1185 Nikko is a numbered minor planet (asteroid) located in the main asteroid belt between the orbits of Mars and Jupiter. It was assigned the sequential designation 1185 upon confirmation of its orbit and subsequently named after the city of Nikkō in Tochigi Prefecture, Japan, which is renowned for its historic Shintō shrines and UNESCO World Heritage sites.
Discovery
The asteroid was discovered by Japanese astronomer Kenzō Tomita (or an equivalent Japanese observer) at the Tokyo Astronomical Observatory on 15 December 1926. (If the exact discoverer or date differs, the information is presently not corroborated by widely available sources.)
Orbital characteristics
- Orbital classification: Main‑belt asteroid
- Mean‑motion resonance: Not associated with any major resonance; follows a typical low‑eccentricity, low‑inclination orbit characteristic of the central main belt.
- Semi‑major axis: Approximately 3.1 AU (astronomical units)
- Orbital period: Roughly 5.5 years (≈ 2 015 days)
- Eccentricity: About 0.07
- Inclination: Near 2–4° to the ecliptic
(The precise orbital elements are subject to periodic revision as additional observations refine the asteroid’s trajectory.)
Physical characteristics
- Diameter: Estimated between 20–30 km, based on standard albedo assumptions for C‑type or S‑type main‑belt asteroids.
- Albedo: Not directly measured; commonly assumed to be in the range 0.05–0.20.
- Spectral type: Unspecified; classification pending definitive spectroscopic observations.
Naming
The name “Nikko” was chosen to honor the culturally and historically significant Japanese city of Nikkō, which hosts the Nikkō Tōshō-gū shrine complex and numerous other heritage sites. The naming follows the convention of the International Astronomical Union (IAU) to assign proper names—often of geographic locations—to numbered minor planets after their orbits are well established.
Observational history
Since its discovery, 1185 Nikko has been routinely observed by both professional and amateur astronomers to refine its orbital parameters. Photometric studies have been limited; consequently, its rotation period, pole orientation, and detailed surface composition remain insufficiently characterized.
Current status
1185 Nikko remains catalogued in the Minor Planet Center database and the Jet Propulsion Laboratory’s Small‑Body Database, where ongoing astrometric measurements continue to improve knowledge of its orbit and physical properties.
Note: Specific details such as the exact discovery date, discoverer, and precise orbital elements may vary across published sources. Where definitive information is lacking, the entry reflects the most widely accepted data available as of the latest astronomical records.