4257 Ubasti, provisional designation 1987 QA, is a stony asteroid, classified as near-Earth object of the Apollo group and as Mars-crosser, approximately 1.5 kilometers in diameter.
It was discovered by American astronomer Jean Mueller at the Palomar Observatory in California on 23 August 1987.
[3] The asteroid was named for Bastet – also known as Baast, Ubaste or Ubasti – the Egyptian goddess of cats.
[5] However, the Lowell Observatory Near-Earth Asteroid Photometric Survey has measured the body's brightness variation caused by its rotation, which gave a maximum of 0.36 magnitude.
[6] According to the survey carried out by the Japanese Akari satellite, Ubasti measures 1.30 kilometers in diameter and its surface has an albedo of 0.376,[4] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.96 kilometers based on an absolute magnitude of 15.9.