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EXOPLANETARY SPIN-ORBIT ALIGNMENT: RESULTS FROM THE ENSEMBLE OF ROSSITER-MCLAUGHLIN OBSERVATIONS
| Content Provider | Scilit |
|---|---|
| Author | Fabrycky, Daniel C. Winn, Joshua N. |
| Copyright Year | 2009 |
| Description | Journal: The Astrophysical Journal One possible diagnostic of planet formation, orbital migration, and tidal evolution is the angle ψ between a planet's orbital axis and the spin axis of its parent star. In general, ψ cannot be measured, but for transiting planets one can measure the angle λ between the sky projections of the two axes via the Rossiter-McLaughlin effect. Here, we show how to combine measurements of λ in different systems to derive statistical constraints on ψ. We apply the method to 11 published measurements of λ, using two different single-parameter distributions to describe the ensemble. First, assuming a Rayleigh distribution (or more precisely, a Fisher distribution on a sphere), we find that the peak value is less than 22° with 95% confidence. Second, assuming that a fraction f of the orbits have random orientations relative to the stars, and the remaining fraction (1 – f) are perfectly aligned, we find f < 0.36 with 95% confidence. This latter model fits the data better than the Rayleigh distribution, mainly because the XO-3 system was found to be strongly misaligned while the other 10 systems are consistent with perfect alignment. If the XO-3 result proves robust, then our results may be interpreted as evidence for two distinct modes of planet migration. |
| Related Links | http://arxiv.org/pdf/0902.0737 http://iopscience.iop.org/article/10.1088/0004-637X/696/2/1230/pdf |
| Ending Page | 1240 |
| Page Count | 11 |
| Starting Page | 1230 |
| ISSN | 0004637X |
| DOI | 10.1088/0004-637x/696/2/1230 |
| Journal | The Astrophysical Journal |
| Issue Number | 2 |
| Volume Number | 696 |
| Language | English |
| Publisher | IOP Publishing |
| Publisher Date | 2009-04-23 |
| Access Restriction | Open |
| Subject Keyword | Journal: The Astrophysical Journal Astronomy and Astrophysics |
| Content Type | Text |
| Resource Type | Article |
| Subject | Astronomy and Astrophysics Space and Planetary Science |
