2423 Ibarruri, provisional designation 1972 NC, is an eccentric, tumbling and rare-type asteroid, classified as slow rotator and sizable Mars-crosser from the inner regions of the asteroid belt, approximately 5 kilometers in diameter.
Ibarruri orbits the Sun in the inner main-belt at a distance of 1.6–2.8 AU once every 3 years and 3 months (1,183 days). Its orbit has an eccentricity of 0.28 and an inclination of 4° with respect to the ecliptic.
The spectral type of the asteroid is that of a rare A-type in the SMASS taxonomy, with its surface consisting of almost pure olivine, which gives the body a very reddish color. As of November 2015, only 17 minor planets of this type are known.
As a spectroscopic A-type asteroid, it belongs to the larger group of bodies with a silicaceous composition. However, the Collaborative Asteroid Lightcurve Link classifies the asteroid into the carbonaceous group, despite the fact that is assumes a relatively high geometric albedo of 0.20, which is rather typical for stony asteroids.
Slow rotator and tumbler
Ibarruri has a notably slow rotation period of 140 hours,[a] and seems to be in a non-principal axis rotation (NPAR), colloquially called as "tumbling".