New twilight telescope surveys reveal asteroids hidden by the Sun’s intense glare

Asteroid surveys generally occur at night and primarily locate objects that lie beyond Earth’s orbit. In this Perspective, Scott Sheppard highlights the new telescopic surveys that are turning their gaze inward, braving the Sun’s intense glare, to search for the near-Earth objects (NEOs) that lie within Earth’s orbit during twilight. These surveys have recently identified many previously undiscovered asteroids interior to Earth, including the first asteroid with an orbit interior to Venus (‘Ayló'chaxnim 2020 AV2) and an asteroid with the shortest-known orbital period around the Sun (2021 PH27). Generally, objects that orbit between our planet and the Sun are difficult to detect as they are often obscured by the Sun’s powerful glare. These include a range of NEOs that belong to classifications like Atiras (those with orbits interior to Earth), Vatiras (those with orbits interior of Venus), and the hypothetical Vulcanoids (those with orbits interior of Mercury), which have not yet been observed. Here, Sheppard discusses what these recent discoveries and continued telescopic surveys toward the Sun could tell us about these unique classes of asteroids, including about their formation, and he also highlights their potential to provide crucial asteroid tracking data.