We present here the discovery of a new class of superslow rotating asteroids (Prot ≳1000 h) in data extracted from the Asteroid Terrestrial-impact Last Alert System (ATLAS) and Zwicky Transient Facility (ZTF) all-sky surveys. Of the 39 rotation periods we report here, 32 have periods longer than any previously reported unambiguous rotation periods currently in the Asteroid Light Curve Data base. In our sample, seven objects have a rotation period >4000 h and the longest period we report here is 4812 h (∼200 d). We do not observe any correlation between taxonomy, albedo, or orbital properties with superslow rotating status. The most plausible mechanism for the creation of these very slow rotators is if their rotations were slowed by YORP spin-down. Superslow rotating asteroids may be common, with at least 0.4 per cent of the main-belt asteroid population with a size range between 2 and 20 km in diameter rotating with periods longer than 1000 h.

中文翻译：

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用 ATLAS 和 ZTF 光度法发现超慢速旋转小行星

我们在这里展示了从小行星陆地撞击最后警报系统 (ATLAS) 和 Zwicky 瞬态设施 (ZTF) 全天调查中提取的数据中发现的一类新的超慢速旋转小行星 (Prot ≳1000 h)。在我们在这里报告的 39 个自转周期中，有 32 个周期比目前小行星光曲线数据库中任何先前报告的明确自转周期都要长。在我们的样本中，七个物体的旋转周期 > 4000 小时，我们在这里报告的最长周期是 4812 小时（~200 天）。我们没有观察到分类学、反照率或具有超慢旋转状态的轨道特性之间的任何相关性。创建这些非常慢的旋转器的最合理的机制是它们的旋转是否因 YORP 旋转而减慢。超慢速旋转小行星可能很常见，至少有 0 个。