Publication Date:
2013-10-29
Description:
Recent results suggest that the two planets in the HD 82943 system are inclined to the sky plane by 20 ± 4°. Here, we show that the debris disc in this system is inclined by 27 ± 4°, thus adding strength to the derived planet inclinations and suggesting that the planets and debris disc are consistent with being aligned at a level similar to the Solar system. Further, the stellar equator is inferred to be inclined by 28 ± 4°, suggesting that the entire star–planet–disc system is aligned, the first time such alignment has been tested for radial velocity discovered planets on ~au wide orbits. We show that the planet–disc alignment is primordial, and not the result of planetary secular perturbations to the disc inclination. In addition, we note three other systems with planets at 10 au discovered by direct imaging that already have good evidence of alignment, and suggest that empirical evidence of system-wide star–planet–disc alignment is therefore emerging, with the exception of systems that host hot Jupiters. While this alignment needs to be tested in a larger number of systems, and is perhaps unsurprising, it is a reminder that the system should be considered as a whole when considering the orientation of planetary orbits.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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