Astronomy:522 Helga
| Discovery | |
|---|---|
| Discovered by | Max Wolf |
| Discovery site | Heidelberg Observatory |
| Discovery date | 10 January 1904 |
| Designations | |
| (522) Helga | |
| Pronunciation | German: [ˈhɛlɡaː][1] |
| 1904 NC | |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 114.65 yr (41876 d) |
| |{{{apsis}}}|helion}} | 3.9372 astronomical unit|AU (589.00 Gm) |
| |{{{apsis}}}|helion}} | 3.3284 AU (497.92 Gm) |
| 3.6328 AU (543.46 Gm) | |
| Eccentricity | 0.083794 |
| Orbital period | 6.92 yr (2529.1 d) |
| Mean anomaly | 200.06° |
| Mean motion | 0° 8m 32.424s / day |
| Inclination | 4.4174° |
| Longitude of ascending node | 116.683° |
| 246.503° | |
| 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 |
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 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
- ↑ (German Names)
- ↑ "522 Helga (1904 NC)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=522;cad=1.
- ↑ Milani, Andrea; Nobili, Anna M. (June 1992). "An example of stable chaos in the Solar System" (in en). Nature 357 (6379): 569–571. doi:10.1038/357569a0. ISSN 1476-4687. Bibcode: 1992Natur.357..569M. https://www.nature.com/articles/357569a0.
- ↑ Lagerkvist, Claes-Ingvar et al. (January 2001), "A Study of Cybele Asteroids. I. Spin Properties of Ten Asteroids", Icarus 149 (1): 190–197, doi:10.1006/icar.2000.6507, Bibcode: 2001Icar..149..190L.
- ↑ Title: Benennung von kleinen Planeten; Journal: Astronomische Nachrichten, volume 169, p.363; Bibliographic Code: 1905AN....169..363.
External links
- 522 Helga at AstDyS-2, Asteroids—Dynamic Site
- 522 Helga at the JPL Small-Body Database
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