Orbital Evolution of Planets around Intermediate-Mass Giants

Around low- and intermediate-mass (1.5-3 M_sun) red giants, no planets have been found inside 0.6 AU. Such a paucity is not seen in the case of 1 M_sun main sequence stars. In this study, we examine the possibility that short-period planets were engulfed by their host star evolving off the main sequence. To do so, we have simulated the orbital evolution of planets, including the effects of stellar tide and mass loss, to determine the critical semimajor axis, a_crit, beyond which planets survive the RGB expansion of their host star. We have found that a_crit changes drastically around 2 M_sun: In the lower-mass range, a_crit is more than 1 AU, while a_crit is as small as about 0.2 AU in the higher-mass range. Comparison with measured semimajor axes of known planets suggests that there is a lack of planets that only planet engulfment never accounts for in the higher-mass range. Whether the lack is real affects our understanding of planet formation. Therefore, increasing the number of planet samples around evolved intermediate-mass stars is quite meaningful to confirm robustness of the lack of planets.Comment: 4 pages, 3 figures, Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660

Perancangan Web Perpustakaan pada SMP Taruna Bhakti Depok

The school library is a place that provides textbooks and readings for students and teachers to support the teaching and learning process. The system of borrowing and returning books in libraries still using the manual system is feared that there will be mistakes when recording book lending, the number of books available, the difficulties in finding books and what information books are available. Implementation of web-based libraries is expected to facilitate students / teachers easy to find out what books are available, librarians become more helpful in monitoring the stock of books and the process of borrowing and return of books, so as to be able to solve the problems that are feared occurred

Fractal analysis for the ULF data during the 1993 Guam earthquake to study prefracture criticality

International audienceAn extremely large earthquake (with magnitude of 8.2) happened on 8 August 1993 near the Guam island, and ultra-low-frequency (ULF) (frequency less than 1 Hz) electromagnetic fields were measured by 3-axis induction magnetometers at an observing station (with the epicentral distance of 65 km) with sampling frequency of 1 Hz. In order to study electromagnetic signature of prefracture criticality, we have undertaken the fractal (mono-fractal) analysis by means of the Higuchi's method for the ULF data during the 1993 Guam earthquake. Then, it is found that the fractal dimension exhibits five maxima 99, 75, 52, 21, and 9?4 days before the earthquake main shock, which suggests the ULF electromagnetic signature of nonlinear evolution (in the sense of self-organized criticality) taking place in the lithosphere just before the 1993 large Guam earthquake. That is, there take place step-like changes in the lithosphere during the long-term of the order of several months before the main shock

Pengaruh Model Pembelajaran Kooperatif Tipe Two Stay Two Stray (Tsts) Terhadap Hasil Belajar Siswa Pada Materi Listrik Dinamis Pada Siswa SMA

Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan model pembelajaran Kooperatif Tipe Two Stay Two Stray terhadap hasil belajar siswa pada materi Listrik Dinamis di kelas X SMA. Jenis penelitian ini adalah quasi eksperimen dengan desain penelitian adalah Two Group Pretest postest Design. Populasi penelitian seluruh siswa kelas X SMA Negeri 3 Tebing Tinggi yang terdiri 9 kelas. Sampel penelitian diambil 2 kelas yang ditentukan dengan teknik cluster random sampling yaitu kelas X-9 sebagai kelas eksperimen dan kelas X-8 sebagai kelas kontrol. Untuk menguji hipotesis digunakan uji t setelah uji prasyarat dilakukan yaitu uji normalitas dan uji homogenitas. Dari hasil penelitian nilai rata-rata pretes kelas eksperimen adalah 36,30 dan kelas kontrol 27,90. Untuk data pretes, pada pengujian normalitas di kelas eksperimen dengan L hitung = 0,1378 dan L = 0,1730, kelas kontrol dengan L = 0,1368 dan Ltabel = 0,1730, diperoleh L hitung t tabel hitung yaitu 2,326 > 2,006 dengan = 0,05 dan dk = 54, maka Ha diterima yang berarti ada perbedaan akibat pengaruh model pembelajaran Kooperatif Tipe Two Stay Two Stray dengan model pembelajaran konvensional terhadap hasil belajar siswa pada materi Listrik Dinamis di kelas X SMA Negeri 3 Tebing Tinggi T.P 2012/2013

A comparison of different fractal analyses for VHF electromagnetic emissions and their self-organization for the off-sea Miyagi-prefecture earthquake

International audienceThe VHF electromagnetic noise intensity data at several stations in the Tohoku area of Japan during the period of a rather large (with magnitude of 7.2) earthquake (Miyagi-ken oki earthquake) taken place on 16 August 2005, are analyzed by means of different fractal analysis methods, including (1) spectral slope estimation, (2) multi-fractal detrended fluctuation analysis and (3) multi-fractal wavelet transform modulus maxima method. It seems to the authors that there is no definite analysis method for the analysis of any seismogenic phenomenon, so that the only way we have to take, is to apply different methods to the same data for the detailed comparison of the results. This comparison enables us to deduce the properties commonly observed by the above methods. Because the most important feature common to these three methods, is that significant changes in fractal scaling characteristics are observed just during the earthquake (mainly before the earthquake) only at one station of Kunimi. Finally, we can come to the definite conclusion on the self-organization of VHF emissions only at one station in the present case

Planet Population Synthesis

With the increasing number of exoplanets discovered, statistical properties of the population as a whole become unique constraints on planet formation models provided a link between the description of the detailed processes playing a role in this formation and the observed population can be established. Planet population synthesis provides such a link. The approach allows to study how different physical models of individual processes (e.g., proto-planetary disc structure and evolution, planetesimal formation, gas accretion, migration, etc.) affect the overall properties of the population of emerging planets. By necessity, planet population synthesis relies on simplified descriptions of complex processes. These descriptions can be obtained from more detailed specialised simulations of these processes. The objective of this chapter is twofold: 1) provide an overview of the physics entering in the two main approaches to planet population synthesis and 2) present some of the results achieved as well as illustrate how it can be used to extract constraints on the models and to help interpret observations.Comment: 23 pages, 8 figures, accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Henning. Updated references relative to v