What is the largest object on which the Yarkovsky effect has been observed? The Yarkovsky effect is responsible for changes in the rotation and orbit of some celestial bodies, most notably asteroids. It has been measured on asteroids, such as 6489 Golevka and 1999 RQ36.

What is the largest object on which the Yarkovsky effect has been observed? Scholarpedia has an excellent article and list of asteroids, but the list isn't necessarily complete, and I don't know if the effect has been detected on other (non-asteroid) bodies.
According to Vokrouhlicky et al. 2015 Yarkovsky forces can be measured for small bodies with diameters up to 30-40 km. The largest object they have in their list of Yarkovsky detections is 4179 Toutatis with a diameter of (only) 2.8 km. I am not aware if Yarkovsky forces have been measured on anything larger than asteroids.