 Composite image of Mercury taken by MESSENGER |
Designations |
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Pronunciation |
/ˈmɜrkjəri/ |
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Adjective |
Mercurian, Mercurial[१] |
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Orbital characteristics[४] |
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Epoch J2000 |
Aphelion |
- 69,816,900 km
- 0.466 697 AU
|
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Perihelion |
- 46,001,200 km
- 0.307 499 AU
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Semi-major axis |
- 57,909,100 km
- 0.387 098 AU
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Eccentricity |
0.205 630[२] |
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Orbital period |
|
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Synodic period |
115.88 d[२] |
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Average orbital speed |
47.87 km/s[२] |
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Mean anomaly |
174.796° |
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Inclination |
|
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Longitude of ascending node |
48.331° |
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Argument of perihelion |
29.124° |
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Satellites |
None |
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Physical characteristics |
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Mean radius |
- 2,439.7 ± 1.0 km[५][६]
- 0.3829 Earths
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Flattening |
0[६] |
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Surface area |
- 7.48×10७ km2[५]
- 0.147 Earths
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Volume |
- 6.083×10१० km3[५]
- 0.056 Earths
|
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Mass |
- 3.3022×10२३ kg[५]
- 0.055 Earths
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Mean density |
5.427 g/cm3[५] |
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Equatorial surface gravity |
|
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Escape velocity |
4.25 km/s[५] |
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Sidereal rotation period |
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Equatorial rotation velocity |
10.892 km/h (3.026 m/s) |
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Axial tilt |
2.11′ ± 0.1′[७] |
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North pole right ascension |
- 18 h 44 min 2 s
- 281.01°[२]
|
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North pole declination |
61.45°[२] |
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Albedo |
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Surface temp. |
min |
mean |
max |
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0°N, 0°W [११] |
100 K |
340 K |
700 K |
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85°N, 0°W[११] |
80 K |
200 K |
380 K |
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Apparent magnitude |
−2.6[९] to 5.7[२][१०] |
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Angular diameter |
4.5" – 13"[२] |
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Atmosphere[२] |
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Surface pressure |
trace |
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Composition |
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