149 Medusa
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Discovery[1] and designation
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| Discovered by | Henri Joseph Perrotin |
| Discovery date | September 21, 1875 |
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Designations
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| Alternative names[1] | |
| Minor planet category |
Main belt |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 346.542 Gm (2.316 AU) |
| Perihelion | 304.026 Gm (2.032 AU) |
| Semi-major axis | 325.284 Gm (2.174 AU) |
| Eccentricity | 0.065 |
| Orbital period | 1171.128 d (3.21 a) |
| Average orbital speed | 20.18 km/s |
| Mean anomaly | 284.523° |
| Inclination | 0.937° |
| Longitude of ascending node | 159.647° |
| Argument of perihelion | 251.134° |
| Dimensions | 19.7 km |
| Mass | 8.0×1015 kg |
| Mean density | 2.0 g/cm³ |
| Equatorial surface gravity | 0.0055 m/s² |
| Equatorial escape velocity | 0.0104 km/s |
| Sidereal rotation period |
? d |
| Axial tilt | ?° |
| Pole ecliptic latitude | ? |
| Pole ecliptic longitude | ? |
| Geometric albedo | 0.10 |
| Temperature | ~189 K |
| Spectral type | S |
| Absolute magnitude | 10.79 |
149 Medusa is a bright-coloured, stony main belt asteroid.
It was discovered by J. Perrotin on September 21, 1875 and named after the Gorgon Medusa, a snake-haired monster in Greek mythology.
When it was discovered, Medusa was by far the smallest asteroid found (although this was not known at that time). Since then, many thousands of smaller asteroids have been found. It was also the closest asteroid to the Sun discovered up to that point, beating the long-held record of 8 Flora. It remained the closest asteroid to the Sun until 433 Eros and 434 Hungaria were found in 1898, leading to the discovery of two new families of asteroids inward from the 4:1 Kirkwood gap which forms the boundary of the main belt.
It has also a rather long rotation period of 26 hours.
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