4,366 research outputs found

    A Spin-Orbit Alignment for the Hot Jupiter HATS-3b

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    We have measured the alignment between the orbit of HATS-3b (a recently discovered, slightly inflated Hot Jupiter) and the spin-axis of its host star. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The sky-projected spin-orbit angle of λ=3±25\lambda = 3\pm25^{\circ} was determined from spectroscopic measurements of Rossiter-McLaughlin effect. This is the first exoplanet discovered through the HATSouth transit survey to have its spin-orbit angle measured. Our results indicate that the orbital plane of HATS-3b is consistent with being aligned to the spin axis of its host star. The low obliquity of the HATS-3 system, which has a relatively hot mid F-type host star, agrees with the general trend observed for Hot Jupiter host stars with effective temperatures >6250>6250K to have randomly distributed spin-orbit angles.Comment: 13 pages. Accepted for publication in the Astrophysical Journa

    An adaptive pseudo-spectral method for reaction diffusion problems

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    The spectral interpolation error was considered for both the Chebyshev pseudo-spectral and Galerkin approximations. A family of functionals I sub r (u), with the property that the maximum norm of the error is bounded by I sub r (u)/J sub r, where r is an integer and J is the degree of the polynomial approximation, was developed. These functionals are used in the adaptive procedure whereby the problem is dynamically transformed to minimize I sub r (u). The number of collocation points is then chosen to maintain a prescribed error bound. The method is illustrated by various examples from combustion problems in one and two dimensions

    SuperLupus: A Deep, Long Duration Transit Survey

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    SuperLupus is a deep transit survey monitoring a Galactic Plane field in the Southern hemisphere. The project is building on the successful Lupus Survey, and will double the number of images of the field from 1700 to 3400, making it one of the longest duration deep transit surveys. The immediate motivation for this expansion is to search for longer period transiting planets (5-8 days) and smaller radii planets. It will also provide near complete recovery for the shorter period planets (1-3 days). In March, April, and May 2008 we obtained the new images and work is currently in progress reducing these new data.Comment: 3 pages, 2 figures, to appear in the Proceedings of IAU Symposium 253, 2008: Transiting Planet

    Effective Improvement of Symptoms in Patients with Acute Migraine by GR43175 Administered in Dispersible Tablets

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    GR43175, a selective 5-HT1-like agonist, was administered as oral dispersible tablets in an open, uncontrolled dose-ranging study to assess its efficacy as an agent for acute migraine. Nine patients, all with well established attacks, were assessed for changes in severity of headache and associated symptoms over 2 h. Drug absorption was compared during and between attacks in five patients. Doses of 140 mg and 280 mg resulted in complete relief of all symptoms within 2 h. Treatment was well tolerated in all patients

    Examining the broadband emission spectrum of WASP-19b: A new z band eclipse detection

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    WASP-19b is one of the most irradiated hot-Jupiters known. Its secondary eclipse is the deepest of all transiting planets, and has been measured in multiple optical and infrared bands. We obtained a z band eclipse observation, with measured depth of 0.080 +/- 0.029 %, using the 2m Faulkes Telescope South, that is consistent with the results of previous observations. We combine our measurement of the z band eclipse with previous observations to explore atmosphere models of WASP-19b that are consistent with the its broadband spectrum. We use the VSTAR radiative transfer code to examine the effect of varying pressure-temperature profiles and C/O abundance ratios on the emission spectrum of the planet. We find models with super-solar carbon enrichment best match the observations, consistent with previous model retrieval studies. We also include upper atmosphere haze as another dimension in the interpretation of exoplanet emission spectra, and find that particles <0.5 micron in size are unlikely to be present in WASP-19b.Comment: 10 pages, 8 figures, 2 tables, accepted for publication in Ap

    Grasping the concept of personal property.

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    The concept of property is integral to personal and societal development, yet understanding of the cognitive basis of ownership is limited. Objects are the most basic form of property, so our physical interactions with owned objects may elucidate nuanced aspects of ownership. We gave participants a coffee mug to decorate, use and keep. The experimenter also designed a mug of her own. In Experiment 1, participants performed natural lifting actions with each mug. Participants lifted the Experimenter's mug with greater care, and moved it slightly more towards the Experimenter, while they lifted their own mug more forcefully and drew it closer to their own body. In Experiment 2, participants responded to stimuli presented on the mug handles in a computer-based stimulus-response compatibility task. Overall, participants were faster to respond in trials in which the handles were facing in the same direction as the response location compared to when the handles were facing away. The compatibility effect was abolished, however, for the Experimenter's mug - as if the action system is blind to the potential for action towards another person's property. These findings demonstrate that knowledge of the ownership status of objects influences visuomotor processing in subtle and revealing ways

    Room temperature magneto-optic effect in silicon light-emitting diodes

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    In weakly spin-orbit coupled materials, the spin-selective nature of recombination can give rise to large magnetic-field effects, for example on electro-luminescence from molecular semiconductors. While silicon has weak spin-orbit coupling, observing spin-dependent recombination through magneto-electroluminescence is challenging due to the inefficiency of emission due to silicon's indirect band-gap, and to the difficulty in separating spin-dependent phenomena from classical magneto-resistance effects. Here we overcome these challenges to measure magneto-electroluminescence in silicon light-emitting diodes fabricated via gas immersion laser doping. These devices allow us to achieve efficient emission while retaining a well-defined geometry thus suppressing classical magnetoresistance effects to a few percent. We find that electroluminescence can be enhanced by up to 300\% near room temperature in a seven Tesla magnetic field showing that the control of the spin degree of freedom can have a strong impact on the efficiency of silicon LEDs

    Ground-based photometry of the 21-day Neptune HD106315c

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    Space-based transit surveys such as K2 and TESS allow the detection of small transiting planets with orbital periods beyond 10 days. Few of these warm Neptunes are currently known around stars bright enough to allow for detailed follow-up observations dedicated to their atmospheric characterization. The 21-day period and 3.95 RR_\oplus planet HD106315c has been discovered based on the observation of two of its transits by K2. We have observed HD106315 using the 1.2m Euler telescope equipped with the EulerCam camera on two instances to confirm the transit using broad band photometry and refine the planetary period. Based on two observed transits of HD106315c, we detect its \sim1 mmag transit and obtain a precise measurement of the planetary ephemerids, which are critical for planning further follow-up observations. We have used the attained precision together with the predicted yield from the TESS mission to evaluate the potential for ground-based confirmation of Neptune-sized planets found by TESS. We find that 1-meter-class telescopes on the ground equipped with precise photometers could substantially contribute to the follow-up of 162 TESS candidates orbiting stars with magnitudes of V14V \leq 14. Out of these, 74 planets orbit stars with V12V \leq 12 and 12 planets orbit V10V \leq 10, which makes these candidates high-priority objects for atmospheric characterization with high-end instrumentation.Comment: Published in A&A letters, 4 pages, 3 figure

    A Nearly Polar Orbit for the Extrasolar Hot Jupiter WASP-79b

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    We report the measurement of a spin-orbit misalignment for WASP-79b, a recently discovered, bloated transiting hot Jupiter from the WASP survey. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. We have used the Rossiter-McLaughlin effect to determine the sky-projected spin-orbit angle to be lambda = -106+19-13 degrees. This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet -- the planet being in a nearly polar orbit. WASP-79 is consistent with other stars that have Teff > 6250K and host hot Jupiters in spin-orbit misalignment.Comment: 8 pages, 2 figures, in press ApJL (accepted 2 August 2013
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