文章基本信息

标题：The Young Planet DS Tuc Ab Has a Low Obliquity*
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作者：Benjamin T.Montet ; Adina D.Feinstein ; Rodrigo Luger 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2020
卷号：159
期号：3
页码：1523-1534
DOI：10.3847/1538-3881/ab6d6d
语种：English
出版社：American Institute of Physics
摘要：The abundance of short-period planetary systems with high orbital obliquities relative to the spin of their host stars is often taken as evidence that scattering processes play important roles in the formation and evolution of these systems.More recent studies have suggested that wide binary companions can tilt protoplanetary disks, inducing a high stellar obliquity that form through smooth processes like disk migration.DS Tuc Ab, a transiting planet with an 8.138 day period in the 40 Myr Tucana–Horologium association, likely orbits in the same plane as its now-dissipated protoplanetary disk, enabling us to test these theories of disk physics.Here, we report on Rossiter–McLaughlin observations of one transit of DS Tuc Ab with the Planet Finder Spectrograph on the Magellan Clay Telescope at Las Campanas Observatory.We confirm the previously detected planet by modeling the planet transit and stellar activity signals simultaneously.We test multiple models to describe the stellar activity-induced radial velocity variations over the night of the transit, finding the obliquity to be low: λ = 12° ± 13°, which suggests that this planet likely formed through smooth disk processes and its protoplanetary disk was not significantly torqued by DS Tuc B.The specific stellar activity model chosen affects the results at the ≈5° level.This is the youngest planet to be observed using this technique; we provide a discussion on best practices to accurately measure the observed signal of similar young planets.
关键词：Exoplanets;Exoplanet dynamics;High resolution spectroscopy;Starspots