Discovery [1] | |
---|---|
Discovered by | Y. Väisälä |
Discovery site | Turku Obs. |
Discovery date | 18 January 1939 |
Designations | |
(1523) Pieksamaki | |
Named after | Pieksämäki (Finnish town) [2] |
1939 BC · 1936 FO1 1936 HC · 1946 GB 1949 AC | |
main-belt · Flora [3] | |
Orbital characteristics [1] | |
Epoch 4 September 2017 ( JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 80.20 yr (29,294 days) |
Aphelion | 2.4509 AU |
Perihelion | 2.0327 AU |
2.2418 AU | |
Eccentricity | 0.0933 |
3.36 yr (1,226 days) | |
131.04 ° | |
Inclination | 5.1411° |
327.79° | |
187.58° | |
Physical characteristics | |
Dimensions | 8.98 km (calculated)
[3] 9.111±0.313 km [4] 10.008±0.057 km [5] |
5.3202±0.0005
h
[6]
[7] 5.3210±0.0001 h [8] 5.33 h [9] | |
0.2135±0.0277
[5] 0.24 (assumed) [3] 0.281±0.041 [10] 0.505±0.294 [4] | |
S [3] | |
11.56 [4] · 12.3 [5] · 12.4 [1] [3] · 12.58±0.53 [11] | |
1523 Pieksämäki, provisional designation 1939 BC, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 18 January 1939, by Finnish astronomer Yrjö Väisälä at the Turku Observatory in Southwest Finland, and named for the town of Pieksämäki. [2] [12]
This S-type asteroid is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun at a distance of 2.0–2.5 AU once every 3 years and 4 months (1,226 days). Its orbit has an eccentricity of 0.09 and an inclination of 5 ° with respect to the ecliptic. [1] In 1936, it was first identified as 1936 FO1 at Nice Observatory, extending Pieksämäki's observation arc by 3 years prior to its official discovery observation at Turku. [12]
In December 2005, American amateur astronomer Donald P. Pray obtained a rotational lightcurve at Carbuncle Hill Observatory in collaboration with other astronomers. Light-curve analysis gave a well-defined rotation period of 5.3202 hours with a brightness variation of 0.47 magnitude ( U=3). [6]
Previous photometric observations were made by Kryszczyńska et al. in July 2004, that gave an identical period with an amplitude of 0.40 magnitude ( U=2+), [7] and by Claes-Ingvar Lagerkvist, who derived a period of 5.33 hours (Δ0.5 mag) already in the 1970s ( U=2). [9] In March 2013, another well-defined period of 5.3210 hours (Δ0.42 mag) was obtained by French amateur astronomer René Roy. [8]
According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Pieksämäki measures 9.111 and 10.008 kilometers in diameter, and its surface has an albedo between 0.213 and 0.505. [4] [5] [10] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the family's principal body and namesake – and calculates a diameter of 8.98 kilometers based on an absolute magnitude of 12.4. [3]
This minor planet was named for Pieksämäki, an eastern Finnish town in Southern Savonia. [2] The official naming citation was published by the Minor Planet Center on 20 February 1976 ( M.P.C. 3929). [13]