astro.wikisort.org - Asteroid

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]

15415 Rika

Discovery[1]
Discovered by	A. Nakamura
Discovery site	Kuma Kogen Obs.
Discovery date	4 February 1998
Designations
MPC designation	(15415) Rika
Named after	Rika Akana (character in the drama Tokyo Love Story)[1]
Alternative designations	1998 CA1 · 1983 PC1 1983 PH · 1997 WK22
Minor planet category	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
Semi-major axis	2.2013 AU
Eccentricity	0.2287
Orbital period (sidereal)	3.27 yr (1,193 d)
Mean anomaly	194.33°
Mean motion	0° 18m 6.48s / day
Inclination	7.4787°
Longitude of ascending node	327.38°
Argument of perihelion	28.661°
Physical characteristics
Mean diameter	2.830±0.488 km[5] 3.74 km (calculated)[4]
Synodic rotation period	6.3636±0.0008 h[6][lower-alpha 1]
Geometric albedo	0.24 (assumed)[4] 0.6053±0.2264[5]
Spectral type	S (assumed)[4]
Absolute magnitude (H)	14.2[2][1] 14.21[5][7] 14.3[4]

Orbit and classification

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 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]

The body'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]

Physical characteristics

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).

Rotation period

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][lower-alpha 1]

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]

The official naming citation was published by the Minor Planet Center on 13 October 2000 (M.P.C. 41388).[8]

Notes

References

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Discovery Circumstances: Numbered Minor Planets (15001)-(20000) – Minor Planet Center
• 15415 Rika at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 15415 Rika at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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