61 Danaë
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| Discovery | |
|---|---|
| Discovered by | H. Goldschmidt |
| Discovery date | September 9, 1860 |
| Designations | |
| Named after | Danaë |
| Alternative names | A917 SM; 1953 RL1 |
| Minor planet category | Main belt |
| Orbital characteristics | |
| Epoch June 14, 2006 (JD 2453900.5) | |
| Aphelion | 520.969 Gm (3.482 AU) |
| Perihelion | 371.280 Gm (2.482 AU) |
| Semi-major axis | 446.125 Gm (2.982 AU) |
| Eccentricity | 0.168 |
| Orbital period | 1881.025 d (5.15 a) |
| Average orbital speed | 17.13 km/s |
| Mean anomaly | 91.103° |
| Inclination | 18.218° |
| Longitude of ascending node | 333.774° |
| Argument of perihelion | 13.831° |
| Physical characteristics | |
| Dimensions | 82.52 ± 2.73[1] km |
| Mass | (2.89 ± 2.78) × 1018[1] kg |
| Mean density | 9.81 ± 9.49[1] g/cm3 |
| Equatorial surface gravity | 0.0126 m/s² |
| Escape velocity | 0.0322 km/s |
| Rotation period | 0.4771 d (11.45 h) |
| Albedo | 0.2224±0.025 |
| Temperature | ~155 K |
| Spectral type | S |
| Absolute magnitude (H) | 7.68 |
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61 Danaë (/ˈdænəjiː/ DAN-ə-yee or /dəˈneɪ.ə/ də-NAY-ə) is a moderately large, rocky main belt asteroid. It was discovered by Hermann Goldschmidt on September 9, 1860 from his balcony in Paris.
Goldschmidt was ill when asked to name the asteroid, and requested his fellow asteroid-hunter Robert Luther to name it instead. Luther chose to name it after Danaë, the mother of Perseus in Greek mythology.[2] Danaë was the first asteroid to have a diacritical character in its official name.
In 1985, a study of lightcurve data suggested that Danaë may have a moon. If so, the main body would be an ellipsoid measuring 85×80×75 km, and the moon would orbit 101 km away, measuring 55×30×30 km. The density of both would be 1.1 g/cm³.
References
- ↑ 1.0 1.1 1.2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
- ↑ Schmadel, Lutz (2003). Dictionary of minor planet names (fifth ed.). Germany: Springer. p. 21. ISBN 3-540-00238-3. Retrieved 2008-12-29.
- A. Cellino, R. Pannunzio, V. Zappalà, P. Farinella, and P. Paolicchi, 1985, Do we observe light curves of binary asteroids?, Astronomy and Astrophysics, Vol. 144, No. 2, pp. 355–362.
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