Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session B14: Planetary Science |
Hide Abstracts |
Sponsoring Units: DAP Chair: Dan McCammon, University of Wisconsin-Madison Room: Plaza Court 4 |
Saturday, May 2, 2009 10:45AM - 10:57AM |
B14.00001: Demixing of Hydrogen and Helium at High Pressures Winfried Lorenzen, Bastian Holst, Nadine Nettelmann, Ronald Redmer We have performed quantum molecular dynamics simulations based on finite-temperature density functional theory for warm dense hydrogen-helium mixtures for conditions relevant for the interior of giant planets. We derive the miscibility gap from the EOS data and discuss the consequences for the interior structure of Jupiter and Saturn. Calculations of the electrical conductivity show that demixing is mainly caused by metallization in the hydrogen component. The results can be used to explain or motivate layer structures inside planets and have a strong impact on the luminosity and age of Saturn which has long been assumed. [Preview Abstract] |
Saturday, May 2, 2009 10:57AM - 11:09AM |
B14.00002: Ab initio equation of state data and interior structure of giant planets Ronald Redmer, Nadine Nettelmann, Ulrike Kramm, Winfried Lorenzen, Bastian Holst, Martin French We have performed quantum molecular dynamics simulations using finite-temperature density functional theory (FT-DFT-MD) to calculate accurate equation of state data for the most abundant materials in giant planets hydrogen, helium, and water in the warm dense matter region. We discuss the phase diagram of water up to ultra-high pressures and identify the location of the superionic phase which might occur in the deep interior of Neptune, Uranus or even in Saturn. These ab initio data sets were used to calculate the interior structure models of solar giant planets within the standard three-layer model and to determine their core mass and metallicity. We have also determined possible compositions of extrasolar giant planets such as GJ 436b for which the mass-radius relation and the surface temperature are measured. We discuss also the impact of high-pressure effects such as the nonmetal-to-metal transition in hydrogen and the demixing of hydrogen and helium on the interior structure of giant planets. [Preview Abstract] |
Saturday, May 2, 2009 11:09AM - 11:21AM |
B14.00003: Is a Fundamental ``Constant'' Changing in Space/Time? Louise Riofrio Exploration of the Moon and Mars may yield benefits for physics. Geology and paleontology show that early Earth and Mars had conditions for liquid water and possibly life nearly 3.5 Gyr ago. According to standard models, solar luminosity was only 75{\%} of today's value. Earth and Mars would have been frozen solid. Models must infer an extremely high concentration of gases such as CH4 or CO2 simultaneously heating both planets. Research on variability of fundamental constants is highly recommended in the Science Vision Document,~ in the ESA-ESO Working Group (WG) report on Fundamental Cosmology and is one of the~ science cases considered by the ESO WG on ELT. Since the sun turns fuel to energy according to $E=mc^2$ an expanding cosmology where c is related to time would provide nearly constant solar luminosity. The Lunar Laser Ranging Experiment from 1969 measures the Moon's recession at precisely 3.82 cm/yr, anomalously high. Geological evidence states that average recession is only 2.9 $\pm $ 0.6 cm/yr. If c slows according to $GM=tc^3$, that would precisely account for the discrepancy. The ``most profound mystery'' of Type Ia supernovae may also be explained. Supernova redhsifts appear to accelerate, leading to speculation about dark energies. A theory's prediction provides a precise fit to observations. Corroborating data from the Moon and Mars may indicate a ``c change'' in physics. [Preview Abstract] |
Saturday, May 2, 2009 11:21AM - 11:33AM |
B14.00004: ABSTRACT WITHDRAWN |
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