(9942) 1989 TM1, provisional designation 1989 TM1, is a background asteroid from the central region of the asteroid belt, approximately 4.5 kilometers (2.8 miles) in diameter. It was discovered on 8 October 1989, by Japanese astronomers Nobuhiro Kawasato and Tsutomu Hioki at the Okutama Observatory (877) in Japan. The asteroid has a tentative rotation period of 3.1 hours.