites, which are primitive chondrites that have not undergone differentiation on their parent body.
Quantitative petrological analysis and characterization of paired regolithic (solar wind-rich) howardites indicate that this large sample of ...
Near-Infrared (2 – 4 Micron) Spectroscopy Of Near-Earth Asteroids: A Search For Oh/H2o On Small Planetary Bodies, 2015 University of Tennessee - Knoxville
Near-Infrared (2 – 4 Micron) Spectroscopy Of Near-Earth Asteroids: A Search For Oh/H2o On Small Planetary Bodies, Nathanael Richard Wigton
Near-Earth asteroids (NEAs) are not expected to have H2O [water] ice on their surfaces because a) most accreted dry and therefore never contained H2O, and b) their relatively high surface temperatures should drive rapid H2O ice sublimation. However, OH/H2O has been detected on other anhydrous inner solar system objects, including the Moon and Vesta. Possible sources for OH/H2O in the inner Solar System might include production via solar wind interactions, carbonaceous chondrite or cometary impact delivery, or native OH/H2O molecules bound to phyllosilicates. As these ...
Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, 2015 Iowa State University
Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa
2016 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.
Optimization Of A Solar Simulator For Planetary-Photochemical Studies, 2015 Paul Scherrer Institute (PSI)
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 ...
Observations Of Solar Cyclical Variations In Geocoronal Hα Column Emission Intensities, 2015 University of Wisconsin-Madison
Observations Of Solar Cyclical Variations In Geocoronal Hα Column Emission Intensities, S. Nossal, F. Roesler, Edwin Mierkiewicz, R. Reynolds
Edwin J. Mierkiewicz
Observations of thermospheric + exospheric Hα column emissions by the Wisconsin Hα Mapper (WHAM) Fabry-Perot (Kitt Peak, Arizona) over the 1997–2001 rise in solar cycle 23 show a statistically significant solar cyclical variation. The higher signal-to-noise WHAM observations corroborate suggestions of a solar cycle trend in the Hα emissions seen in Wisconsin observations over solar cycle 22. Here we compare WHAM 1997 and 2000–2001 winter solstice geocoronal Hα observations toward regions of the sky with low galactic emission. The observed variation in geocoronal hydrogen column emission intensities over the solar cycle is small compared with variations in hydrogen exobase ...
Radial Velocity Observations Of The Extended Lunar Sodium Tail, 2015 Embry-Riddle Aeronautical University - Daytona Beach
Radial Velocity Observations Of The Extended Lunar Sodium Tail, Edwin Mierkiewicz, M. Line, F. Roesler, R. Oliversen
Edwin J. Mierkiewicz
We report the first velocity resolved sodium 5889.950 Å line profile observations of the lunar sodium tail observed in the anti-lunar direction near new Moon. These observations were made on 29 March 2006, 27 April 2006 and 28 April 2006 from Pine Bluff (WI) observatory with a double etalon Fabry-Perot spectrometer at a resolving power of ∼80,000. The observations were made within 2–14 hours from new Moon, pointing near the anti-lunar point. The average observed radial velocity of the lunar sodium tail in the vicinity of the anti-lunar point for the three nights reported was 12.4 ...
Detection Of Diffuse Interstellar [O Ii] Emission From The Milky Way Using Spatial Heterodyne Spectroscopy, 2015 Embry-Riddle Aeronautical University - Daytona Beach
Detection Of Diffuse Interstellar [O Ii] Emission From The Milky Way Using Spatial Heterodyne Spectroscopy, Edwin Mierkiewicz, R. Reynolds, F. Roesler, J. Harlander, K. Jaehnig
Edwin J. Mierkiewicz
Using a newly developed spatial heterodyne spectrometer (SHS), we have obtained the first radial velocity resolved emission-line profiles of diffuse [O II] 3726 and 3729 angstrom emission lines from the warm (10,000 K) ionized component of our Galaxy's interstellar medium. These [O II] lines are a principal coolant for this widespread, photoionized gas and are a potential tracer of variations in the gas temperature resulting from unidentified heating processes that appear to be acting within the Galaxy's disk and halo. By spectrally isolating for the first time Galactic [O II] from atmospheric [O II] emission, we were ...
Production, Outflow, Velocity, And Radial Distribution Of H2o And Oh In The Coma Of Comet C/1995 O1 (Hale-Bopp) From Wide-Field Imaging Of Oh, 2015 University of Wisconsin-Madison
Production, Outflow, Velocity, And Radial Distribution Of H2o And Oh In The Coma Of Comet C/1995 O1 (Hale-Bopp) From Wide-Field Imaging Of Oh, Walter Harris, Frank Scherb, Edwin Mierkiewicz, Ronald Oliversen, Jeffrey Morgenthaler
Edwin J. Mierkiewicz
Observations of OH are a useful proxy of the water production rate (Q H2O) and outflow velocity (VH2O) in comets. From wide-field images taken on 1997 March 28 and April 8 that capture the entire scale length of the OH coma of comet C/1995 O1 (Hale-Bopp), we obtain Q OH from the model-independent method of aperture summation and Q H2O from the OH photochemical branching ratio, BROH. Using an adaptive ring summation algorithm, we extract the radial brightness distribution of OH 0-0 band emission out to cometocentric distances of up to 10 to the sixth power km, both as ...