Euthanasia in the Netherlands

Irwin, Michael

doi:10.1177/014107689909200926

Cited by 1 publication

(3 citation statements)

References 1 publication

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Section: Discussionmentioning

confidence: 97%

“…Previous studies have suggested that HD 17156b may be enriched in heavy elements (Irwin et al 2008;Winn et al 2009). The models of Fortney et al (2007) for a solarcomposition planet of the mass of HD 17156b predict a 1.10 R J radius, which is discrepant with the Irwin et al (2008) and Winn et al (2009) determinations at roughly 1σ. Our larger planet radius measurement of 1.095 ± 0.020 R J (1.0845 ± 00.70R J ) may lessen the need for substantial heavy-element enrichment, but as Winn et al (2009) points out, the Fortney et al (2007) models do not take into account tidal heating due to nonzero eccentricity, and the models are calculated for 4.5 Gyr, while the age of the system is estimated to be only 3 Gyr.…”

Section: Discussionmentioning

confidence: 97%

“…Perhaps surprisingly, Rossiter-McLaughlin studies of Cochran et al (2008), Barbieri et al (2009), and Narita et al (2009) have found projected spin-orbit angles consistent with zero misalignment for the HD 17156 system. Previous photometric studies of HD 17156b (Irwin et al 2008, Gillon et al 2008, Barbieri et al 2009) have determined the planetary radius to be below the theoretical expectation for a solar composition ball of the same mass and equilibrium temperature (R p = 1.1 R J ), which suggests that the planet may be significantly enriched in heavy-elements. We note however that the discrepancy with R p = 1.1 R J in each study is 1σ or less.…”

Section: Introductionmentioning

confidence: 90%

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PRECISE ESTIMATES OF THE PHYSICAL PARAMETERS FOR THE EXOPLANET SYSTEM HD 17156 ENABLED BYHUBBLE SPACE TELESCOPEFINE GUIDANCE SENSOR TRANSIT AND ASTEROSEISMIC OBSERVATIONS

Nutzman¹,

Gilliland²,

McCullough³

et al. 2010

ApJ

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We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors (FGS) on board the Hubble Space Telescope (HST ) 5 . We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio R p /R ⋆ = 0.07454 ± 0.00035, inclination i = 86.49 +0.24 −0.20 deg, and scaled semi-major axis a/R ⋆ = 23.19 +0.32 −0.27 . This last value translates directly to a mean stellar density determination ρ ⋆ = 0.522 +0.021 −0.018 g cm −3 . Analysis of asteroseismology observations by the companion paper of Gilliland et al. (2009) provides a consistent but significantly refined measurement 6 of ρ ⋆ = 0.5308 ± 0.0040 g cm −3 . We compare stellar isochrones to this density estimate and find M ⋆ = 1.275 ± 0.018 M ⊙ and a stellar age of 3.37 +0.20 −0.47 Gyr. Using this estimate of M ⋆ and incorporating the density constraint from asteroseismology, we model both the photometry and published radial velocities to estimate the planet radius R p = 1.0870 ± 0.0066 R J and the stellar radius R ⋆ = 1.5007 ± 0.0076 R ⊙ . The planet radius is larger than While this work was in press, the companion work revised this measurement to ρ ⋆ = 0.5301 ± 0.0044 g cm −3 . We note that the change, which is less than 0.2 of the error, would translate to a stellar radius change of less than 0.001 R ⊙ and does not materially affect the results presented in this paper.that found in previous studies and consistent with theoretical models of a solarcomposition gas giant of the same mass and equilibrium temperature. For the three transits, we determine the times of mid-transit to a precision of 6.2 s, 7.6 s, and 6.9 s, and the transit times for HD 17156 do not show any significant departures from a constant period. The joint analysis of transit photometry and asteroseismology presages similar studies that will be enabled by the NASA Kepler Mission.

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