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Post Info TOPIC: iota Draconis
Blobrana


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RE: iota Draconis
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Title: Fundamental Parameters of the Exoplanet Host K Giant Star iota Draconis from the CHARA Array
Authors: Ellyn K. Baines, Harold A. McAlister, Theo A. ten Brummelaar, Nils H. Turner, Judit Sturmann, Laszlo Sturmann, P. J. Goldfinger, Christopher D. Farrington, Stephen T. Ridgway

We measured the angular diameter of the exoplanet host star iota Dra with Georgia State University's Centre for High Angular Resolution Astronomy (CHARA) Array interferometer, and, using the star's parallax and photometry from the literature, calculated its physical radius and effective temperature. We then combined our results with stellar oscillation frequencies from Zechmeister et al. (2008) and orbital elements from Kane et al. (2010) to determine the masses for the star and exoplanet. Our value for the central star's mass is 1.82 ±0.23 Solar masses, which means the exoplanet's minimum mass is 12.6 ±1.1 Jupiter masses. Using our new effective temperature, we recalculated the habitable zone for the system, though it is well outside the star-planet separation.

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Blobrana


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Iota Draconis b
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Iota Draconis b was discovered in 2002 during a radial velocity study of K-class giant stars and was the first planet discovered orbiting a giant star. It is in an eccentric orbit, which aided its detection as giant stars have pulsations which can mimic the presence of a planet.
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Blobrana


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Posts: 131433
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RE: iota Draconis
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Title: On the Transit Potential of the Planet Orbiting iota Draconis
Authors: Stephen R. Kane, Sabine Reffert, Gregory W. Henry, Debra Fischer, Christian Schwab, Kelsey I. Clubb, Christoph Bergmann
(Version v2)

Most of the known transiting exoplanets are in short-period orbits, largely due to the bias inherent in detecting planets through the transit technique. However, the eccentricity distribution of the known radial velocity planets results in many of those planets having a non-negligible transit probability. One such case is the massive planet orbiting the giant star iota Draconis, a situation where both the orientation of the planet's eccentric orbit and the size of the host star inflate the transit probability to a much higher value than for a typical hot Jupiter. Here we present a revised fit of the radial velocity data with new measurements and a photometric analysis of the stellar variability. We provide a revised transit probability, an improved transit ephemeris, and discuss the prospects for observing a transit of this planet from both the ground and space.

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Blobrana


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Title: The Discovery of Stellar Oscillations in the K Giant iota Dra
Authors: Mathias Zechmeister (1 and 2), Sabine Reffert (3), Artie P. Hatzes (2), Michael Endl (4), Andreas Quirrenbach (3) ((1) MPIA, Heidelberg, Germany, (2) TLS, Tautenburg, Germany, (3) LSW, Heidelberg, Germany, (4) University of Texas, Austin, USA)

iota Dra (HIP 75458) is a well-known example for a K giant hosting a substellar companion since its discovery by Frink et al. (2002). We present radial velocity measurements of this star from observations taken with three different instruments spanning nearly 8 years. They show more clearly that the RV period is long-lived and coherent thus supporting the companion hypothesis. The longer time baseline now allows for a more accurate determination of the orbit with a revised period of P=511 d and an additional small linear trend, indicative of another companion in a wide orbit. Moreover we show that the star exhibits low amplitude, solar like oscillations with frequencies around 3-4 d^{-1} (34.7-46.3 mu Hz).

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