390 Alma

390 Alma

A three-dimensional model of 390 Alma based on its light curve.
Discovery
Discovered by	Guillaume Bigourdan
Discovery date	March 24, 1894
Designations
Named after	Alma River
Alternative names	1894 BC; 1930 QW; 1950 BV; 1950 CH; 1953 YB; 1963 DF
Minor planet category	Main belt (Eunomia family)
Orbital characteristics
Epoch 30 January 2005 (JD 2453400.5)
Aphelion	448.268 Gm (2.996 AU)
Perihelion	345.512 Gm (2.31 AU)
Semi-major axis	396.89 Gm (2.653 AU)
Eccentricity	0.129
Orbital period	1578.364 d (4.32 a)
Average orbital speed	18.21 km/s
Mean anomaly	258.381°
Inclination	12.144°
Longitude of ascending node	305.342°
Argument of perihelion	190.074°
Physical characteristics
Dimensions	24 km[1]
Mass	~2×1016 kg (estimate)
Mean density	~2.7 g/cm³ (estimate)[3]
Surface gravity	~0.009 m/s² (estimate)
Escape velocity	~0.015 km/s (estimate)
Rotation period	0.156 d [2]
Albedo	0.219
Temperature	~165 K max: 250 K (-23 °C)
Spectral type	S-type asteroid
Absolute magnitude (H)	10.39

390 Alma is a typical medium-sized Eunomian asteroid. It was Guillaume Bigourdan's only asteroid discovery. He discovered it on March 24, 1894 in Paris.

References

1. Supplemental IRAS Minor Planet Survey
2. PDS lightcurve data
3. G. A. Krasinsky et al. Hidden Mass in the Asteroid Belt, Icarus, Vol. 158, p. 98 (2002).