dc.contributor.author | Kraus, S | |
dc.contributor.author | LeBouquin, J-B | |
dc.contributor.author | Kreplin, A | |
dc.contributor.author | Davies, CL | |
dc.contributor.author | Hone, E | |
dc.contributor.author | Monnier, JD | |
dc.contributor.author | Gardner, T | |
dc.contributor.author | Kennedy, G | |
dc.contributor.author | Hinkley, S | |
dc.date.accessioned | 2020-06-24T12:44:57Z | |
dc.date.issued | 2020-06-29 | |
dc.description.abstract | A crucial diagnostic that can tell us about processes involved in the formation and dynamical evolutionof planetary systems is the angle between the rotation axis of a star and a planet's orbital angular momentum vector ("spin-orbit" alignment or "obliquity"). Here we present the first spin-orbit alignment measurement for a wide-separation exoplanetary system, namely on the directly-imaged planet $\beta$ Pictoris b. We use VLTI/GRAVITY spectro-interferometry with an astrometric accuracy of 1 $\mu$as (microarcsecond) in the Br$\gamma$ photospheric absorption line to measure the photocenter displacement associated with the stellar rotation. Taking inclination constraints from astroseismology into account, we constrain the 3-dimensional orientation of the stellar spin axis and find that $\beta$ Pic b orbits its host star on a prograde orbit. The angular momentum vectors of the stellar photosphere, the planet, and the outer debris disk are well-aligned with mutual inclinations $<3\pm5^{\circ}$, which indicates that $\beta$ Pic b formed in a system without significant primordial misalignments. Our results demonstrate the potential of infrared interferometry to measure the spin-orbit alignment for wide-separation planetary systems, probing a highly complementary regime to the parameter space accessible with the Rossiter-McLaughlin effect. If the low obliquity is confirmed by measurements on a larger sample of wide-separation planets, it would lend support to theories that explain the obliquity in Hot Jupiter systems with dynamical scattering and the Kozai-Lidov mechanism. | en_GB |
dc.description.sponsorship | European Research Council (ERC) | en_GB |
dc.identifier.citation | Vol. 897 (1), article L8 | en_GB |
dc.identifier.doi | 10.3847/2041-8213/ab9d27 | |
dc.identifier.grantnumber | 639889 | en_GB |
dc.identifier.uri | http://hdl.handle.net/10871/121635 | |
dc.language.iso | en | en_GB |
dc.publisher | IOP Publishing / American Astronomical Society | en_GB |
dc.rights | © 2020. The American Astronomical Society. All rights reserved. | en_GB |
dc.subject | stars: rotation | en_GB |
dc.subject | stars: individual (β Pictoris) | en_GB |
dc.subject | planets and satellites: individual (β Pictoris b) | en_GB |
dc.subject | planets and satellites: dynamical evolution and stability | en_GB |
dc.subject | planetary systems | en_GB |
dc.subject | techniques: interferometric | en_GB |
dc.title | Spin-orbit alignment of the β Pictoris planetary system | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2020-06-24T12:44:57Z | |
dc.identifier.issn | 2041-8205 | |
dc.description | This is the final version. Available from IOP Publishing via the DOI in this record | en_GB |
dc.identifier.eissn | 2041-8213 | |
dc.identifier.journal | Astrophysical Journal Letters | en_GB |
dc.rights.uri | http://www.rioxx.net/licenses/all-rights-reserved | en_GB |
dcterms.dateAccepted | 2020-06-16 | |
rioxxterms.version | VoR | en_GB |
rioxxterms.type | Journal Article/Review | en_GB |
refterms.dateFCD | 2020-06-24T12:40:13Z | |
refterms.versionFCD | AM | |
refterms.dateFOA | 2020-07-16T13:32:18Z | |
refterms.panel | B | en_GB |