| Minorplanet: | yes |
| 400 Ducrosa | |
| Background: |
|
| Discovered: | 15 March 1895 |
| Named After: | J. Ducros |
| Mpc Name: | (400) Ducrosa |
| Alt Names: | 1895 BU |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 3.1259AU |
| Perihelion: | 2.76117AU |
| Aphelion: | 3.49063abbr=onNaNabbr=on |
| Eccentricity: | 0.11668 |
| Inclination: | 10.5354° |
| Asc Node: | 327.145° |
| Arg Peri: | 238.468° |
| Mean Anomaly: | 294.184° |
| Avg Speed: | 16.84 km/s |
| Rotation: | 6.87abbr=onNaNabbr=on 6.87 ± 0.01 hours |
| Abs Magnitude: | 10.5 |
| Mean Motion: | / day |
| Observation Arc: | 121.08 yr (44225 d) |
| Uncertainty: | 0 |
| Moid: | 1.7762AU |
| Jupiter Moid: | 1.59886AU |
| Tisserand: | 3.178 |
400 Ducrosa is a typical Main belt asteroid. It was discovered by Auguste Charlois on 15 March 1895 in Nice, and named for It J. Ducros, a mechanic at the Nice Observatory. This minor planet is orbiting the Sun at a distance of with a period of and an orbital eccentricity of 0.117. The orbital plane is inclined at an angle of 10.5° to the plane of the ecliptic.
This asteroid has a B-type taxonomy, indicating it has a relatively bright geometric albedo for a carbonaceous asteroid. It has an estimated diameter of . Photometric measurements of the asteroid made in 2005 at the Palmer Divide Observatory showed a light curve with a rotation period of and a brightness variation of 0.62 in magnitude. A 2020 study found a rotation period of with a variation of 0.57 magnitude.