522 Helga

522 Helga

Discovery
Discovered by	Max Wolf
Discovery site	Heidelberg
Discovery date	10 January 1904
Designations
Alternative names	1904 NC
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	114.65 yr (41876 d)
Aphelion	3.9372 AU (589.00 Gm)
Perihelion	3.3284 AU (497.92 Gm)
Semi-major axis	3.6328 AU (543.46 Gm)
Eccentricity	0.083794
Orbital period	6.92 yr (2529.1 d)
Mean anomaly	200.06°
Mean motion	0° 8^m 32.424^s / day
Inclination	4.4174°
Longitude of ascending node	116.683°
Argument of perihelion	246.503°
Earth MOID	2.32811 AU (348.280 Gm)
Jupiter MOID	1.50115 AU (224.569 Gm)
Jupiter Tisserand parameter	3.093
Physical characteristics
Mean radius	50.61±1.75 km
Rotation period	8.129 h (0.3387 d)
Geometric albedo	0.0388±0.003
Absolute magnitude (H)	9.0

522 Helga (also known as 1904 NC) is an asteroid (minor planet) orbiting the Sun discovered in 1904 by Max Wolf in Heidelberg. Helga is notable for being the first such object to be shown to be in a stable but chaotic orbit in resonance with Jupiter, its Lyapunov time being relatively short, at 6,900 yr. Despite this, its orbit appears to be stable, as the eccentricity and precession rates are such that it avoids close encounters with Jupiter.^[2]

522 Helga was "named by Lt. Th. Lassen, orbit computer" according to Paul Herget's The Names of the Minor Planets^[3] (note that computer does not refer to a personal computer, i.e. a machine, but rather to a person actually doing the necessary calculations).

References

1. "522 Helga (1904 NC)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 6 May 2016.
2. Nature
3. Title: Benennung von kleinen Planeten; Journal: Astronomische Nachrichten, volume 169, p.363; Bibliographic Code: 1905AN....169..363.

External links

• 522 Helga at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters