| Minorplanet: | yes |
| Background: |
|
| 691 Lehigh | |
| Mpc Name: | (691) Lehigh |
| Alt Names: | 1909 JG |
| Pronounced: | [1] |
| Discovered: | 11 December 1909 |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Eccentricity: | 0.12194 |
| Semimajor: | 3.0115AU |
| Perihelion: | 2.6443AU |
| Aphelion: | 3.3787abbr=onNaNabbr=on |
| Period: | 5.23 yr (1908.9 d) |
| Inclination: | 13.010° |
| Asc Node: | 87.997° |
| Arg Peri: | 304.466° |
| Mean Motion: | / day |
| Orbit Ref: | [2] |
| Observation Arc: | 101.40 yr (37038 d) |
| Uncertainty: | 0 |
| Abs Magnitude: | 9.2 |
| Rotation: | 12.891abbr=onNaNabbr=on |
| Mean Radius: | km |
691 Lehigh is an asteroid orbiting the Sun in the asteroid belt, discovered in 1909.[3] It is named after Lehigh University, where its orbit was calculated in the Masters Thesis of Joseph B. Reynolds, following the observations of amateur astronomer Joel Metcalf. The asteroid is a CD:-type asteroid, suggesting its surface is largely carbonaceous, with many primitive molecules similar to those of comets. Due to this, it has a cometlike surface albedo of just 0.05, similar to fresh asphalt, meaning that it reflects only 5% of light that hits it. Lehigh is not known to be a member of any collisional asteroid family.