| Minorplanet: | yes |
| 2578 Saint-Exupéry | |
| Background: |
|
| Discovery Ref: |   |
| Discovered: | 2 November 1975 |
| Mpc Name: | (2578) Saint-Exupéry |
| Alt Names: | |
| Named After: | Antoine de Saint-Exupéry |
| Mp Category: | main-belt Eos  |
| Orbit Ref: |   |
| Epoch: | 4 September 2017 (JD 2458000.5) |
| Uncertainty: | 0 |
| Observation Arc: | 64.61 yr (23,599 days) |
| Perihelion: | 2.7101 AU |
| Semimajor: | 3.0018 AU |
| Eccentricity: | 0.0972 |
| Period: | 5.20 yr (1,900 days) |
| Mean Motion: | / day |
| Inclination: | 10.571° |
| Asc Node: | 55.704° |
| Arg Peri: | 336.25° |
| Dimensions: | km |
| Abs Magnitude: | 11.5 |
2578 Saint-Exupéry, provisional designation, is an Eoan asteroid from the outer region of the asteroid belt, approximately 17 kilometers in diameter. It was discovered by Russian astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnyj on 2 November 1975, and named after French aviator and writer Antoine de Saint-Exupéry.
Saint-Exupéry is a member the Eos family, the largest asteroid family of the outer main belt consisting of nearly 10,000 known members. The asteroid orbits the Sun at a distance of 2.7–3.3 AU once every 5 years and 2 months (1,900 days). Its orbit has an eccentricity of 0.10 and an inclination of 11° with respect to the ecliptic.
The asteroid's was first identified as at McDonald Observatory in Texas. One month later, it was also observed at the Palomar Observatory in May 1952. Its observation arc begins by 23 years prior to its official discovery observation at Nauchnyj.
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Saint-Exupéry measures 17.0 kilometers in diameter and its surface has an albedo of 0.168. Based on its absolute magnitude of 11.5, its generic diameter is between 13 and 30 kilometers, assuming an albedo in the range of 0.05 to 0.25.
As of 2017, Saint-Exupérys effective composition, rotation period and shape remain unknown.
The minor planet was named in honour of French aviator and writer Antoine de Saint-Exupéry (1900–1944). The name also alludes to Saint-Exupéry's best-known character, The Little Prince, who lives on an asteroid.
In the book, the prince's asteroid also has a unique code: B612 (which does not match this minor planet's provisional designation). However, there is another asteroid called 46610 Bésixdouze, which is French for "B-six-twelve" (B612 in hexadecimal notation equals 46610).
The official naming citation was published by the Minor Planet Center on 11 July 1987 .