Physical Sciences and Mathematics Commons^™

Physical Properties Of Brackett Emitters In The Apogee Dr17 Catalog, Elliott Khilfeh, Hunter Campbell, Kevin R. Covey, Marina Kounkel, Richard Ballentyne

WWU Honors College Senior Projects

In the process of accumulating mass (accretion), young stars channel ionized gas from the protoplanetary disk to the stellar surface along magnetic field lines. Upon impacting the photosphere, the gas cools down, recombining and emitting hydrogen spectral lines. Measuring these emission lines allows us to determine the temperature and density of the gas in those accretion streams. This then enables us to test whether those parameters depend on the accretion rate. We present measurements of equivalent widths and line ratios for Brackett (Br) 11 – 20 lines for 3366 observations of 940 pre-main sequence stars observed with APOGEE as of …

Possible Studies On Generalized Parton Distributions And Gravitational Form Factors In Neutrino Reactions, Shunzo Kumano, Roberto Petti

Faculty Publications

Spacelike and timelike generalized parton distributions (GPDs) have been investigated in charged-lepton scattering and electron-positron collisions via deeply virtual Compton scattering and two-photon processes, respectively. Furthermore, we expect that hadron-accelerator-facility measurements will be performed in future. The GPDs will play a crucial role in clarifying the origins of hadron spins and masses in terms of quarks and gluons. It is also possible to probe internal pressure within hadrons for understanding their stability. Gravitational form factors of hadrons used to be considered as a purely academic subject because gravitational interactions are too weak to be measured in microscopic systems. However, due …

Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon …

Hadron-Quark Phase Transition At Finite Density In The Presence Of A Magnetic Field: Anisotropic Approach, Efrain J. Ferrer, Aric Hackebill

Physics and Astronomy Faculty Publications and Presentations

We investigate the hadron-quark phase transition at finite density in the presence of a magnetic field taking into account the anisotropy created by a uniform magnetic field in the system’s equations of state. We find a new anisotropic equilibrium condition that will drive the first-order phase transition along the boundary between the two phases. Fixing the magnetic field in the hadronic phase, the phase transition is realized by increasing the baryonic chemical potential at zero-temperature. It is shown that the magnetic field is mildly boosted after the system transitions from the hadronic to the quark phase. The magnetic-field discontinuity between …

Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson

Information Systems and Engineering Management Research Publications

We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate γ Doradus (γ Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new γ Dor variables. All exhibit sinusoidal variability with amplitudes between 6 and 65 mmag in Johnson B and periods from 0.28 to 1.13 days. All lie in the same region of the H-R diagram as our previously confirmed γ Dor stars. Of the nine systems, one is a single-lined spectroscopic binary (SB1), two are double-lined spectroscopic binaries (SB2), and …

The Expres Stellar Signals Project Ii. State Of The Field In Disentangling Photospheric Velocities, Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. De Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo Iii, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak

Information Systems and Engineering Management Research Publications

Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme-precision radial-velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The Extreme-precision Spectrograph (EXPRES) Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed radial-velocity (RV) correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when …

Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon …

Computational Data Of Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain, N. Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti

Physics and Astronomy Faculty Publications and Presentations

The data presented in this paper refer to the research article "Dry and Hydrated Defective Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain for Hydrogen Evolution from Water Splitting: A First-principle Study". Here, we present the Density Functional Theory (DFT) data used to generate optimal geometries and electronic structure for the MoS2/graphene heterostructure under strain, for dry and hydrated pristine and defect configurations. We also report DFT data used to obtain hydrogen Gibbs free energies for adsorption on the MoS2 monolayer and on graphene of the heterostructure. The DFT data were calculated using the periodic DFT code CRYSTAL17, which employs Gaussian basis …

Spin-Orbit Gravitational Locking - An Effective Potential Approach, Christopher Clouse, Andrea Ferroglia, Miguel C. N. Fiolhais

Publications and Research

The objective of this paper is to study the tidally locked 3:2 spin–orbit resonance of Mercury around the Sun. In order to achieve this goal, the effective potential energy that determines the spinning motion of an ellipsoidal planet around its axis is considered. By studying the rotational potential energy of an ellipsoidal planet orbiting a spherical star on an elliptic orbit with fixed eccentricity and semi-major axis, it is shown that the system presents an infinite number of metastable equilibrium configurations. These states correspond to local minima of the rotational potential energy averaged over an orbit, where the ratio between …

