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]
It orbits the Sun in the inner asteroid belt at a distance of 1.7–2.7 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]
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]
Diameter and albedo
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]
Naming
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]
^ abPravec (2006) Lightcurve plot of (15415) Rika by Husárik and Kusnirák, from Ondrejov data published by the NEO Photometric Program and collaborating projects: rotation period 6.3632±0.0007 hours (basically identical with 6.3636±0.0008 h) and a brightness amplitude of 1.06 mag. Quality code is 3. Summary figures at the LCDB.
