A three-dimensional model of 149 Medusa based on its light curve.
|Discovered by||Henri Joseph Perrotin|
|Discovery date||21 September 1875|
|MPC designation||(149) Medusa|
|Orbital characteristics |
|Epoch 31 July 2016 (JD 2457600.5)|
|Uncertainty parameter 0|
|Observation arc||124.55 yr (45493 d)|
|Aphelion||2.3169 AU (346.60 Gm)|
|Perihelion||2.03252 AU (304.061 Gm)|
|2.17472 AU (325.333 Gm)|
|3.21 yr (1171.4 d)|
Average orbital speed
|0° 18m 26.374s / day|
|Earth MOID||1.04123 AU (155.766 Gm)|
|Jupiter MOID||2.87692 AU (430.381 Gm)|
|Jupiter Tisserand parameter||3.683|
Equatorial surface gravity
Equatorial escape velocity
|26.023 h (1.0843 d) 
26.038 h 
|Temperature||~ 189 K|
149 Medusa is a bright-coloured, stony main-belt asteroid that was discovered by French astronomer 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.
Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico, during 2010 gave a light curve with a rather long rotation period of 26.038 ± 0.002 hours and a brightness variation of 0.56 ± 0.03 in magnitude.
- "Discovery Circumstances: Numbered Minor Planets (1)-(5000)". IAU-Minor Planet Center. Retrieved 22 August 2016.
- "The Asteroid Orbital Elements Database". astorb. Lowell Observatory.
- Yeomans, Donald K., "149 Medusa", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
- Pilcher, Frederick (April 2011), "Rotation Period Determinations for 25 Phocaea, 140 Siwa, 149 Medusa 186 Celuta, 475 Ocllo, 574 Reginhild, and 603 Timandra", The Minor Planet Bulletin, 38 (2), pp. 76–78, Bibcode:2011MPBu...38...76P.
- 149 Medusa at the JPL Small-Body Database
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