Oxygen Ion Escape At Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability, Tong Dang, Xuanye Ma, Jiuhou Le, Binzheng Zhang, Tielong Zhang, Zhonghua Yao, John Lyon, Sudong Xiao, Maodong Yan, Oliver Brambles, Kareem Sorathia

Publications

How oxygens escape from Venus has long been a fundamental but controversial topic in the planetary research. Among various key mechanisms, the Kelvin-Helmholtz instability (KHI) has been suggested to play an important role in the oxygen ion escape from Venus. Limited by either scarce in-situ observations or simplified theoretical estimations, the mystery of oxygen ion escape process associated with KHI is still unsettled. Here we present the first three-dimensional configuration of KHI at Venus with a global multifluid magnetohydrodynamics model, showing a significantly fine structure and evolution of the KHI. KHI mainly occurred at the low latitude boundary layer if …

Neutron Stars With Baryon Number Violation, Probing Dark Sectors, Jeffrey M. Berryman, Susan Gardner, Mohammadreza Zakeri

Physics and Astronomy Faculty Publications

The neutron lifetime anomaly has been used to motivate the introduction of new physics with hidden-sector particles coupled to baryon number, and on which neutron stars provide powerful constraints. Although the neutron lifetime anomaly may eventually prove to be of mundane origin, we use it as motivation for a broader review of the ways that baryon number violation, be it real or apparent, and dark sectors can intertwine and how neutron star observables, both present and future, can constrain them.

The Arecibo Observatory As An Instrument For Investigating Orbital Debris: Legacy And Next Generation Performance, James Murray, Fredrick A. Jenet

Physics and Astronomy Faculty Publications and Presentations

In this paper, we investigate the ability of the Arecibo Observatory to characterize the orbital debris environment and compare it to the primary instrument used by NASA's Orbital Debris Program Office, the Haystack Ultra-Wideband Satellite Imaging Radar (HUSIR). Arecibo's location (183 N) increases the percentage of observable orbits (relative to HUSIR) by 27%, which gives Arecibo access to a much larger and previously unmeasured portion of the environment. Due to the recent collapse of the Arecibo dish, in addition to exploring historic capabilities of the Legacy Arecibo Telescope, estimates of the performance of the proposed Next Generation Arecibo Telescope (NGAT) …

A Multiparameter Degeneracy In Microlensing Events With Extreme Finite Source Effects, Samson A. Johnson, Matthew T. Penny, B. Scott Gaudi

Faculty Publications

For microlenses with sufficiently low mass, the angular radius of the source star can be much larger than the angular Einstein ring radius of the lens. For such extreme finite source effect (EFSE) events, finite source effects dominate throughout the duration of the event. Here, we demonstrate and explore a continuous degeneracy between multiple parameters of such EFSE events. The first component in the degeneracy arises from the fact that the directly observable peak change of the flux depends on both the ratio of the angular source radius to the angular Einstein ring radius and the fraction of the baseline …

Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vii. Xmm-Newton Observations Of Lensed Quasars, Thomas Connor, Daniel Stern, Alberto Krone-Martins, S. G. Djorgovski, Matthew J. Graham

Faculty Publications

We present XMM-Newton X-ray observations of nine confirmed lensed quasars at 1 less than or similar to z less than or similar to 3 identified by the Gaia Gravitational Lens program. Eight systems are strongly detected, with 0.3-8.0 keV fluxes F (0.3-8.0) greater than or similar to 5 x10(-14) erg cm(-2) s(-1). Modeling the X-ray spectra with an absorbed power law, we derive power-law photon indices and 2-10 keV luminosities for the eight detected quasars. In addition to presenting sample properties for larger quasar population studies and for use in planning for future caustic-crossing events, we also identify three quasars …

Ultra-Broadband Bending Beam And Bottle Beam Based On Acoustic Metamaterials, Xudong Fan, Xiaolong Huang, Yang Kang, Can Li, Ning Li, Chunsheng Weng, Likun Zhang

Faculty and Student Publications

We report the realization of an ultra-broadband bending beam based on acoustic meta-materials by the theoretical prediction and the numerical validation. The proposed structure is composed of a series of straight tubes with spatially modulated depths. We analytically derive the depth profile required for the generation of an ultra-broadband bending beam, and examine the performance of the metastructure numerically. The design is then extended for the generation of a three-dimensional bottle beam. The transverse trapping behaviours on small rigid objects by the bottle beam are investigated based on the force potential. Our work will help the further study of broadband …

Search For B0 Meson Decays Into Λ And Missing Energy With A Hadronic Tagging Method At Belle, C. Hadjivasiliou, B. G. Fulsom, J. F. Strube, I. Adachi, H. Aihara, D. M. Asner, H. Atmacan, T. Aushev, V. Babu, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, D. Bodrov, J. Borah, A. Bozek

Faculty and Student Publications

We present a search for the decays of B0 mesons into a final state containing a Λ baryon and missing energy. These results are obtained from a 711 fb-1 data sample that contains 772×106 BB¯ pairs and was collected near the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode and require the remainder of the event to consist of only a single Λ. No evidence for these decays is found, and we set 90% confidence level upper limits on the …

A Pair Of Sub-Neptunes Transiting The Bright K-Dwarf Toi-1064 Characterized With Cheops, T. G. Wilson, E. Goffo, Y. Alibert, D. Gandolfi, A. Bonfanti, C. M. Persson, A. Collier Cameron, M. Fridlund, L. Fossati, J. Korth, W. Benz, A. Deline, H.-G. Florén, P. Guterman, V. Adibekyan, M. J. Hooton, S. Hoyer, A. Leleu, A. J. Mustill, S. Salmon, S. G. Sousa, O. Suarez, L. Abe, A. Agabi, R. Alonso, G. Anglada, J. Asquier, T. Bárczy, D. Barrado Navascues, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, N. Billot, X. Bonfils, A. Brandeker, C. Broeg, E. M. Bryant, M. R. Burleigh, M. Buttu, J. Cabrera, S. Charnoz, D. R. Ciardi, R. Cloutier, W. D. Cochran, K. A. Collins, K. D. Colón, N. Crouzet, S. Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. Demangeon, B.-O. Demory, D. Dragomir, G. Dransfield, D. Ehrenreich, A. Erikson, A. Fortier, T. Gan, S. Gill, M. Gillon, C. L. Gnilka, N. Grieves, S. Grziwa, M. Güdel, T. Guillot, J. Haldemann, K. Heng, K. Horne, S. B. Howell, K. G. Isaak, J. M. Jenkins, Eric L.N. Jensen, L. Kiss, G. Lacedelli, K. Lam, J. Laskar, D. W. Latham, A. Lecavelier Des Etangs, M. Lendl, K. V. Lester, A. M. Levine, J. Livingston, C. Lovis, R. Luque, D. Magrin, W. Marie-Sainte, P. F. L. Maxted, A. W. Mayo, B. Mclean, M. Mecina, D. Mékarnia, V. Nascimbeni, L. D. Nielsen, G. Olofsson, H. P. Osborn, H. L. M. Osborne, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, S. Redfield, I. Ribas, G. R. Ricker, M. Rieder, N. C. Santos, G. Scandariato, F.-X. Schmider, R. P. Schwarz, N. J. Scott, S. Seager, D. Ségransan, L. M. Serrano, A. E. Simon, A. M. S. Smith, M. Steller, C. Stockdale, G. Szabó, N. Thomas, E. B. Ting, A. H. M. J. Triaud, S. Udry, V. Van Eylen, V. Van Grootel, R. K. Vanderspek, V. Viotto, N. Walton, J. N. Winn

Physics & Astronomy Faculty Works

We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine T_eff,* = 4734 ± 67 K, R_* = 0.726 ± 0.007 R_⊙, and M_* = 0.748 ± 0.032 M_⊙. We present a …

Transit Timings Variations In The Three-Planet System: Toi-270, L. Kaye, S. Vissapragada, M. N. Günther, S. Aigrain, T. Mikal-Evans, Eric L.N. Jensen, H. Parviainen, F. J. Pozuelos, L. Abe, J. S. Acton, A. Agabi, D. R. Alves, D. R. Anderson, D. J. Armstrong, K. Barkaoui, O. Barragán, B. Benneke, P. T. Boyd, R. Brahm, I. Bruni, E. M. Bryant, M. R. Burleigh, S. L. Casewell, D. Ciardi, R. Cloutier, K. A. Collins, K. I. Collins, D. M. Conti, I. J. M. Crossfield, N. Crouzet, T. Daylan, D. Dragomir, G. Dransfield, D. Fabrycky, M. Fausnaugh, G. Fuűrész, T. Gan, S. Gill, M. Gillon, M. R. Goad, V. Gorjian, M. Greklek-Mckeon, N. Guerrero, T. Guillot, E. Jehin, J. S. Jenkins, M. Lendl, J. Kamler, S. R. Kane, J. F. Kielkopf, M. Kunimoto, W. Marie-Sainte, J. Mccormac, D. Mékarnia, F. Y. Morales, M. Moyano, E. Palle, V. Parmentier, H. M. Relles, F.-X. Schmider, R. P. Schwarz, S. Seager, A. M. S. Smith, T.-G. Tan, J. Taylor, A. H. M. J. Triaud, J. D. Twicken, S. Udry, J. I. Vines, G. Wang, P. J. Wheatley, J. N. Winn

Physics & Astronomy Faculty Works

We present ground- and space-based photometric observations of TOI-270 (L231-32), a system of three transiting planets consisting of one super-Earth and two sub-Neptunes discovered by TESS around a bright (K-mag = 8.25) M3V dwarf. The planets orbit near low-order mean-motion resonances (5:3 and 2:1) and are thus expected to exhibit large transit timing variations (TTVs). Following an extensive observing campaign using eight different observatories between 2018 and 2020, we now report a clear detection of TTVs for planets c and d, with amplitudes of ~10 min and a super-period of ~3 yr, as well as significantly refined estimates of the …

Search For Intermediate-Mass Black Hole Binaries In The Third Observing Run Of Advanced Ligo And Advanced Virgo, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

Intermediate-mass black holes (IMBHs) span the approximate mass range 100−10⁵ M_⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M_⊙ providing direct evidence of …

Development And Validation Of An Astronomy Self-Efficacy Instrument For Understanding And Doing, Rachel Freed, David Mckinnon, Michael Fitzgerald, Christina M. Norris

Research outputs 2022 to 2026

This paper presents a new astronomy self-efficacy instrument, composed of two factors; one relating to learning astronomy content, which we call astronomy personal self-efficacy, and the other relating to the use of astronomical instrumentation, specifically the use of remote robotic telescopes for data collection. The latter is referred to as the astronomy instrumental self-efficacy factor. The instrument has been tested for reliability and construct validity. Reliability testing showed that factor 1 had a Cronbach's α of 0.901 and factor 2 had a Cronbach's α of 0.937. Construct validity was established by computing one-way analyses of variances, with the p value …

Search For A Light Higgs Boson In Single-Photon Decays Of ϒ (1s) Using ϒ (2s) →Π+Π- ϒ (1s) Tagging Method, S. Jia, C. P. Shen, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, A. Bobrov, D. Bodrov

Faculty and Student Publications

We search for a light Higgs boson (A0) decaying into a τ+τ- or μ+μ- pair in the radiative decays of ϒ(1S). The production of ϒ(1S) mesons is tagged by ϒ(2S)→π+π-ϒ(1S) transitions, using 158×106 ϒ(2S) events accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant A0 signals in the mass range from the τ+τ- or μ+μ- threshold to 9.2 GeV/c2 are observed. We set the upper limits at 90% credibility level (C.L.) on the product branching fractions for ϒ(1S)→γA0 and A0→τ+τ- varying from 3.8×10-6 to 1.5×10-4. Our results represent an approximately twofold improvement on the current …

A Skateboarding Experiential Learning Activity For Introductory Physics, Liang Zeng, Guang Zeng, Oscar Guerrero, George Garcia

Physics and Astronomy Faculty Publications and Presentations

Instructors of introductory college physics courses are in a unique position to explain the physics of skateboarding and its associated risks. A field trip to a skate park to explore the law of conservation of energy and measure the impact forces can enhance student analytical thinking skills and their appreciation of physics in everyday life. Through the measurement of the impact forces and student discussions of their own skateboarding experiences, students are better prepared to protect themselves from skateboarding-related physical injuries. Due to its flexible and creative nature, skateboarding has become a popular action sport worldwide. In the United States, …

Erratum: Chandra Grating Spectroscopy Of Embedded Wind Shock X-Ray Emission From O Stars Shows Low Plasma Temperatures And Significant Wind Absorption, David H. Cohen, Winter Parts, Graham M. Doskoch, Jiaming Wang, Veronique Petit, Maurice A. Leutenegger, Marc Gagné

Earth & Space Sciences Faculty Publications

This is an erratum to the paper ‘ Chandra grating spectroscopy of embedded wind shock X-ray emission from O stars shows low plasma temperatures and significant wind absorption’ (2021, MNRAS, 503, 715). We present here a modest correction to the o v erall scaling of the differential emission measures (DEMs) of six O stars originally presented in Cohen et al. ( 2021 ). While working on a follow-up paper, we realized that we had incorrectly converted the bvapec spectral emission model’s normalization parameters (proportional to the emission measure per temperature bin size) to the emission measure per decade Kelvin shown …

Measurement Of The Nucleon F N2 / F P2 Tructure Function Ratio By The Jefferson Lab Marathon Tritium/Helium-3 Deep Inelastic Scattering Experiment, D. Abrams, H. Albataineh, B. S. Aljawrneh, S. Alsalmi, D. Androic, K. Aniol, W. Armstrong, J. Arrington, H. Atac, T. Averett, C. Ayerbe Gayoso, X. Bai, J. Bane, S. Barcus, A. Beck, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, D. Blyth, Roberto Petti, Et. Al.

