1,275 research outputs found

    Three red giants with substellar-mass companions

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    We present three giant stars from the ongoing Penn State-Toru\'n Planet Search with the Hobby-Eberly Telescope, which exhibit radial velocity variations that point to a presence of planetary --mass companions around them. BD+49 828 is a M=1.52±0.22M=1.52 \pm 0.22 MM_{\odot} K0 giant with a msinim sini=1.60.2+0.41.6^{+0.4}_{-0.2} MJM_{J} minimum mass companion in a=4.20.2+0.32a=4.2^{+0.32}_{-0.2} AU (2590180+3002590^{+300}_{-180}d), e=0.350.10+0.24e=0.35^{+0.24}_{-0.10} orbit. HD 95127, a logLL/LL_{\odot}=2.28±0.382.28 \pm 0.38, R=20±9R = 20\pm 9 RR_{\odot}, M=1.20±0.22M=1.20 \pm 0.22 MM_{\odot} K0 giant has a msinim sini=5.010.44+0.615.01^{+0.61}_{-0.44} MJM_{J} minimum mass companion in a=1.280.01+0.01a=1.28^{+0.01}_{-0.01} AU (4825+5482^{+5}_{-5}d), e=0.110.06+0.15e=0.11^{+0.15}_{-0.06} orbit. Finally, HD 216536, is a M=1.36±0.38M=1.36 \pm 0.38 MM_{\odot} K0 giant with a msini=1.470.12+0.20m sin i=1.47^{+0.20}_{-0.12} MJM_{J} minimum mass companion in a=0.6090.002+0.002a=0.609^{+0.002}_{-0.002} AU (148.60.7+0.7148.6^{+0.7}_{-0.7}d), e=0.380.10+0.12e=0.38^{+0.12}_{-0.10} orbit. Both, HD 95127 b and HD 216536 b in their compact orbits, are very close to the engulfment zone and hence prone to ingestion in the near future. BD+49 828 b is among the longest period planets detected with the radial velocity technique until now and it will remain unaffected by stellar evolution up to a very late stage of its host. We discuss general properties of planetary systems around evolved stars and planet survivability using existing data on exoplanets in more detail.Comment: 47 pages, 11 figures. Accepted by Ap

    TAPAS - Tracking Advanced Planetary Systems with HARPS-N. II. Super Li-rich giant HD 107028

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    Lithium rich giant stars are rare objects. For some of them, Li enrichment exceeds abundance of this element found in solar system meteorites, suggesting that these stars have gone through a Li enhancement process. We identified a Li rich giant HD 107028 with A(Li) > 3.3 in a sample of evolved stars observed within the PennState Torun Planet Search. In this work we study different enhancement scenarios and we try to identify the one responsible for Li enrichment for HD 107028. We collected high resolution spectra with three different instruments, covering different spectral ranges. We determine stellar parameters and abundances of selected elements with both equivalent width measurements and analysis, and spectral synthesis. We also collected multi epoch high precision radial velocities in an attempt to detect a companion. Collected data show that HD 107028 is a star at the base of Red Giant Branch. Except for high Li abundance, we have not identified any other anomalies in its chemical composition, and there is no indication of a low mass or stellar companion. We exclude Li production at the Luminosity Function Bump on RGB, as the effective temperature and luminosity suggest that the evolutionary state is much earlier than RGB Bump. We also cannot confirm the Li enhancement by contamination, as we do not observe any anomalies that are associated with this scenario. After evaluating various scenarios of Li enhancement we conclude that the Li-overabundance of HD 107028 originates from Main Sequence evolution, and may be caused by diffusion process.Comment: Accepted for publication in A&

    Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. III. HD 5583 and BD+15 2375 - two cool giants with warm companions

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    Evolved stars are crucial pieces to understand the dependency of the planet formation mechanism on the stellar mass and to explore deeper the mechanism involved in star-planet interactions. Over the past ten years, we have monitored about 1000 evolved stars for radial velocity variations in search for low-mass companions under the Penn State - Torun Centre for Astronomy Planet Search program with the Hobby-Eberly Telescope. Selected prospective candidates that required higher RV precision measurements have been followed with HARPS-N at the 3.6 m Telescopio Nazionale Galileo under the TAPAS project. We aim to detect planetary systems around evolved stars to be able to build sound statistics on the frequency and intrinsic nature of these systems, and to deliver in-depth studies of selected planetary systems with evidence of star-planet interaction processes. For HD 5583 we obtained 14 epochs of precise RV measurements collected over 2313 days with the Hobby-Eberly Telescope (HET), and 22 epochs of ultra-precise HARPS-N data collected over 976 days. For BD+15 2375 we collected 24 epochs of HET data over 3286 days and 25 epochs of HARPS-S data over 902 days. We report the discovery of two planetary mass objects orbiting two evolved Red Giant stars: HD~5583 has a m sin i = 5.78 MJ_{J} companion at 0.529~AU in a nearly circular orbit (e=0.076), the closest companion to a giant star detected with the RV technique, and BD+15~2735 that with a m sin i= 1.06 MJ_{J} holds the record of the lightest planet found so far orbiting an evolved star (in a circular e=0.001, 0.576~AU orbit). These are the third and fourth planets found within the TAPAS project, a HARPS-N monitoring of evolved planetary systems identified with the Hobby-Eberly Telescope.Comment: 9 pages, 6 figures. Accepted by Astronomy and Astrophysic

    Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. V.: A Massive Jupiter orbiting the very low metallicity giant star BD+03 2562 and a possible planet around HD~103485

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    We present two evolved stars from the TAPAS (Tracking Advanced PlAnetary Systems) with HARPS-N project devoted to RV precision measurements of identified candidates within the PennState - Torun Centre for Astronomy Planet Search. Evolved stars with planets are crucial to understand the dependency of the planet formation mechanism on the mass and metallicity of the parent star and to study star-planet interactions. The paper is based on precise radial velocity (RV) measurements, for HD 103485 we collected 57 epochs over 3317 days with the Hobby-Eberly Telescope and its High Resolution Spectrograph and 18 ultra-precise HARPS-N data over 919 days. For BD+03 2562 we collected 46 epochs of HET data over 3380 days and 19 epochs of HARPS-N data over 919 days. We present the analysis of the data and the search for correlations between the RV signal and stellar activity, stellar rotation and photometric variability. Based on the available data, we interpret the RV variations measured in both stars as Keplerian motion. Both stars have masses close to Solar (1.11 and 1.14), very low metallicities ([Fe/H]=-0.50 and -0.71), and, both have Jupiter planetary mass companions (m sin i=7 and 6.4 Mj), in close to terrestrial orbits (1.4 and 1.3~au), with moderate eccentricities (e=0.34 and 0.2). However, we cannot totally exclude that the signal in the case of HD~103485 is due to rotational modulation of active regions. Based on the current data, we conclude that BD+03 2562 has a bona fide planetary companion while for HD 103485 we cannot totally exclude that the best explanation for the RV signal modulations is not the existence of a planet but stellar activity. If, the interpretation remains that both stars have planetary companions they represent systems orbiting very evolved stars with very low metallicities, a challenge to the conditions required for the formation of massive giant gas planets.Comment: Acepted A&A 12 pages, 11 figure

    Persepsi Siswa Tentang Pembelajaran Ekonomi XI Iis 1 dan 2 SMA Muhammadiyah 1 Pontianak

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    The purpose of study to determine students' perceptions about the learning economy class XI IIS 1 dan 2 SMA Muhammadiyah 1 Pontianak. The research method used is descriptive method with survey forms. This research data sources amounted to 6 students. Research shows that students assume that they understand the deliveryof content by teachers. Explanation by the teacher according to the material, students also considered the model used during the learning attractive and also coupled with examples of each explanation make students better understand, students assume media teachers use varied so as to make them more interested in learning and easier to understand the material, students also believe that teachers always give each end of evaluation in the form of lessons varies that it can also help them understand the material, as well as the motivation of teachers in each learning also makes them more viable for learing

    TAPAS IV. TYC 3667-1280-1 b - the most massive red giant star hosting a warm Jupiter

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    We present the latest result of the TAPAS project that is devoted to intense monitoring of planetary candidates that are identified within the PennState-Toru\'n planet search. We aim to detect planetary systems around evolved stars to be able to build sound statistics on the frequency and intrinsic nature of these systems, and to deliver in-depth studies of selected planetary systems with evidence of star-planet interaction processes. The paper is based on precise radial velocity measurements: 13 epochs collected over 1920 days with the Hobby-Eberly Telescope and its High-Resolution Spectrograph, and 22 epochs of ultra-precise HARPS-N data collected over 961 days. We present a warm-Jupiter (Teq=1350KT_{eq}=1350 K, m2sini=5.4±m_{2} sin i=5.4\pm0.4MJM_{J}) companion with an orbital period of 26.468 days in a circular (e=0.036e=0.036) orbit around a giant evolved (logg=3.11±0.09\log g=3.11\pm0.09, R=6.26±0.86RR=6.26\pm0.86R_{\odot}) star with M=1.87±0.17MM_{\star}=1.87\pm0.17M_{\odot}. This is the most massive and oldest star found to be hosting a close-in giant planet. Its proximity to its host (a=0.21aua=0.21au) means that the planet has a 13.9±2.0%13.9\pm2.0\% probability of transits; this calls for photometric follow-up study. This massive warm Jupiter with a near circular orbit around an evolved massive star can help set constraints on general migration mechanisms for warm Jupiters and, given its high equilibrium temperature, can help test energy deposition models in hot Jupiters.Comment: 5 pages, 3 figures, accepted by A&

