1218 Aster, provisional designation 1932 BJ, is a bright asteroid from the inner regions of the asteroid belt, approximately 5.5 kilometers in diameter. Discovered by Karl Reinmuth in 1932, it was later named after the flowering plant Aster.
![]() Shape model of Aster from its lightcurve | |
Discovery[1] | |
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Discovered by | K. Reinmuth |
Discovery site | Heidelberg Obs. |
Discovery date | 29 January 1932 |
Designations | |
MPC designation | (1218) Aster |
Pronunciation | /ˈæstər/[2] |
Named after | Aster (genus of flowers)[3] |
Alternative designations | 1932 BJ · 1978 TJ5 1978 VQ12 |
Minor planet category | main-belt · (inner) |
Orbital characteristics[1] | |
Epoch 4 September 2017 (JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 85.35 yr (31,173 days) |
Aphelion | 2.5110 AU |
Perihelion | 2.0158 AU |
Semi-major axis | 2.2634 AU |
Eccentricity | 0.1094 |
Orbital period (sidereal) | 3.41 yr (1,244 days) |
Mean anomaly | 56.714° |
Mean motion | 0° 17m 21.84s / day |
Inclination | 3.1572° |
Longitude of ascending node | 63.820° |
Argument of perihelion | 69.372° |
Physical characteristics | |
Dimensions | 5.554±0.084 km[4] |
Geometric albedo | 0.332±0.043[4] |
Absolute magnitude (H) | 13.2[1] |
Aster was discovered on 29 January 1932, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany.[5] Two nights later, it was independently discovered by Italian astronomer Mario A. Ferrero at the Pino Torinese Observatory at Turin, Italy.[3]
Aster orbits the Sun in the inner main-belt at a distance of 2.0–2.5 AU once every 3 years and 5 months (1,244 days). Its orbit has an eccentricity of 0.11 and an inclination of 3° with respect to the ecliptic.[1]
The asteroid's observation arc begins at the discovering observatory, one week after its official discovery observation.[5]
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Aster measures 5.554 kilometers in diameter and its surface has an albedo of 0.332.[4]
As of 2017, rotational lightcurve of Aster has been obtained.[6] The body's rotation period, shape and variation in magnitude shifted from unknown movements[1][7] to specific identifiable spin/shape determinations.
The minor planet was named after the genus of flowers, Aster (also see List of minor planets named after animals and plants § Plants). The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 113).[3]
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