It was discovered by Japanese astronomers Yoshikane Mizuno and Toshimasa Furuta at Kani Observatory (403) on 21 November 1989.
[1] It was first identified as 1974 TB at the Chilean Cerro El Roble Station in 1974, extending the body's observation arc by 15 years prior to its discovery.
[4] A rotational lightcurve of Makio was obtained from photometric observations made by Julian Oey at the Australian Kingsgrove Observatory (E19) in March 2009.
Lightcurve analysis gave a rotation period of 7.830 hours with a small brightness variation of 0.08 magnitude, indicative of a spheroidal shape (U=2).
[7] According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Makio measures 7.0 kilometers in diameter and its surface has an albedo of 0.33,[5][6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 9.4 kilometers with an absolute magnitude of 12.5.