522 Helga

Helga (minor planet designation: 522 Helga), provisional designation 1904 NC is a large main belt asteroid (minor planet). It was 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.[3] It forms part of the Cybele asteroid group.[4]

522 Helga
Discovery
Discovered byMax Wolf
Discovery siteHeidelberg Observatory
Discovery date10 January 1904
Designations
(522) Helga
PronunciationGerman: [ˈhɛlɡaː][1]
1904 NC
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc114.65 yr (41876 d)
Aphelion3.9372 AU (589.00 Gm)
Perihelion3.3284 AU (497.92 Gm)
3.6328 AU (543.46 Gm)
Eccentricity0.083794
6.92 yr (2529.1 d)
200.06°
0° 8m 32.424s / day
Inclination4.4174°
116.683°
246.503°
Physical characteristics
Mean radius
50.61±1.75 km
8.129 h (0.3387 d)
0.0388±0.003
9.0

    522 Helga was "named by Lt. Th. Lassen, orbit computer" according to Paul Herget's The Names of the Minor Planets[5] (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. (German Names)
    2. "522 Helga (1904 NC)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 6 May 2016.
    3. Milani, Andrea; Nobili, Anna M. (June 1992). "An example of stable chaos in the Solar System". Nature. 357 (6379): 569–571. Bibcode:1992Natur.357..569M. doi:10.1038/357569a0. ISSN 1476-4687. S2CID 4367823.
    4. Lagerkvist, Claes-Ingvar; et al. (January 2001), "A Study of Cybele Asteroids. I. Spin Properties of Ten Asteroids", Icarus, 149 (1): 190–197, Bibcode:2001Icar..149..190L, doi:10.1006/icar.2000.6507.
    5. Title: Benennung von kleinen Planeten; Journal: Astronomische Nachrichten, volume 169, p.363; Bibliographic Code: 1905AN....169..363.


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