Highlights - 29 January 2010 (vol. 510)
Published on 26 January 2010
|HIGHLIGHTS: this week in A&A
29 January 2010 (vol. 510)
In section 10. Planets and planetary systems
“The dynamical origin of the multi-planetary system HD45364”, by H. Rein, J. C. B. Papaloizou, and W. Kley, A&A 510, A4
HD45364 is a system containing a Saturn-mass planet at 0.7 AU and a Jupiter-mass planet at 0.9 AU from a star that is slightly less massive than our own Sun. The two planets appear to be in 3:2 resonance, which is puzzling because inward migrating embryos should first cross the 2:1 resonance and stay locked there. However, Rein et al. show with hydrodynamical simulations of planets in circumstellar disks that the outer planet may have migrated very rapidly, under so-called type-III migration, to pass through the 2:1 resonance and end up in the 3:2 resonance as observed. Moreover, the orbital elements that Rein et al. find for this system are different from those previously found by radial velocimetry alone. The authors make predictions that can be tested in the forthcoming years. They are the first predictions of orbital elements derived from formation theories.
© Astronomy & Astrophysics 2010