UPSA
Object Registry
Horizons 199
| Parameter | Value | Unit | Uncertainty | As published | Source | Reference |
|---|---|---|---|---|---|---|
| Mass | 3.302 | 1e23 kg | Mass x10^23 (kg) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Mean radius | 2,439.4 | km | Vol. Mean Radius (km) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Equatorial radius | 2,440.53 | re | Equatorial radius, Re | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Density | 5.427 | g cm^-3 | Density (g cm^-3) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Orbital period | 0.2408467 | y | Sidereal orb. per. | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Rotation period | 58.6463 | d | Sidereal rot. period | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Geometric albedo | 0.106 | Geometric Albedo | JPL Horizons | JPL Horizons on-line ephemeris system | ||
| Escape velocity | 4.435 | km/s | Escape vel. km/s | JPL Horizons | JPL Horizons on-line ephemeris system | |
| GM | 22,031.87 | km^3/s^2 | GM (km^3/s^2) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Mean temperature | 440 | K | Mean Temperature (K) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Mean orbital speed | 47.362 | km/s | Mean Orbit vel. km/s | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Mean solar day | 175.9421 | day | Mean solar day | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Surface gravity | 3.701 | m/s^2 | Equ. gravity m/s^2 | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Atmospheric pressure | < 5x10^-15 | bar | Atmos. pressure (bar) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Core radius km | ~1600 | km | Core radius (km) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Hill s sphere rad rp | 94.4 | Hill's sphere rad. Rp | JPL Horizons | JPL Horizons on-line ephemeris system | ||
| Mass ratio sun plnt | 6,023,682 | sun/plnt | Mass ratio (Sun/plnt) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Max angular diam | 11 | " | Max. angular diam. | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Mom of inertia | 0.33 | Mom. of Inertia | JPL Horizons | JPL Horizons on-line ephemeris system | ||
| Sid rot rate rad s | 1.24001e-06 | rad/s | Sid. rot. rate (rad/s) | JPL Horizons | JPL Horizons on-line ephemeris system | |
| Surface emissivity | 0.77 | Surface emissivity | JPL Horizons | JPL Horizons on-line ephemeris system | ||
| Visual mag v 1 0 | -0.42 | Visual mag. V(1,0) | JPL Horizons | JPL Horizons on-line ephemeris system | ||
| Volume x10 10 km 3 | 6.085 | x10^10 km^3 | Volume (x10^10 km^3) | JPL Horizons | JPL Horizons on-line ephemeris system |
| Archive | Read at (UTC) | Record |
|---|---|---|
| JPL Horizons | 2026-08-14 17:08 | open at source |
Machine-readable: /api/v1/object/mercury · Registry entry updated 2026-08-14.