2,866 research outputs found

    Note on the Electron Energy Spectrum in the Inner Van Allen Belt

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    Electron energy spectrum in the inner van allen bel

    Relativistic Effects in Extrasolar Planetary Systems

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    This paper considers general relativistic (GR) effects in currently observed extrasolar planetary systems. Although GR corrections are small, they can compete with secular interactions in these systems and thereby play an important role. Specifically, some of the observed multiple planet systems are close to secular resonance, where the dynamics is extremely sensitive to GR corrections, and these systems can be used as laboratories to test general relativity. For the three-planet solar system Upsilon Andromedae, secular interaction theory implies an 80% probability of finding the system with its observed orbital elements if GR is correct, compared with only a 2% probability in the absence of GR. In the future, tighter constraints can be obtained with increased temporal coverage.Comment: Accepted for publication in International Journal of Modern Physics D; this paper received ``Honorable Mention'' in the 2006 Essay Competition of the Gravity Research Foundation; 9 pages including 1 figur

    Planetary image conversion task

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    The Planetary Image Conversion Task group processed 12,500 magnetic tapes containing raw imaging data from JPL planetary missions and produced an image data base in consistent format on 1200 fully packed 6250-bpi tapes. The output tapes will remain at JPL. A copy of the entire tape set was delivered to US Geological Survey, Flagstaff, Ariz. A secondary task converted computer datalogs, which had been stored in project specific MARK IV File Management System data types and structures, to flat-file, text format that is processable on any modern computer system. The conversion processing took place at JPL's Image Processing Laboratory on an IBM 370-158 with existing software modified slightly to meet the needs of the conversion task. More than 99% of the original digital image data was successfully recovered by the conversion task. However, processing data tapes recorded before 1975 was destructive. This discovery is of critical importance to facilities responsible for maintaining digital archives since normal periodic random sampling techniques would be unlikely to detect this phenomenon, and entire data sets could be wiped out in the act of generating seemingly positive sampling results. Reccomended follow-on activities are also included

    Geomagnetically Trapped Radiation Produced by a High-Altitude Nuclear Explosion on July 9, 1962

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    Geomagnetically trapped radiation produced by a high altitude nuclear explosio

    Composite fermions from the algebraic point of view

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    Composite fermion wavefuctions have been used to describe electrons in a strong magnetic field. We show that the polynomial part of these wavefunctions can be obtained by applying a normal ordered product of suitably defined annihilation and creation operators to an even power of the Vandermonde determinant, which can been considered as a kind of a non-trivial Fermi sea. In the case of the harmonic interaction we solve the system exactly in the lowest Landau level. The solution makes explicit the boson-fermion correspondence proposed recently.Comment: 11 pages 1 figur

    Pairing via Index theorem

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    This work is motivated by a specific point of view: at short distances and high energies the undoped and underdoped cuprates resemble the π\pi-flux phase of the t-J model. The purpose of this paper is to present a mechanism by which pairing grows out of the doped π\pi-flux phase. According to this mechanism pairing symmetry is determined by a parameter controlling the quantum tunneling of gauge flux quanta. For zero tunneling the symmetry is dx2−y2+idxyd_{x^2-y^2}+id_{xy}, while for large tunneling it is dx2−y2d_{x^2-y^2}. A zero-temperature critical point separates these two limits

    Experience, Culture and Reality: The Significance of Fisher Information for Understanding the Relationship between Alternative States of Consciousness and the Structures of Reality

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    The majority of the world’s cultures encourage or require members to enter alternative states of consciousness (ASC) while involved in religious rituals. The question is, why? This paper suggests an explanation for the culturally prescribed ASC from the view of Fisher information. It argues from the position, first put forward by Emile Durkheim in his magnum opus, The Elementary Forms of the Religious Life, that all religions are grounded in reality. It suggests that many of the structural elements of cultural cosmologies are similar and that the ritual induction of ASC may help to bring individual experience into greater accord with a pan-human eidetic cosmology, and thus with certain invariant attributes of reality. The necessity of this process is demonstrated by recourse to Fisher information. The paper shows how experiences generated during alternative states of consciousness may help to maintain a minimal level of realism in the interests of adaptation to what is in other respects a transcendental reality

    A pair of planets around HD 202206 or a circumbinary planet?

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    Long-term precise Doppler measurements with the CORALIE spectrograph reveal the presence of a second planet orbiting the solar-type star HD202206. The radial-velocity combined fit yields companion masses of m_2\sini = 17.4 M_Jup and 2.44 M_Jup, semi-major axes of a = 0.83 AU and 2.55 AU, and eccentricities of e = 0.43 and 0.27, respectively. A dynamical analysis of the system further shows a 5/1 mean motion resonance between the two planets. This system is of particular interest since the inner planet is within the brown-dwarf limits while the outer one is much less massive. Therefore, either the inner planet formed simultaneously in the protoplanetary disk as a superplanet, or the outer Jupiter-like planet formed in a circumbinary disk. We believe this singular planetary system will provide important constraints on planetary formation and migration scenarios.Comment: 9 pages, 14 figures, accepted in A&A, 12-May-200

    Rapidly Rotating Fermi Gases

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    We show that the density profile of a Fermi gas in rapidly rotating potential will develop prominent features reflecting the underlying Landau level like energy spectrum. Depending on the aspect ratio of the trap, these features can be a sequence of ellipsoidal volumes or a sequence of quantized steps.Comment: 4 pages, 1 postscript fil

    On the Radii of Extrasolar Giant Planets

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    We have computed evolutionary models for extrasolar planets which range in mass from 0.1 to 3.0 Jovian Masses, and which range in equilibrium temperature from 113 K to 2000 K. We present four sequences of models, designed to show the structural effects of a solid core and of internal heating due to the conversion of kinetic to thermal energy at pressures of tens of bars. The model planetary radii are intended for comparisons with radii derived from observations of transiting extrasolar planets. To provide such comparisons, we expect that of order 10 transiting planets with orbital periods less than 200 days can be detected around bright (V<10) main-sequence stars for which accurate, well-sampled radial velocity measurements can be readily accumulated. Through these observations, structural properties of the planets will be derivable, particularly for low-mass, high-temperature planets. Implications regarding the transiting companion to OGLE-TR-56 recently announced by Konacki et al. are discussed. With regard to the confirmed transiting planet, HD 209458b, we find, in accordance with other recent calculations, that models without internal heating predict a radius that is 35 percent smaller than the observed radius. We explore the possibility that HD 209458b owes its large size to dissipation of energy arising from ongoing tidal circularization of the orbit. We show that residual scatter in the current radial velocity data set for HD 209458b is consistent with the presence of an as-of-yet undetected second companion, and that further radial velocity monitoring of the star is indicated.Comment: 23 pages, 3 figures, accepted by Astrophysical Journa
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