[10] In the Tholen taxonomy, Innes has an AS-spectral type, an intermediate form of the rare A-types to the common stony asteroids (also see category listing).
[12] In May 2005, astronomers Robert Stephens at the Center for Solar System Studies, California, and Lorenzo Franco at Balzaretto Observatory, near Rome, each obtained a rotational lightcurve of Innes.
The photometric observations gave an identical rotation period of 3.191±0.001 hours with a brightness variation of 0.22 and 0.25 magnitude, respectively (U=3/3).
[7][8] According to the 2014-revised survey result of NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Innes measures 13.35 kilometers in diameter and its surface has an albedo of 0.248,[3] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 14.76 kilometers with an absolute magnitude of 11.52.
He was a skilled observational astronomer, famous for his deliberate search for and discovery of the nearest star, Proxima Centauri, in 1915.