Projected spin–orbit alignments from<i>Kepler</i>asteroseismology and<i>Gaia</i>astrometry

The angle between the rotation and orbital axes of stars in binary systems -- obliquity is an important indicator how these form evolve but few such measurements exist. We combine sample astrometric inclinations from Gaia DR3 with a solar-like oscillators which rotational have been measured using asteroseismology. supplement our one whose visual orbit has determined speckle interferometry present projected spin-orbit alignments five systems. find that each system, overall sample, consistent alignment there are caveats. First, asteroseismic fundamentally ambiguous and, second, we can only measure (rather than true) obliquity. If independent isotropically-distributed, however, likelihood drawing data by chance less per cent. Though small, set argues against uniformly random obliquities speculate dozens more could be made NASA's TESS mission, mostly red giants. ESA's PLATO mission will likely produce hundreds main-sequence subgiant stars.