6,347 research outputs found

    The Penn State - Toru\'n Centre for Astronomy Planet Search stars IV. Dwarfs and the complete sample

    Full text link
    Our knowledge of the intrinsic parameters of exoplanets is as precise as our determinations of their stellar hosts parameters. In the case of radial velocity searches for planets, stellar masses appear to be crucial. But before estimating stellar masses properly, detailed spectroscopic analysis is essential. With this paper we conclude a general spectroscopic description of the Pennsylvania-Torun Planet Search (PTPS) sample of stars. We aim at a detailed description of basic parameters of stars representing the complete PTPS sample. We present atmospheric and physical parameters for dwarf stars observed within the PTPS along with updated physical parameters for the remaining stars from this sample after the first Gaia data release. We used high resolution (R=60 000) and high signal-to-noise-ratio (S/N=150-250) spectra from the Hobby-Eberly Telescope and its High Resolution Spectrograph. Stellar atmospheric parameters were determined through a strictly spectroscopic local thermodynamic equilibrium analysis (LTE) of the equivalent widths of FeI and FeII lines. Stellar masses, ages, and luminosities were estimated through a Bayesian analysis of theoretical isochrones. We present TeffT_{eff}, loggg , [Fe/H], micrturbulence velocities, absolute radial velocities, and rotational velocities for 156 stars from the dwarf sample of PTPS. For most of these stars these are the first determinations. We refine the definition of PTPS subsamples of stars (giants, subgiants, and dwarfs) and update the luminosity classes for all PTPS stars. Using available Gaia and Hipparcos parallaxes, we redetermine the stellar parameters (masses, radii, luminosities, and ages) for 451 PTPS stars. The complete PTPS sample of 885 stars is composed of 132 dwarfs, 238 subgiants, and 515 giants, of which the vast majority are of roughly solar mass.Comment: 11 pages, 10 figures, Accepted for publication in Astronomy & Astrophysic

    Three red giants with substellar-mass companions

    Get PDF
    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

    Comparison of Grain Refinement in Selected Materials Subjected to Hydrostatic Extrusion

    Get PDF
    The subject of this study was to examine and compare the impact of intense hydrostatic extrusion on grain refinement in three different alloys: duplex stainless steel, commercially used aluminum alloy (6060) and Ag-Cu12 alloy. As a result of the process grain sizes from 370 nm to 90 nm were obtained in aluminum and duplex steel. To analyze the of hydrostatic on mechanical properties tensile tests were also carried out. The highest grain refinement (70 nm) and yield strength increase (over 300%) was observed in duplex steel af-ter hydrostatic extrusion. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3560

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

    Full text link
    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&

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

    Full text link
    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

    Full text link
    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

    A novel approach to crystallisation of nanodispersible microparticles by spray drying for improved tabletability

    Get PDF
    YesHigh-dose API powders which are to be tableted by direct compression should have high compactibility and compressibility. This note reports on a novel approach to the manufacture of crystalline powders intended for direct compaction with improved compactibility and compressibility properties. The poorly compactable API, chlorothiazide, was spray dried from a water/acetone solvent mix producing additive-free nanocrystalline microparticles (NCMPs) of median particle size 3.5 μm. Tablets compacted from NCMPs had tensile strengths ranging from 0.5 to 4.6 MPa (compared to 0.6–0.9 MPa for tablets of micronised CTZ) at compression forces ranging from 6 kN to 13 kN. NCMP tablets also had high porosities (34–20%) and large specific surface areas (4.4–4.8 m2/g). The time taken for tablets made of NCMPs to erode was not statistically longer (p > 0.05) than for tablets made of micronised CTZ. Fragmentation of NCMPs on compression was observed. The volume fraction of particles below 1 μm present in the suspension recovered after erosion of NCMP tablets was 34.8 ± 3.43%, while no nanosized particles were detected in the slurry after erosion of compacted micronised CTZ.Solid State Pharmaceutical Cluster (SSPC), supported by Science Foundation Ireland under grant number 07/SRC/B1158

    Digital topoclimatic maps of Warsaw

    Get PDF
    Cyfrowe mapy topoklimatyczne Warszawy są efektem pierwszego etapu badań mającego na celu stworzenie bazy danych o środowisku fizyczno-geograficznym tej aglomeracji. Przy tworzeniu bazy danych zastosowano metody GIS. Wykonano mapy elementów meteorologicznych (temperatury powietrza, prędkości wiatru i całkowitego promieniowania słonecznego) oraz mapy zanieczyszczenia powietrza. Przy zastosowaniu modelu MENEX obliczono ilość ciepła zmagazynowanego przez organizm człowieka i promieniowania słonecznego pochłoniętego przez człowieka. W końcowym etapie wykonano syntetyczne mapy, np. obciążenia cieplnego człowieka, topoklimatyczną i biotopoklimatyczną.Digital topoclimatic maps of Warsaware the effect of the first step of the studies dealing with creation of the data base of physico-geographical environment of this agglomeration. GIS methods are used in this purpose. At present there were made basic maps of meteorological elements (air temperature, wind speed and global solar radiation) as well as air pollution maps. With the use of the MENEX model there were calculated maps of net heat storage of the human organism and solar radiation absorbed by man. Finally some synthetic maps were made e.g. heat load of man, topoclimatic and biotopoclimatic (which takes into account heat load of man and air pollution)
    corecore