817 Annika

817 Annika

Discovery
Discovered by	Max Wolf
Discovery date	6 February 1916
Designations
Alternative names	1916 YW
Minor planet category	Main belt (Eunomia family)
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	100.19 yr (36596 d)
Aphelion	3.0538 AU (456.84 Gm)
Perihelion	2.1292 AU (318.52 Gm)
Semi-major axis	2.5915 AU (387.68 Gm)
Eccentricity	0.17840
Orbital period	4.17 yr (1523.8 d)
Average orbital speed	18.36 km/s
Mean anomaly	90.5151°
Mean motion	0° 14^m 10.5^s / day
Inclination	11.336°
Longitude of ascending node	125.626°
Argument of perihelion	284.728°
Earth MOID	1.17168 AU (175.281 Gm)
Jupiter MOID	2.38185 AU (356.320 Gm)
Jupiter Tisserand parameter	3.370
Physical characteristics
Mean radius	11.025±0.85 km,[1] 11 km[2]
Mass	~1.5×10^16 kg (estimate)
Mean density	~2.7 g/cm³ (estimate)[3]
Equatorial surface gravity	~0.008 m/s² (estimate)
Equatorial escape velocity	~0.013 km/s (estimate)
Rotation period	0.440 d,[4] 10.56 h (0.440 d)[1]
Geometric albedo	0.1740±0.030
Temperature	~169 K max: 264K (-9° C)
Spectral type	S-type asteroid
Absolute magnitude (H)	10.6

817 Annika is a mid-sized Eunomian asteroid.

References

1. "817 Annika (1916 YW)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 4 May 2016.
2. "Supplemental IRAS Minor Planet Survey".
3. G. A. Krasinsky; et al. (2002). "Hidden Mass in the Asteroid Belt". Icarus 158: 98.
4. "PDS lightcurve data".

External links

• Discovery Circumstances: Numbered Minor Planets
• 817 Annika at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters