Bulletin of the American Physical Society
Joint Meeting of the Four Corners and Texas Sections of the American Physical Society
Volume 61, Number 15
Friday–Saturday, October 21–22, 2016; Las Cruces, New Mexico
Session H1: Astronomy and Astrophysics |
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Chair: Steve Stochaj, New Mexico State University Room: Exhibit Hall 2 |
Saturday, October 22, 2016 9:36AM - 10:00AM |
H1.00001: Brown Dwarf Binary Systems, The Coolest Pairs Around Invited Speaker: Denise Stephens Brown Dwarfs are small substellar objects that are probably more of a dark red or magenta hue than brown. They span the temperature and mass range between the gas giant-planets and the lowest-mass stars, and are important for understanding the physics of both. We believe that brown dwarfs form like stars, but as they cool like a planet, different types of clouds will condense in their atmosphere and the dominant molecules will change. Their very existence provides clues as to how stars form, while their changing atmosphere reveals much about how a hot, young extrasolar planet will cool over billions of years. Of particular interest are the brown dwarf/brown dwarf binary systems. If we can determine the binary fraction of brown dwarfs, we can apply this fraction as a constraint on star formation models. The calculation of the orbital parameters of a brown dwarf binary system provides a direct measurement for the mass of the two objects, which when combined with the their luminosity and temperature, can be used to constrain evolutionary models. This constraint is critical to understanding the atmospheres of directly imaged hot, young extrasolar planets whose temperatures are the same as the brown dwarfs we study. In this talk I will review the characteristics of brown dwarfs, why we are interested in the discovery and characterization of binary systems, and what we are doing with HST data to try and detect and characterize marginally resolved brown dwarf binary systems. [Preview Abstract] |
Saturday, October 22, 2016 10:00AM - 10:12AM |
H1.00002: The slowly varying corona from DEMs with the EVE data set Sam Schonfeld, Stephen White, Rachel Hock-Mysliwiec, James McAteer We present a differential emission measure (DEM) analysis of the slowly varying corona during the first half of solar cycle 24. Using the Extreme ultraviolet Variability Experiment (EVE) and the CHIANTI atomic line database we identify strong isolated iron emission lines present in the non-flaring spectrum with peak emissions covering the coronal temperature range of 5.7 \textless log(T) \textless 6.5. These lines are used to generate daily DEMs from EVE spectra to observe the long term variability of global coronal thermal properties. We discuss the choice of emission lines and the implications of this data set for the relationship between EUV and the F$_{\mathrm{10.7}}$ radio flux. [Preview Abstract] |
Saturday, October 22, 2016 10:12AM - 10:24AM |
H1.00003: Uncatalogued Variable Stars found in two of the Kepler Mission Fields Pamela Lara, Michael Joner The Kepler Mission in its search for planets orbiting a star outside of our solar system --exoplanets-, opened the doors to important findings in Astronomy. The opportunity was given to higher education institution and other groups to confirm the findings proposed by Kepler's. Beside the possibility of concentrating on a given star, now there was a whole field, $+$- 1000 stars, to harvest for knowledge and information. This was the case for the presenter: through a Research Experience for Undergraduates --REU- at Brigham Young University, under the advisory of Dr. Michael Joner, seven new variable stars and star systems were found. Working with the 0.9m optical telescope at West Mountain Observatory, enough data was collected and processed, using Differential Photometry, to obtain Light Curves graphs of the seven object. [Preview Abstract] |
Saturday, October 22, 2016 10:24AM - 10:36AM |
H1.00004: Search For Variable Stars with ROTSE Jasmine Liu, Robert Kehoe, Farley Ferrante Our research group at SMU employs the SMU owned Robotic Optical Transient Search Experiment (ROTSE)-IIIb telescope sited at McDonald Observatory in West Texas to study the most extreme cataclysmic events -- supernovae and gamma-ray bursts. These studies rely on an accurate understanding of the variable star background, which can mimic these stellar death phenomena. Since 2007, the Variable Star Project (VSP) has involved SMU undergraduates in extracting variable star discoveries from the data sample of the ROTSE-I and ROTSE-III telescope. Briefly, we search for potential variable stars and phase light curves of multiple nights together to gain a complete measurement of period and amplitude. When necessary, we augment ROTSE database measurement with additional data from other survey telescopes. The final identification step involves submission of the analysis to the International Variable Star Index (VSX) for referee consideration and potential approval as a variable discovery. VSX is sanctioned by the International Astronomical Union, so resulting discoveries and measurements are publicly available to the astronomical research community. Over the last summer, I successfully submitted three variable stars identified using data from two different telescopes, ROTSE-I and ROTSE-III, for VSX referee approval. These variable stars were all eclipsing binary stars, including one Beta Lyrae (EB) variable and two W Ursae Majoris (EW) variables. An exceptionally rare high amplitude delta scuti triple mode pulastor found by other members of our research group will also be included. [Preview Abstract] |
