Bulletin of the American Physical Society
2018 Joint Fall Meeting of the Texas Sections of APS, AAPT and Zone 13 of the SPS
Volume 63, Number 18
Friday–Saturday, October 19–20, 2018; University of Houston, Houston, Texas
Session K05: Astronomy and Astrophysics II |
Hide Abstracts |
Chair: Samina Masood, University of Houston, Clearlake Room: Science and Engineering Classroom (SEC) 204 |
Saturday, October 20, 2018 10:00AM - 10:12AM |
K05.00001: The Cooling of the Crab Pulsar Brianna T Douglas, William G Newton, Lauren E Balliet Neutron stars are one of the most exotic objects in the universe. They are complex due to their extremely high densities. Trying to find the equation of state (EOS) exceeding nuclear saturation density is a high priority for nuclear astrophysics. One way to constrain the EOS is to learn more about the cooling processes of neutron stars over time. Stars cool from one of two ways: emission of thermal radiation from the surface or through the emission of neutrinos from the interior of the star. There’s some circumstantial evidence that the Crab pulsar was formed in an electron-capture supernova, which is one way stars about 8-10 solar masses die. In this type of supernova, the star’s core collapses at the ONeMg stage, and produces a relatively low mass neutron star of around 1.25 Msun. It is not certain the Crab formed this way, but in this talk we explore the possibility of ruling out the electron capture supernova scenario, and of placing constraints on the neutron star EOS, by calculating the cooling of low mass neutron stars and comparing with the measured upper limit on the Crab’s temperature. We do this using an ensemble of nuclear EOSs spanning the current uncertainty in the nuclear symmetry energy and the maximum mass and moment of inertia of neutron stars. |
Saturday, October 20, 2018 10:12AM - 10:24AM |
K05.00002: Understanding Stellar Evolution Through Numerical Simulations of Binary Star Systems Mitchell T Ford, Blagoy Rangelov Most stars form in binary or multiple systems. At least half of all solar-like stars have companions and that fraction approaches 100% for massive stars. A large fraction of these systems will interact in some way and change the evolution of the companions, leading to the production of exotic objects beyond standard stellar evolution models. Binary star evolution can lead to the formation of exotic objects such as supernovae, gamma-ray bursts, and sources of gravitational wave progenitors. We used the binary_c code for binary stellar evolution to simulate stars ranging from 0.5 to 100 Msun and investigate the endpoints of stellar evolution. We focus on understanding the final stages of the evolution of massive stars. |
Saturday, October 20, 2018 10:24AM - 10:36AM |
K05.00003: Quantum Magnetic Collapse in Binary Systems Craig L Brooks Quantum magnetic collapse is a possible phenomena that may occur in degenerate stars. If the pressure that is transverse to the magnetic field generated by the neutron star vanishes, it may lead to a collapse of the system. Such a collapse may result in a stellar remnant (such as a neutron star) that is elongated in the direction of the magnetic field or, for particular wavelengths, photons may be captured by strongly magnetized neutron stars. In particular, we desire to build upon the work of Chaichian et, al (2000) by considering magnetic collapse in binary systems. The standard electroweak theory establishes that the upper limit of the magnetic field is Mw2/e = 1024 G, which arises from the ground state of W± bosons. While the strength of the magnetic field may inhibit accretion efficiency, if the matter flux is sufficiently low, we can expect the accretion rate to not exceed Eddington efficiency. We then seek to determine how much the accreted matter contributes to the bosonic and leptonic chemical potential. |
Saturday, October 20, 2018 10:36AM - 10:48AM |
K05.00004: Narrowing down neutron stars' crustal properties using cooling data Michael Ross, William G Newton LMXBs KS 1730-260 and MXB 1659-29 are two neutron stars among many that have been observed to accrete matter from a companion star and cool after quiescence begins. Cooling data for KS 1730-260 and MXB 1659-29 have been provided by the Chandra and XMM-Newton telescopes. Using Dr. Ed Brown’s dStar we ran models for stars with solar masses of 1.2 Msun to 1.8 Msun to check if a relationship between the inferred crustal impurity of these stars and the slope of their symmetry energies existed. The most accurate models for each mass group (1.2, 1.4, 1.6, and 1.8 Msun) had symmetry energies with slopes of L=20. The higher mass stars (1.6, 1.8 Msun) also had slopes of L=40 in their most accurate results. The value of the impurity parameter for each mass group increased as M increased: for M=1.2 Msun, Qimp varied between 0.01-0.092. For M=1.8 Msun, Qimp varied between 0.38-3.38. |
Saturday, October 20, 2018 10:48AM - 11:00AM |
K05.00005: Depth of a Neutron Star Crust Lauren E Balliet, William G Newton, Brianna T Douglas Neutron stars are a valuable asset to modern nuclear astrophysics in that they provide a unique environment to study matter under extreme conditions. Much of the observational data obtained from neutron stars contains information about the structure and dynamics of the crust. Using such observations to measure crust properties requires understanding the uncertainty range from models of the thickness of the different layers of the crust. These uncertainties arise from uncertainties in the properties of nuclear matter. In this talk, I will use a comprehensive ensemble of nuclear matter equations of state, spanning the current uncertainty in the nuclear interaction, to examine the correlations between the crust thickness and nuclear matter parameters. I will compare the results of a number of different ways to calculate the crust thickness, and use them to estimate the uncertainty in estimates of crust oscillation frequencies and the crust cooling time. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700