| Minorplanet: | yes |
| Mpc Name: | (174) Phaedra |
| Background: |
|
| 174 Phaedra | |
| Alt Names: | A877 RA |
| Pronounced: | [1] |
| Discovered: | 2 September 1877 |
| Semimajor: | 2.8615AU |
| Perihelion: | 2.4572AU |
| Aphelion: | 3.2658abbr=onNaNabbr=on |
| Period: | 4.84 yr (1768.0 d) |
| Inclination: | 12.124° |
| Eccentricity: | 0.14128 |
| Rotation: | 5.744abbr=onNaNabbr=on |
| Abs Magnitude: | 8.48 |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Asc Node: | 327.69° |
| Arg Peri: | 289.08° |
| Mean Motion: | / day |
| Observation Arc: | 138.61 yr (50629 d) |
| Uncertainty: | 0 |
| Moid: | 1.47439AU |
| Jupiter Moid: | 1.99981AU |
| Tisserand: | 3.254 |
174 Phaedra is a sizable, rocky main belt asteroid that was discovered by Canadian-American astronomer James Craig Watson on September 2, 1877, and named after Phaedra, the tragic lovelorn queen in Greek mythology.
The asteroid is orbiting the Sun with a period of 4.84 years and an eccentricity of 0.14. Lightcurve data obtained from Phaedra indicates a rather irregular or elongated body. It has a cross-section size of ~35 km. Photometric observations of this asteroid at the Shadowbox Observatory in Carmel, Indiana, during 2009 gave a light curve with a period of 4.96 ± 0.01 hours. This is consistent with previous studies in 1977, 1988, and 2008. The asteroid's pole of rotation lies just 5–16° away from the plane of the ecliptic.