| Minorplanet: | yes |
| Background: |
|
| Pronounced: | [1] |
| 23 Thalia | |
| Discovered: | 15 December 1852 |
| Mpc Name: | (23) Thalia |
| Alt Names: | 1938 CL; |
| Epoch: | 14 June 2006 (JD 2453900.5) |
| Semimajor: | 393.073 Gm (2.628 AU) |
| Perihelion: | 301.483 Gm (2.015 AU) |
| Aphelion: | 484.663 Gm (3.240 AU) |
| Eccentricity: | 0.233 |
| Period: | 1555.679 d (4.26 a) |
| Inclination: | 10.145° |
| Asc Node: | 67.228° |
| Arg Peri: | 59.311° |
| Mean Anomaly: | 328.687° |
| Dimensions: | 107.53 ± 2.2 km (IRAS) 106.81 ± 3.23 km |
| Density: | 3.07 ± 0.31 g/cm3 |
| Rotation: | 12.312 h |
| Spectral Type: | S  |
| Magnitude: | 9.11 to 13.19 |
| Abs Magnitude: | 7.17 |
| Albedo: | 0.2536 (geometric)[2] |
23 Thalia is a large main-belt asteroid. It was discovered by J. R. Hind on 15 December 1852, at the private observatory of W. Bishop, located in Hyde Park, London, England.[3] Bishop named it after Thalia, the Muse of comedy and pastoral poetry in Greek mythology.[4]
It is categorized as an S-type asteroid consisting of mainly of iron- and magnesium-silicates. This the second most common type of asteroid in the main belt. Based on analysis of the light curve, the object has a sidereal rotation period of . An ellipsoidal model of the light curve gives an a/b ratio of .[5]
With a semimajor axis of 2.628, the asteroid is orbiting between the 3:1 and 5:2 Kirkwood gaps in the main belt.[6] Its orbital eccentricity is larger than the median value of 0.07 for the main belt, and the inclination is larger than the median of below 4°. But most of the main-belt asteroids have an eccentricity of no more than 0.4 and an inclination of up to 30°, so the orbit of 23 Thalia is not unusual for a main-belt asteroid.[7]
Thalia has been studied by radar.[8]