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Post Info TOPIC: XO-3 Exoplanetary System
Blobrana


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XO-3
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Title: Further Observation of the Tilted Planet XO-3: A New Determination of Spin-orbit Misalignment, a Possible Third Body, and Limits on Differential Rotation
Authors: Teruyuki Hirano, Norio Narita, Bun'ei Sato, Joshua N. Winn, Wako Aoki, Motohide Tamura, Atsushi Taruya, Yasushi Suto

We report on observations of the Rossiter-McLaughlin (RM) effect for the XO-3 exoplanetary system. The RM effect for the system was previously measured by two different groups, but their results were statistically inconsistent. To obtain a decisive result we observed two full transits of XO-3b with the Subaru 8.2-m telescope. By modelling these data with a new and more accurate analytic formula for the RM effect, we find the projected spin-orbit angle to be \lambda=37.3 deg ± 3.0 deg, in good agreement with the previous finding by Winn et al. 2009. In addition, an offset of ~22 m/s was observed between the two transit datasets. This offset could be a signal of a third body in the XO-3 system, a possibility that should be checked with future observations. We also attempt to search for a possible signature of the stellar differential rotation in the RM data for the first time, and put weak upper limits on the differential rotation parameters.

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Blobrana


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RE: Exoplanet XO-3b
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Blobrana


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Live webcast of XO-3 b Extrasolar Planet Transit

18:00 UTC, 13th February, 2010

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Blobrana


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On the evening of February 13th, the exoplanet XO-3b will transit its parent star, and if you have access to a (large) amateur telescope, you can observe this event too!
The National Institute for Astrophysics, Astronomical Observatories
of Brera and Palermo Italy plan to collect light curve data acquired on Feb 13 by as many observers as possible, and to perform an accurate analysis of them.
Source


BRERA_Terre del cielo




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Blobrana


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XO-3b
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An exoplanet with a steeply titled orbit around the plane of a distant star's equator has been discovered by an international team of astronomers, and it is being hailed as a finding that contradicts theories about how planetary systems form.
Observations conducted of planet XO-3b at the W. M. Keck Observatory on the Big Island of Hawaii's Mauna Kea have determined the angle of the orbit to be about 37 degrees from the stars equator. The so called "misalignment" of the planet's orbit contradicts simple theories of planet formation, according to astronomer Geoff Marcy of University of California Berkeley, who coauthored the discovery paper.

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Blobrana


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Planet found in tilted orbit around distant star
An international team of researchers has found a planet around another star whose orbit is steeply tilted from the plane of the star's equator, a finding that contradicts some theories about how solar systems form.
In our own solar system, all of the planets orbit the sun almost exactly in the same plane as the sun's rotation - and that alignment is required by currently accepted theories of how stars and planets form from a collapsing disk of dust and gas. Any misalignment, such as the one the team found, must have occurred as a result of a disturbance sometime after the planet's formation, theorists say.
Astronomers are interested in exploring the characteristics of such distant planets partly to help refine theories of planet formation, and partly just to understand the kinds of variations that may be possible in the universe around us.

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XO-3 Exoplanetary System
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Title: The Spin-Orbit Misalignment of the XO-3 Exoplanetary System
Authors: Joshua N. Winn, John Asher Johnson, Daniel Fabrycky, Andrew W. Howard, Geoffrey W. Marcy, Norio Narita, Ian J. Crossfield, Yasushi Suto, Edwin L. Turner, Gil Esquerdo, Matthew J. Holman

We present photometric and spectroscopic observations of the 2009 Feb. 2 transit of the exoplanet XO-3b. The new data show conclusively that the planetary orbital axis and stellar rotation axis are misaligned. We thereby confirm the previous finding by Hebrard and coworkers, although we find a significantly smaller angle (37.3 ±3.7 deg) between the sky projections of the two axes. XO-3b is the first exoplanet known to have a highly inclined orbit relative to the equatorial plane of its parent star, and as such it may fulfil the predictions of some scenarios for the migration of massive planets into close-in orbits. We revisit the statistical analysis of spin-orbit alignment in hot-Jupiter systems. Assuming the stellar obliquities to be drawn from a Rayleigh distribution, we find the mode of the distribution to be 13^{+5}_{-2} deg. It remains the case that a model representing two different migration channels--in which some planets are drawn from a perfectly-aligned distribution and the rest are drawn from an isotropic distribution--is favoured over a single Rayleigh distribution, but with reduced significance.

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