18 research outputs found
Angioplasty in acute middle cerebral artery stroke due to atrial fibrillation selected by CT perfusion: a case report
We report the experience of a case of acute stroke in a patient affected by Rendu Osler syndrome and atrial fibrillation. The combination of dynamic computerized tomography perfusion scans and the use of a high-compliance balloon allowed increasing the treatment window for intra-arterial recanalization over 6 h after stroke onset in a patient with middle cerebral artery occlusion
The thermal emission of the exoplanets WASP-1b and WASP-2b
We present a comparative study of the thermal emission of the transiting exoplanets WASP-1b and WASP-2b using the Spitzer Space Telescope. The two planets have very similar masses but suffer different levels of irradiation and are predicted to fall either side of a sharp transition between planets with and without hot stratospheres. WASP-1b is one of the most highly irradiated planets studied to date. We measure planet/star contrast ratios in all four of the IRAC bands for both planets (3.6-8.0um), and our results indicate the presence of a strong temperature inversion in the atmosphere of WASP-1b, particularly apparent at 8um, and no inversion in WASP-2b. In both cases the measured eclipse depths favor models in which incident energy is not redistributed efficiently from the day side to the night side of the planet. We fit the Spitzer light curves simultaneously with the best available radial velocity curves and transit photometry in order to provide updated measurements of system parameters. We do not find significant eccentricity in the orbit of either planet, suggesting that the inflated radius of WASP-1b is unlikely to be the result of tidal heating. Finally, by plotting ratios of secondary eclipse depths at 8um and 4.5um against irradiation for all available planets, we find evidence for a sharp transition in the emission spectra of hot Jupiters at an irradiation level of 2 x 10^9 erg/s/cm^2. We suggest this transition may be due to the presence of TiO in the upper atmospheres of the most strongly irradiated hot Jupiters
The thermal emission of the exoplanets WASP-1b and WASP-2b
We present a comparative study of the thermal emission of the transiting
exoplanets WASP-1b and WASP-2b using the Spitzer Space Telescope. The two
planets have very similar masses but suffer different levels of irradiation and
are predicted to fall either side of a sharp transition between planets with
and without hot stratospheres. WASP-1b is one of the most highly irradiated
planets studied to date. We measure planet/star contrast ratios in all four of
the IRAC bands for both planets (3.6-8.0um), and our results indicate the
presence of a strong temperature inversion in the atmosphere of WASP-1b,
particularly apparent at 8um, and no inversion in WASP-2b. In both cases the
measured eclipse depths favor models in which incident energy is not
redistributed efficiently from the day side to the night side of the planet. We
fit the Spitzer light curves simultaneously with the best available radial
velocity curves and transit photometry in order to provide updated measurements
of system parameters. We do not find significant eccentricity in the orbit of
either planet, suggesting that the inflated radius of WASP-1b is unlikely to be
the result of tidal heating. Finally, by plotting ratios of secondary eclipse
depths at 8um and 4.5um against irradiation for all available planets, we find
evidence for a sharp transition in the emission spectra of hot Jupiters at an
irradiation level of 2 x 10^9 erg/s/cm^2. We suggest this transition may be due
to the presence of TiO in the upper atmospheres of the most strongly irradiated
hot Jupiters
Low-Dose Volume-Perfusion CT of the Brain: Effects of Radiation Dose Reduction on Performance of Perfusion CT Algorithms
WASP-167b/KELT-13b: joint discovery of a hot Jupiter transiting a rapidly-rotating F1V star
We report the joint WASP/KELT discovery of WASP-167b/KELT-13b, a transiting
hot Jupiter with a 2.02-d orbit around a V = 10.5, F1V star with [Fe/H] = 0.1
± 0.1. The 1.5 RJup planet was confirmed by Doppler tomography of
the stellar line profiles during transit. We place a limit of < 8 MJup on its mass. The planet is in a retrograde orbit with a sky-projected
spin-orbit angle of λ = −165° ± 5° This is in
agreement with the known tendency for orbits around hotter stars to be more
likely to be misaligned. WASP-167/KELT-13 is one of the few systems where the
stellar rotation period is less than the planetary orbital period. We find
evidence of non-radial stellar pulsations in the host star, making it a
δ-Scuti or γ-Dor variable. The similarity to WASP-33, a
previously known hot-Jupiter host with pulsations, adds to the suggestion that
close-in planets might be able to excite stellar pulsations