| Discovery [1] | |
|---|---|
| Discovered by | A. Nakamura |
| Discovery site | Kuma Kogen Obs. |
| Discovery date | 4 February 1998 |
| Designations | |
| (15415) Rika | |
Named after | Rika Akana (character in the drama Tokyo Love Story ) [1] |
| 1998 CA1 ·1983 PC1 1983 PH ·1997 WK22 | |
| main-belt [1] [2] ·(inner) background [3] · Flora [4] | |
| Orbital characteristics [2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 63.41 yr (23,161 d) |
| Aphelion | 2.7047 AU |
| Perihelion | 1.6979 AU |
| 2.2013 AU | |
| Eccentricity | 0.2287 |
| 3.27 yr (1,193 d) | |
| 194.33° | |
| 0° 18m 6.48s / day | |
| Inclination | 7.4787° |
| 327.38° | |
| 28.661° | |
| Physical characteristics | |
| 2.830±0.488 km [5] 3.74 km(calculated) [4] | |
| 6.3636±0.0008 h [6] [a] | |
| 0.24(assumed) [4] 0.6053±0.2264 [5] | |
| S (assumed) [4] | |
| 14.2 [2] [1] 14.21 [5] [7] 14.3 [4] | |
15415 Rika (provisional designation 1998 CA1) is a bright background asteroid from the Florian region of the inner asteroid belt, approximately 3 kilometers (2 miles) in diameter. It was discovered on 4 February 1998, by Japanese astronomer Akimasa Nakamura at the Kuma Kogen Astronomical Observatory in southern Japan. [1] The presumed S-type asteroid has a rotation period of 6.36 hours and possibly an elongated shape. [4] It was named after Rika Akana, a character in the Japanese film and later television adapted drama Tokyo Love Story . [1]
Rika is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. [3] Based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Flora family ( 402 ), a giant asteroid family and the largest family of stony asteroids in the main-belt. [4]
It orbits the Sun in the inner asteroid belt at a distance of 1.7–2.7 astronomical units (AU) once every 3 years and 3 months (1,193 days; semi-major axis of 2.2 AU). Its orbit has an eccentricity of 0.23 and an inclination of 7° with respect to the ecliptic. [2]
Rika's observation arc begins with a precovery published by the Digitized Sky Survey and taken at the Palomar Observatory in November 1954, more than 43 years prior to its official discovery observation at Kuma Kogen. [1]
Rika is an assumed, common S-type asteroid, [4] despite the exceptionally high albedo (see below) measured by the Wide-field Infrared Survey Explorer (WISE).
In October 2006, a rotational lightcurve of Rika was obtained from photometric observations by astronomers at the Skalnaté pleso Observatory in Slovakia. Lightcurve analysis gave a well-defined rotation period of 6.3636 hours with a high brightness amplitude of 1.06 magnitude, indicating that the body has an elongated shape ( U=3 ). [6] [a]
According to the survey carried out by the NEOWISE mission of NASA's WISE telescope, Rika measures 2.830 kilometers in diameter and its surface has a high albedo of 0.6053. [5] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the parent body of the Flora family – and calculates a diameter of 3.74 kilometers based on an absolute magnitude of 14.3. [4]
This minor planet was named after Rika Akana, the heroine played by Honami Suzuki in the manga-based Japanese television drama Tokyo Love Story . Some episodes of the dorama were filmed on locations near the town of Kumakōgen, where the discovering observatory of this asteroid is located. [1]
The official naming citation was published by the Minor Planet Center on 13 October 2000 ( M.P.C. 41388). [8]
