173 Ino is a large asteroid and the parent body of the Ino family, located in the central regions of the asteroid belt, approximately 150 kilometers (93 miles) in diameter.

It was discovered on 1 August 1877, by French astronomer Alphonse Borrelly at Marseille Observatory in southern France, and named after the queen Ino from Greek mythology.

[1][3] The dark Xk-type asteroid has a rotation period of 6.15 hours.

[1] In the Tholen classification, Ino is a common carbonaceous C-type, while in the SMASS classification it is a Xk-subtype that transitions between the X-type and uncommon K-type asteroids.

The combined data gave an irregular, asymmetrical light curve with a period of 6.163 ± 0.005 hours and a brightness variation of 0.10–0.15 in magnitude.