    A Lattice Study of Quark and Glue Momenta and Angular Momenta in the Nucleon

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    We report a complete calculation of the quark and glue momenta and angular momenta in the proton. These include the quark contributions from both the connected and disconnected insertions. The quark disconnected insertion loops are computed with Z4Z_4 noise, and the signal-to-noise is improved with unbiased subtractions. The glue operator is comprised of gauge-field tensors constructed from the overlap operator. The calculation is carried out on a 163×2416^3 \times 24 quenched lattice at β=6.0\beta = 6.0 for Wilson fermions with κ=0.154,0.155\kappa=0.154, 0.155, and 0.15550.1555 which correspond to pion masses at 650,538650, 538, and 478478~MeV, respectively. The chirally extrapolated uu and dd quark momentum/angular momentum fraction is found to be 0.64(5)/0.70(5)0.64(5)/0.70(5), the strange momentum/angular momentum fraction is 0.024(6)/0.023(7)0.024(6)/0.023(7), and that of the glue is 0.33(6)/0.28(8)0.33(6)/0.28(8). The previous study of quark spin on the same lattice revealed that it carries a fraction of 0.25(12)0.25(12) of proton spin. The orbital angular momenta of the quarks are then obtained from subtracting the spin from their corresponding angular momentum components. We find that the quark orbital angular momentum constitutes 0.47(13)0.47(13) of the proton spin with almost all of it coming from the disconnected insertions.Comment: Renormalization section is expanded to include more details. There are slight changes in the final numbers. A few modification and corrections are made in the rest of the tex

    Perancangan Expert System Untuk Troubleshooting Mesin Dengan Decision Table(studi Kasus Di PT. Adi Putro Wirasejati)

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    PT. Adi Putro Wirasejati merupakan salah satu karoseri yang bergerak dalam bidang pembentukan body kendaraan bus dan minibus. Perusahaan memiliki kendala yaitu terhambatnya proses produksi karena beberapa kali mesin produksi tidak dapat berfungsi dan harus dilakukan kegiatan perawatan. Departemen maintenance yang memiliki 11 karyawan menangani semua mesin dalam lini produksi yang berjumlah cukup besar. Hal ini menyebabkan terjadinya beberapa kesalahan diagnosa kerusakan yang menimbulkan kesalahan dalam pengambilan keputusan, sehingga menyebabkan adanya perhentian lini produksi akibat dari bottleneck mesin yang rusak. Dalam perawatan mesin, diperlukan tenaga ahli di bidang mesin yang harus siap sedia bila terjadi masalah atau kerusakan. Akan tetapi, pakar atau orang ahli di bidang mesin tidak selalu siap sedia 24 jam sehari. Oleh karena itu dibutuhkan prototype yang dapat menyimpan pengetahuan pakar dan melakukan konsultasi perbaikan mesin. Penelitian ini menggunakan metode Expert System sebagai penalaran untuk mencari rekomendasi perbaikan, dan Decision Table sebagai tools untuk menyimpan pengetahuan kerusakan mesin yang digunakan oleh expert system dalam mencari rekomendasi perbaikan. Tahap pertama yang dilakukan adalah melihat sistem troubleshooting yang bekerja pada departemen maintenance. Dilanjutkan identifikasi permasalahan lambatnya penanganan kerusakan mesin, selanjutnya merancang desain sistem baru yaitu expert system untuk membantu mencari rekomendasi perbaikan kerusakan mesin. Setelah merancang sistem maka dibuat program expert system sesuai yang dirancang.Setelah pembuatan program maka dapat disimpulkan konsultasi pada sistem expert system, kerusakan mesin mampu mempercepat performansi kinerja departemen maintenance dalam melaksanakan perbaikan kerusakan mesin. Bila sistem lama dalam mencari rekomendasi kerusakan mesin membutuhkan waktu antara 15-45 menit bahkan lebih, pada sistem baru akan memberikan rekomendasi dalam waktu kurang lebih 5 menit dengan rekomendasi kerusakan yang tepat sehingga tidak terjadi salah pendugaan. Pengetahuan pakar sudah tersimpan dalam sistem sehingga mempermudah kapan saja berkonsultasi, sistem dapat beroperasi selama 7 hari dalam seminggu dan 365 hari dalam setahun. Selain itu, prototype expert system kerusakan mesin mampu memberikan informasi basis pengetahuan tentang kerusakan mesin juga dapat digunakan sebagai pelatihan untuk menangani kerusakan mesin

    Fractal Inspired Models of Quark and Gluon Distributions and Longitudinal Structure Function FL(x, Q2) at small x

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    In recent years, Fractal Inspired Models of quark and gluon densities at small x have been proposed. In this paper, we investigate longitudinal structure function F-L (x, Q2) within this approach. We make predictions using the QCD based approximate relation between the longitudinal structure function and the gluon density. As the Altarelli-Martinelli equation for the longitudinal structure function cannot be applied to Model I due to the presence of a singularity in the Bjorken x-space we consider Model II only. The qualitative feature of the prediction of Model II is found to be compatible with the QCD expectation.Comment: 11 pages, 4 figures, Accepted for publication on 10-07-2010 in Indian Journal of Physic
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