1,166 research outputs found

    PCSYS: The optimal design integration system picture drawing system with hidden line algorithm capability for aerospace vehicle configurations

    Get PDF
    A vehicle geometric definition based upon quadrilateral surface elements to produce realistic pictures of an aerospace vehicle. The PCSYS programs can be used to visually check geometric data input, monitor geometric perturbations, and to visualize the complex spatial inter-relationships between the internal and external vehicle components. PCSYS has two major component programs. The between program, IMAGE, draws a complex aerospace vehicle pictorial representation based on either an approximate but rapid hidden line algorithm or without any hidden line algorithm. The second program, HIDDEN, draws a vehicle representation using an accurate but time consuming hidden line algorithm

    The Thread of Legislation

    Get PDF

    The Concept of Twilight in the Writings of C.S. Lewis

    Get PDF

    Lothlorien

    Get PDF

    The Thread of Legislation

    Full text link

    Selected topics in simultaneous statistical inference

    Get PDF

    Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra

    Get PDF
    We present a technique to extract radial velocity measurements from echelle spectrograph observations of rapidly rotating stars (Vsini50V\sin{i} \gtrsim 50 km s1^{-1}). This type of measurement is difficult because the line widths of such stars are often comparable to the width of a single echelle order. To compensate for the scarcity of lines and Doppler information content, we have developed a process that forward-models the observations, fitting the radial velocity shift of the star for all echelle orders simultaneously with the echelle blaze function. We use our technique to extract radial velocity measurements from a sample of rapidly rotating A- and B-type stars used as calibrator stars observed by the California Planet Survey observations. We measure absolute radial velocities with a precision ranging from 0.5-2.0 km s1^{-1} per epoch for more than 100 A- and B-type stars. In our sample of 10 well-sampled stars with radial velocity scatter in excess of their measurement uncertainties, three of these are single-lined binaries with long observational baselines. From this subsample, we present detections of two previously unknown spectroscopic binaries and one known astrometric system. Our technique will be useful in measuring or placing upper limits on the masses of sub-stellar companions discovered by wide-field transit surveys, and conducting future spectroscopic binarity surveys and Galactic space-motion studies of massive and/or young, rapidly-rotating stars.Comment: Accepted to ApJ
    corecore