Over the past 25 years, we’ve found thousands of worlds beyond our solar system. Nonetheless, some categories of exoplanets remain elusive — for instance, planets that orbit their hosts on long, slow paths. A new study shows how we might hunt these worlds down.
Artist’s impression of a hot Jupiter transiting across the face of its host star. [ESA/C. Carreau]Since the first exoplanet discovery a quarter century ago, we’ve found more than 4,000 confirmed planets orbiting other stars. A large number of these discoveries are planets that transit across the face of their host star — most identified by the Kepler Space Telescope or, more recently, by the Transiting Exoplanet Survey Satellite (TESS). These exoplanets are valuable targets because we can use the transits to measure properties like their radii, densities, bulk compositions, and even their atmospheres.
Unfortunately, due to the nature of transit detections, our observations are inherently biased: it’s easier to detect and confirm short-period, large planets, which means we know a lot about hot Jupiters, but relatively little about wide-orbit, cooler planets.
Because the TESS spacecraft observes a typical region for less than a month, planets on wide orbits longer than 30 days will register ...