4,272 research outputs found

    Toward a Deterministic Model of Planetary Formation VII: Eccentricity Distribution of Gas Giants

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    The ubiquity of planets and diversity of planetary systems reveal planet formation encompass many complex and competing processes. In this series of papers, we develop and upgrade a population synthesis model as a tool to identify the dominant physical effects and to calibrate the range of physical conditions. Recent planet searches leads to the discovery of many multiple-planet systems. Any theoretical models of their origins must take into account dynamical interaction between emerging protoplanets. Here, we introduce a prescription to approximate the close encounters between multiple planets. We apply this method to simulate the growth, migration, and dynamical interaction of planetary systems. Our models show that in relatively massive disks, several gas giants and rocky/icy planets emerge, migrate, and undergo dynamical instability. Secular perturbation between planets leads to orbital crossings, eccentricity excitation, and planetary ejection. In disks with modest masses, two or less gas giants form with multiple super-Earths. Orbital stability in these systems is generally maintained and they retain the kinematic structure after gas in their natal disks is depleted. These results reproduce the observed planetary mass-eccentricity and semimajor axis-eccentricity correlations. They also suggest that emerging gas giants can scatter residual cores to the outer disk regions. Subsequent in situ gas accretion onto these cores can lead to the formation of distant (> 30AU) gas giants with nearly circular orbits.Comment: 54 pages, 14 Figures; accepted for publication in Astrophysical Journa

    How Do Nonlinear Voids Affect Light Propagation ?

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    Propagation of light in a clumpy universe is examined. As an inhomogeneous matter distribution, we take a spherical void surrounded by a dust shell where the ``lost mass'' in the void is compensated by the shell. We study how the angular-diameter distance behaves when such a structure exists. The angular-diameter distance is calculated by integrating the Raychaudhuri equation including the shear. An explicit expression for the junction condition for the massive thin shell is calculated. We apply these results to a dust shell embedded in a Friedmann universe and determine how the distance-redshift relation is modified compared with that in the purely Friedmann universe. We also study the distribution of distances in a universe filled with voids. We show that the void-filled universe gives a larger distance than the FRW universe by ∼5\sim 5% at z∼1z \sim 1 if the size of the void is ∼5\sim 5% of the Horizon radius.Comment: To appear in Prog. Theor. Phys. 10

    Tipe-tipe Budaya Perusahaan dan Pengaruhnya terhadap Kepuasan Kerja Pegawai Telkom Uner III Bandung

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    Formation of Hot Planets by a combination of planet scattering, tidal circularization, and Kozai mechanism

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    We have investigated the formation of close-in extrasolar giant planets through a coupling effect of mutual scattering, Kozai mechanism, and tidal circularization, by orbital integrations. We have carried out orbital integrations of three planets with Jupiter-mass, directly including the effect of tidal circularization. We have found that in about 30% runs close-in planets are formed, which is much higher than suggested by previous studies. We have found that Kozai mechanism by outer planets is responsible for the formation of close-in planets. During the three-planet orbital crossing, the Kozai excitation is repeated and the eccentricity is often increased secularly to values close enough to unity for tidal circularization to transform the inner planet to a close-in planet. Since a moderate eccentricity can remain for the close-in planet, this mechanism may account for the observed close-in planets with moderate eccentricities and without nearby secondary planets. Since these planets also remain a broad range of orbital inclinations (even retrograde ones), the contribution of this process would be clarified by more observations of Rossiter-McLaughlin effects for transiting planets.Comment: 15 pages, 16 figures, Accepted for publication in Ap

    Migrasi Simbolik Wacana Kuasa Tubuh: Menguak Wacana Tubuh Dalam Ode Untuk Leopold Von Sacher-Masoch Karya Dinar Rahayu

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    The presence of Indonesian women writers with the dominant discourse of the power of body, presenting the pros and cons that would not go over. Female body is the language of women that can be poured through the writing of literary works. Helene Cixous brought the spirit of "writing the body" to motivate women authors to express himself through written discourse, which so far has been dominated by men. Cixous spirit is also promoted by Dinar Rahayu appear in the novel Ode untuk Leopold Von Sacher-Masoch. Dinar Rahayu voicing complexity of urban women's voices in this novel through several migration symbolic of the power of the female body. Migration is enriched by the presence of symbolic power in a sound body of Greek and Scandinavian mythology and Leopold voices in his work Venus in Furs. Through in-depth reading on the symbolic migration brought to the Ode untuk Leopold Von Sacher-Masoch through the voices of the characters and the particularities of naration techniques can be seen that this novel (as well as other sexist novels) is not merely a commodity that exploit sexuality pornography but rather an attempt to author urban female voices will be the "body power". This study uses content analysis method that begins with the reading of literature, heuristic and hermeneutic, and take advantage of intertextuality approach

    Comparison of toroidal viscosity with neoclassical theory

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    Toroidal rotation profiles are measured with charge exchange spectroscopy for a plasma heated with tangential neutral beam injection (NBI) in the Compact Helical System (CHS) heliotron/torsatron device [Ida et al., Phys. Rev. Lett. 67, 58 (1991)] to estimate the toroidal viscosity. The toroidal viscosity derived from the toroidal rotation velocity shows good agreement with the neoclassical toroidal viscosity plus the perpendicular viscosity ( [perpendicular]=2 m^2/s)

    The Readiness of English Communication Skills of Mataram Tourism Vocational College Students for ASEAN Economic Community

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    The purpose of this study was to find out the readiness of English communication skills of tourism students at Mataram Tourism Vocational College to enter the ASEAN Economic Community era. The scope of this study includes students from three tourism study programs, namely diploma 3 programs in hotel and hospitality, diploma 3 tours and travel and bachelor program in tourism. A total of 110 respondents were used in this study. Four English communication skills including listening, speaking, reading, and writing are measured using questionnaires as instruments for collecting data. Statistical analysis includes percentages, averages, and standard deviations. The research findings revealed that Tourism students at STP Mataram need to develop and improve their skills in English communication, especially listening and speaking which is a skill needed to communicate with foreigners, especially in NTB. From the four skills of language, STP Mataram student Language skills are not ready to communicate using English, 30% respondents answered that they have not been able or disagree from the questionnaire

    Analysis Of Students' Ability In Using English For Taking Order Procedure In Restaurant

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    The aim of this study to analyze students' English speaking skills in conducting taking orders procedure in restaurants. This study is conducted in order to overcome the problems encountered by the students in speaking activities in taking orders. To measure the ability of students in speaking English in taking orders, the researchers observed the procedures that the students did not perform and measure the students' competence of English language. Samples of this study are the fourth semester students in Hospitality courses Diploma Degree of Mataram Tourism Institute in Academic Year 2018/2019. The results of this study indicated that the level of completeness of the procedure in taking student orders in STP Mataram is in average. More than 50% students have conducted the appropriate procedure when taking orders in using English. From the result of data analysis in measuring the students' competence in speaking English, the mean score is 78.90 with standard deviation is 12.14. From the result, it is converted and get score 3.1. The score showed that the ability of English students from 40 students in STP Mataram classified as Good Criteria
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