2 research outputs found

    Predicting glare from daylight through microstructures solar control systems using matrix-based simulation methods in Radiance

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    In this study the five-phase method and a parallelized invocation of evalglare has been used, to evaluate the performance of a microstructure and a Low-E window w/wo external blind, in terms of glare. The first part of the results investigates how Bidirectional-Scattering-Distribution-Functions, BSDF, and aBSDF (Aperture BSDF) properties bias the predicted glare through a microstructure, linking BSDF rank to saturation glare and resolution to contrast glare. The investigation found a combination of correct rank, low resolution and peak extraction (aBSDF) to be the best trade-off between speed and accuracy. The later comparison found none of the investigated systems to be sufficient glare protection. The microstructure was found to outperform the external blinds, using the current shading schedule (9% peak difference in occupied hours exceeding a DGP of 0.45)

    A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS

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    © 2019. The American Astronomical Society. All rights reserved.. We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V = 8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 ÎŒHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2 minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (R∗ = 2.943 ± 0.064 Ro), mass (M∗ = 1.212 ± 0.074 Mo), and age (4.9 ± 1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a "hot Saturn" (Rp = 9.17 ± 0.33 R⊕) with an orbital period of ∌14.3 days, irradiance of F = 343 ± 24 F⊕, and moderate mass (Mp = 60.5 ± 5.7 M⊕) and density (ρp = 0.431 ± 0.062 g cm-3). The properties of HD 221416 b show that the host-star metallicity-planet mass correlation found in sub-Saturns (4-8 R⊕) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ∌15%, HD 221416 b is one of the best characterized Saturn-size planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology
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