105 research outputs found

    Utility of Portable Breath Alcohol Testers for Drunken Driving Offenders

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    Participants in two countermeasures programs for drunken drivers found portable breath alcohol testers useful in making decisions about driving after drinking and said they would continue to use them if they were commercially available

    VLBI and Archival VLA and WSRT Observations of the GRB 030329 Radio Afterglow

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    We present VLBI and archival Karl G. Jansky Very Large Array (VLA) and Westerbork Synthesis Radio Telescope (WSRT) observations of the radio afterglow from the gamma-ray burst (GRB) of 2003 March 29 (GRB 030329) taken between 672 and 2032 days after the burst. The EVLA and WSRT data suggest a simple power law decay in the flux at 5 GHz, with no clear signature of any rebrightening from the counter jet. We report an unresolved source at day 2032 of size 1.18±0.131.18\pm0.13 mas, which we use in conjunction with the expansion rate of the burst to argue for the presence of a uniform, ISM-like circumburst medium. We develop a semi-analytic method to model gamma-ray burst afterglows, and apply it to the 5 GHz light curve to perform burst calorimetry. A limit of <0.067< 0.067 mas yr1^{-1} is placed on the proper motion, supporting the standard afterglow model for gamma-ray bursts.Comment: 24 pages, 5 figure

    Gravity-darkening Analysis of the Misaligned Hot Jupiter MASCARA-4 b

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    MASCARA-4 b is a hot Jupiter in a highly misaligned orbit around a rapidly rotating A3V star that was observed for 54 days by the Transiting Exoplanet Survey Satellite (TESS). We perform two analyses of MASCARA-4 b using a stellar gravity-darkened model. First, we measure MASCARA-4 b's misaligned orbital configuration by modeling its TESS photometric light curve. We take advantage of the asymmetry in MASCARA-4 b's transit due to its host star's gravity-darkened surface to measure MASCARA-4 b's true spin–orbit angle to be 104°+7°-13°. We also detect a ~4σ secondary eclipse at 0.491 ± 0.007 orbital phase, proving that the orbit is slightly eccentric. Second, we model MASCARA-4 b's insolation including gravity darkening and find that the planet's received X-ray and ultraviolet flux varies by 4% throughout its orbit. MASCARA-4 b's short-period, polar orbit suggests that the planet likely underwent dramatic orbital evolution to end up in its present-day configuration and that it receives a varying stellar irradiance that perpetually forces the planet out of thermal equilibrium. These findings make MASCARA-4 b an excellent target for follow-up characterization to better understand the orbital evolution and present-day environment of planets around high-mass stars

    KELT-9 b's Asymmetric TESS Transit Caused by Rapid Stellar Rotation and Spin-Orbit Misalignment

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    KELT-9 b is an ultra hot Jupiter transiting a rapidly rotating, oblate early-A-type star in a polar orbit. We model the effect of rapid stellar rotation on KELT-9 b's transit light curve using photometry from the Transiting Exoplanet Survey Satellite (\tess) to constrain the planet's true spin-orbit angle and to explore how KELT-9 b may be influenced by stellar gravity darkening. We constrain the host star's equatorial radius to be 1.089±0.0171.089\pm0.017 times as large as its polar radius and its local surface brightness to vary by 38\sim38\% between its hot poles and cooler equator. We model the stellar oblateness and surface brightness gradient and find that it causes the transit light curve to lack the usual symmetry around the time of minimum light. We take advantage of the light curve asymmetry to constrain KELT-9 b's true spin orbit angle (8711+10{87^\circ}^{+10^\circ}_{-11^\circ}), agreeing with \citet{gaudi2017giant} that KELT-9 b is in a nearly polar orbit. We also apply a gravity darkening correction to the spectral energy distribution model from \citet{gaudi2017giant} and find that accounting for rapid rotation gives a better fit to available spectroscopy and yields a more reliable estimate for the star's polar effective temperature.Comment: Accepted for Publication in ApJ. arXiv admin note: text overlap with arXiv:1911.0502

    TOI 540 b: A Planet Smaller than Earth Orbiting a Nearby Rapidly Rotating Low-mass Star

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    We present the discovery of TOI 540 b, a hot planet slightly smaller than Earth orbiting the low-mass star 2MASS J05051443-4756154. The planet has an orbital period of P=1.239149P = 1.239149 days (±\pm 170 ms) and a radius of r=0.903±0.052REarthr = 0.903 \pm 0.052 R_{\rm Earth}, and is likely terrestrial based on the observed mass-radius distribution of small exoplanets at similar insolations. The star is 14.008 pc away and we estimate its mass and radius to be M=0.159±0.014MSunM = 0.159 \pm 0.014 M_{\rm Sun} and R=0.1895±0.0079RSunR = 0.1895 \pm 0.0079 R_{\rm Sun}, respectively. The star is distinctive in its very short rotational period of Prot=17.4264+/0.0094P_{\rm rot} = 17.4264 +/- 0.0094 hours and correspondingly small Rossby number of 0.007 as well as its high X-ray-to-bolometric luminosity ratio of LX/Lbol=0.0028L_X / L_{\rm bol} = 0.0028 based on a serendipitous XMM-Newton detection during a slew operation. This is consistent with the X-ray emission being observed at a maximum value of LX/Lbol103L_X / L_{\rm bol} \simeq 10^{-3} as predicted for the most rapidly rotating M dwarfs. TOI 540 b may be an alluring target to study atmospheric erosion due to the strong stellar X-ray emission. It is also among the most accessible targets for transmission and emission spectroscopy and eclipse photometry with JWST, and may permit Doppler tomography with high-resolution spectroscopy during transit. This discovery is based on precise photometric data from TESS and ground-based follow-up observations by the MEarth team.Comment: 18 pages, 7 figures. Accepted for publication in The Astronomical Journa