Faculty Publications

The ratio of the nucleon F₂ structure functions, F ⁿ₂ / F ^p₂ is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ³H and ³He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken …

Search Full Text Options Here 2 Of 4 Kmt-2021-Blg-0912lb: A Microlensing Super Earth Around A K-Type Star, Cheongho Han, Ian A. Bond, Jennifer C. Yee, Weicheng Zang, Michael D. Albrow

Faculty Publications

Aims. The light curve of the microlensing event KMT-2021-BLG-0912 exhibits a very short anomaly relative to a single-lens single-source form. We investigate the light curve for the purpose of identifying the origin of the anomaly.

Methods. We model the light curve under various interpretations. From this, we find four solutions, in which three solutions are found under the assumption that the lens is composed of two masses (2L1S models), and the other solution is found under the assumption that the source is comprised of binary stars (1L2S model). The 1L2S model is ruled out based on the contradiction that the …

The World As We Know It: Maps And Atlases From Special Collections, Archives And Special Collections, Luke Meagher

Library Exhibits

Selections of maps and atlases from Sandor Teszler Library’s Special Collections are presented in this exhibit to show how, over time, cartographers have represented the world as we know it.

The Extent, Nature, And Origin Of K And Rb Depletions And Isotopic Fractionations In Earth, The Moon, And Other Planetary Bodies, Nicolas Dauphas, Nicole X. Nie, Marc Blanchard, Zhe J. Zhang, Hao Zeng, Justin Y. Hu, Merlin Meheut, Channon Visscher, Robin Canup, Timo Hopp

Faculty Work Comprehensive List

Moderately volatile elements (MVEs) are depleted and isotopically fractionated in the Moon relative to Earth. To understand how the composition of the Moon was established, we calculate the equilibrium and kinetic isotopic fractionation factors associated with evaporation and condensation processes. We also reassess the levels of depletions of K and Rb in planetary bodies. Highly incompatible element ratios are often assumed to be minimally affected by magmatic processes, but we show that this view is not fully warranted, and we develop approaches to mitigate this issue. The K/U weight ratios of Earth and the Moon are estimated to be 9704 …

Venus Mountain Waves In The Upper Atmosphere Simulated By A Time-Invariant Linear Full-Wave Spectral Model, Michael P. Hickey, Richard L. Walterscheid, Thomas Navarro, Gerald Schubert

Publications

A 2-D spectral full-wave model is described that simulates the generation and propagation of mountain waves over idealized topography in Venus' atmosphere. Modeled temperature perturbations are compared with the Akatsuki observations. Lower atmosphere eddy diffusivity and stability play a major role in the upward propagation of gravity waves from their mountain sources. Two local times (LT) are considered. For LT = 11 h the waves are blocked by a critical level near 100 km altitude, while for LT = 16 h the waves propagate into the thermosphere. As a result of the small scale height in the Venus thermosphere, for …

Determining If Active Galactic Nuclei (Agn) Jets Can Survive The Cold Fronts Of Merger Galaxies, Stephen Walker, Isabelle Wingate

Summer Community of Scholars (RCEU and HCR) Project Proposals

No abstract provided.

Chandra Revisits Wr 48a: Testing Colliding Wind Models In Massive Binaries, Svetozar A. Zhekov, Marc Gagné, Stephen L. Skinner

Earth & Space Sciences Faculty Publications

We present results of new Chandra High-Energy Transmission Grating (HETG) observations (2019 November-December) of the massive Wolf-Rayet binary WR 48a. Analysis of these high-quality data showed that the spectral lines in this massive binary are broadened (full width at half-maximum, FWHM = 1400 km s(-1)) and marginally blueshifted (similar to-100 km s(-1)). A direct modelling of these high-resolution spectra in the framework of the standard colliding stellar wind (CSW) picture provided a very good correspondence between the shape of the theoretical and observed spectra. Also, the theoretical line profiles are in most cases an acceptable representation of the observed ones. …