29 Amphitrite

29 Amphitrite

Discovery
Discovered by	A. Marth
Discovery date	March 1, 1854
Designations
Alternative names	A899 NG
Minor planet category	Main belt
Orbital characteristics
Epoch June 14, 2006 (JD 2453900.5)
Aphelion	409.809 Gm (2.739 AU)
Perihelion	354.398 Gm (2.369 AU)
Semi-major axis	382.103 Gm (2.554 AU)
Eccentricity	0.073
Orbital period	1491.013 d (4.08 a)
Average orbital speed	18.61 km/s
Mean anomaly	229.662°
Inclination	6.096°
Longitude of ascending node	356.501°
Argument of perihelion	63.433°
Physical characteristics
Dimensions	212.2 km
Mass	1.0×1019 kg
Mean density	2.0 g/cm³
Surface gravity	0.0593 m/s²
Escape velocity	0.1122 km/s
Rotation period	0.2246 d (5.390 h)
Albedo	0.1793 (geometric)
Temperature	~170 K
Spectral type	S
Apparent magnitude	8.58 to 11.38
Absolute magnitude (H)	5.85
Angular diameter	0.21" to 0.078"

29 Amphitrite is one of the biggest S-type asteroids, probably third in diameter after Eunomia and Juno, although Iris and Herculina are similar in size.

It is probably not a fully solid body, since its density is too low for a solid silicate object and much lower than Eunomia or Juno. Its orbit is less eccentric and inclined than those of its bigger cousins - being indeed the most circular of any asteroid found up to that point - and as a consequence it never becomes as bright as Iris or Hebe, especially as it is much farther from the Sun than those asteroids. It can reach magnitudes of around +8.6 at a favorable opposition, but more usually is around the binocular limit of +9.5.

Amphitrite was found by Albert Marth on March 1, 1854. It was the only asteroid he found. It is named after Amphitrite, a sea goddess in Greek mythology.

A moon is suspected based on the lightcurve data.

Other websites

• Orbital simulation from JPL (Java) / Ephemeris