    Quantum efficiency measurement of the Transiting Exoplanet Survey Satellite (TESS) CCD detectors

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    Very precise on-ground characterization and calibration of TESS CCD detectors will significantly assist in the analysis of the science data from the mission. An accurate optical test bench with very high photometric stability has been developed to perform precise measurements of the absolute quantum efficiency. The setup consists of a vacuum dewar with a single MIT Lincoln Lab CCID-80 device mounted on a cold plate with the calibrated reference photodiode mounted next to the CCD. A very stable laser-driven light source is integrated with a closed-loop intensity stabilization unit to control variations of the light source down to a few parts-per-million when averaged over 60 s. Light from the stabilization unit enters a 20 inch integrating sphere. The output light from the sphere produces near-uniform illumination on the cold CCD and on the calibrated reference photodiode inside the dewar. The ratio of the CCD and photodiode signals provides the absolute quantum efficiency measurement. The design, key features, error analysis, and results from the test campaign are presented.United States. National Aeronautics and Space Administration (contract number NNG14FC03C

    TOI-431/HIP 26013: A super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

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    We present the bright (Vmag = 9.12), multiplanet system TOI-431, characterized with photometry and radial velocities (RVs). We estimate the stellar rotation period to be 30.5 ± 0.7 d using archival photometry and RVs. Transiting Exoplanet Survey Satellite (TESS) objects of Interest (TOI)-431 b is a super-Earth with a period of 0.49 d, a radius of 1.28 ± 0.04 R, a mass of 3.07 ± 0.35 M, and a density of 8.0 ± 1.0 g cm-3; TOI-431 d is a sub-Neptune with a period of 12.46 d, a radius of 3.29 ± 0.09 R, a mass of 9.90+1.53-1.49 M, and a density of 1.36 ± 0.25 g cm-3. We find a third planet, TOI-431 c, in the High Accuracy Radial velocity Planet Searcher RV data, but it is not seen to transit in the TESS light curves. It has an Msin i of 2.83+0.41-0.34 M, and a period of 4.85 d. TOI-431 d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterization, while the super-Earth TOI-431 b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431 b is a prime TESS discovery for the study of rocky planet phase curves.Fil: Osborn, Ares. University of Warwick; Reino UnidoFil: Armstrong, David J. University of Warwick; Reino UnidoFil: Cale, Bryson. George Mason University; Estados UnidosFil: Brahm, Rafael. Universidad Adolfo Ibañez; Chile. Instituto de Astrofísica; ChileFil: Wittenmyer, Robert A. University Of Southern Queensland; AustraliaFil: Dai, Fei. Division Of Geological And Planetary Sciences; Estados UnidosFil: Crossfield, Ian J. M. University of Kansas; Estados UnidosFil: Bryant, Edward M. University of Warwick; Reino UnidoFil: Adibekyan, Vardan. Universidad de Porto; PortugalFil: Cloutier, Ryan. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Collins, Karen A. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Delgado Mena, E.. Universidad de Porto; PortugalFil: Fridlund, Malcolm. Leiden University; Países Bajos. Chalmers University of Technology; SueciaFil: Hellier, Coel. Keele University; Reino UnidoFil: Howell, Steve B. NASA Ames Research Center; Estados UnidosFil: King, George W. University of Warwick; Reino UnidoFil: Lillo Box, Jorge. Consejo Superior de Investigaciones Científicas. Centro de Astrobiología; EspañaFil: Otegi, Jon. Universidad de Ginebra; Suiza. Universitat Zurich; SuizaFil: Sousa, S.. Universidad de Porto; PortugalFil: Stassun, Keivan G. Vanderbilt University; Estados UnidosFil: Matthews, Elisabeth C. Universidad de Ginebra; Suiza. Massachusetts Institute of Technology; Estados UnidosFil: Ziegler, Carl. University of Toronto; CanadáFil: Ricker, George. Massachusetts Institute of Technology; Estados UnidosFil: Vanderspek, Roland. Massachusetts Institute of Technology; Estados UnidosFil: Latham, David W. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Seager, S.. Massachusetts Institute of Technology; Estados UnidosFil: Winn, Joshua N.. University of Princeton; Estados UnidosFil: Jenkins, Jon M. NASA Ames Research Center; Estados UnidosFil: Acton, Jack S. University of Leicester; Reino UnidoFil: Addison, Brett C. University Of Southern Queensland; AustraliaFil: Diaz, Rodrigo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Físicas. - Universidad Nacional de San Martín. Instituto de Ciencias Físicas; Argentin
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