(219774) 2001 YY145, provisional designation 2001 YY145 is a stony background asteroid and exceptionally slow rotator from the central region of the asteroid belt, approximately 1.5 kilometers (0.9 miles) in diameter.
It was discovered on 18 December 2001, by astronomers with the Lowell Observatory Near-Earth-Object Search at Anderson Mesa Station near Flagstaff, Arizona, in the United States.
[5] In October 2013, a rotational lightcurve was obtained of this asteroid from photometric observations in the R-band by astronomers at the Palomar Transient Factory in California.
According to the Light Curve Data Base, it is the 13th slowest rotating minor planet known to exist among more than 15,000 observed small Solar System bodies.
Due to its high brightness variation of 0.86 magnitude, the body is likely to have a non-spheroidal shape (U=2).