| Minorplanet: | yes |
| Background: |
|
| 354 Eleonora | |
| Discoverer: | Auguste Charlois |
| Discovered: | 17 January 1893 |
| Mpc Name: | (354) Eleonora |
| Adjective: | Eleonorian |
| Alt Names: | 1893 A |
| Mp Category: | Main belt |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 2.79777AU |
| Perihelion: | 2.47676AU |
| Aphelion: | 3.1188abbr=onNaNabbr=on |
| Eccentricity: | 0.11474 |
| Period: | 4.68 yr (1709.3 d) |
| Inclination: | 18.403° |
| Asc Node: | 140.37° |
| Arg Peri: | 5.5215° |
| Mean Anomaly: | 123.762° |
| Dimensions: | c/a = |
| Mean Diameter: | [1] |
| Mass: | |
| Density: | 3.602 ± 0.754/0.701 g/cm |
| Rotation: | 4.277abbr=onNaNabbr=on |
| Spectral Type: | S |
| Abs Magnitude: | 6.15 |
| Albedo: | 0.172 |
| Mean Motion: | / day |
| Observation Arc: | 123.16 yr (44983 d) |
| Uncertainty: | 0 |
354 Eleonora is a large, stony main-belt asteroid that was discovered by the French astronomer Auguste Charlois on January 17, 1893, in Nice.
Photometric observations of this asteroid gave a light curve with a period of 13.623 hours. The data was used to construct a model for the asteroid, revealing it to be a regular-shaped object, spinning about a pole with ecliptic coordinates (β, λ) = (+20°, 356°), although this is with an accuracy of only ±10°. The ratio of the major to minor axes lengths is roughly equal to 1.2. It is classified as an S-type asteroid and has an estimated size of 154.34 km. The spectrum of 354 Eleonora reveals the strong presence of the mineral olivine, a relative rarity in the asteroid belt.
During favorable oppositions, such as in 1968 and 2010, Eleonora can reach an apparent magnitude of +9.31.