Saturday, October 22, 2016 10:36AM - 10:48AM |
H1.00005: Exploring Lattice Bolzmann Fluid Methods for Astrophysics Jacob Tinnin, David Neilsen Relativistic fluid dynamics can be computationally challenging for astrophysical systems that have very dynamic, but rarefied gases. Lattice Boltzmann fluid methods have recently been extended to relativistic fluids. These methods are based on a minimal lattice version of the kinetic Boltzmann equation, and they are efficient and easily parallelized. We use this method to model a blast wave interacting with a rarefied gas. We present tests of the method and preliminary results. [Preview Abstract] |
Saturday, October 22, 2016 10:48AM - 11:00AM |
H1.00006: Cosmic and Smaller Scale Astrophysical Plots have Induction and Other Patterns Related to Atomic Scales and Nuclear Properties by Basic Mathematic Rob Allen Cosmic scale induction distributions and super nova patterns can be modeled with some surprisingly simple equations using combinations of basic numbers such as e (the natural logarithm base) and Pi in sequential groups that yield many physical constants. Novel equations produce a large number of parameters ranging from nucleons to macro scale physics, and to astrophysics. Gravity becomes easily related to the other forces. The first expansion of the Big Bang, Inflation, gravity slowing, and Dark Energy accelerations can all come from properties of hexagon ring clusters. Hexagon rings in chemistry explain fractional chemical bonds. Quark fractional charges are likely to come from nuclear scale hexagon properties. Dark Energy and Cold Dark Matter measurements are related to electrically neutralized hexagon rings. Rings reveal some orderly patterns in particle masses. [Preview Abstract] |
Saturday, October 22, 2016 11:00AM - 11:12AM |
H1.00007: Simulating Ejecta from Binary Neutron Star Coalescence using SPH Hyun Lim, Nicolas de Brye, Daniel George, Glen Hordemann, Julien Loiseau, Jonah Miller, Jonathan Sharman Observational signatures of binary neutron star mergers include gravitational waves and faint supernova-like transients that are powered by the radioactive decay of freshly synthesized heavy elements. We use smoothed particle hydrodynamics (SPH), which is well suited for such problems, and adapt the highly scalable 2HOT code to simulate these events. Further, we augment 2HOT by incorporating tabulated equations of state to improve the physical content of the simulations. This additional physics input introduces overhead. To maintain good performance and scalability, we optimize the nearest-neighbor search algorithm intrinsic to the code. In particular, we experiment with different domain partitioning schemes and problem space representations. We comment on how retaining good performance while adding new physics has provided a unique opportunity to practice principles of co-design within a collaboration between physicists and computer scientists. [Preview Abstract] |
Saturday, October 22, 2016 11:12AM - 11:24AM |
H1.00008: Estakhr's Relativistic Decomposition of Four-Velocity Vector Field of Big Bang (Big Bang's Turbulence) Ahmad Reza Estakhr ${\overline{U}^{\mu}=\lim_{\tau\rightarrow\infty}({\frac{1}{\tau}}\int_{o}^{\tau}U^{\mu} d\tau)}$ where the $\tau$ is proper time and $\tau_{o}=0$ is the beginning of the universe. ${U^{\mu}=\overline{U}^{\mu}+U'^{\mu}}$ Estakhr's decomposition is a mathematical technique to separate the average and fluctuating parts of Big Bang. where the $\overline{U}^{\mu}$ denotes the proper time average called steady component of big bang and $U'^{\mu}$ is fluctuating part called Big Bang's perturbations (Big Bang's Turbulence). Estakhr's Proper-Time Averaged of Material-Geodesic Equations Using this mathematical technique, (applications: Big Bang Hydrodynamics, Supernova Hydrodynamics, etc...) ${\frac{D\overline{J}^{\mu}}{D\tau}=\overbrace{\overline{J}^{\nu}\partial_{\nu}\overline{U}^{\mu}+\partial_{\nu}\overline{T}^{\mu\nu}+\Gamma^{\mu}_{\alpha\beta}\overline{J}^{\alpha}\overline{U}^{\beta}}^{\text{Steady Component}}+\overbrace{\partial_{\nu}R^{\mu\nu}+\Gamma^{\mu}_{\alpha\beta}R^{\alpha\beta}}^{Perturbations}}$ EAMG equations are proper time-averaged equations of relativistic motion for fluid flow and used to describe Relativistic Turbulent Flows (such as big bang eruption and/or supernova, etc ...). [Preview Abstract] |
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