In 2005, two rotational lightcurves of Gibbs were obtained from photometric observations by Italian amateur astronomers Federico Manzini and Roberto Crippa. Lightcurve analysis gave a rotation period of 3.06 and 3.06153 hours with a brightness variation of 0.31 and 0.39 magnitude, respectively (U=2/3-). In December 2016, Robert Stephens obtained a well-defined lightcurve at his Trojan Station (U81) that gave a period of 3.189 hours and an amplitude of 0.26 magnitude (U=3).[a]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Gibbs measures between 5.04 and 5.99 kilometers in diameter and its surface has an albedo between 0.283 and 0.30, while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.23 – derived from 25 Phocaea, the Phocaea family's largest member and namesake – and calculates a diameter of 6.35 kilometers based on an absolute magnitude of 13.2.
^ abLightcurve plot for (2937) Gibbs. Robert D. Stephens (2016). Rotation period of 3.189±0.003 hours with a brightness amplitude of 0.26 mag. Quality Code of 3. Summary figures at the CS3 website and at the LCDB