239 Adrastea

239 Adrastea
Discovery
Discovered by	Johann Palisa
Discovery date	18 August 1884
Designations
MPC designation	(239) Adrastea
Pronunciation	/ædrəˈstiːə/
Named after	Adrasteia
Alternative designations	A915 TD, 1955 MK1,; 1956 UJ
Minor planet category	Main belt
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	131.66 yr (48,087 d)
Aphelion	3.66279 AU (547.946 Gm)
Perihelion	2.2695 AU (339.51 Gm)
Semi-major axis	2.96616 AU (443.731 Gm)
Eccentricity	0.23486
Orbital period (sidereal)	5.11 yr (1,865.9 d)
Average orbital speed	17.25 km/s
Mean anomaly	233.617°
Mean motion	0° 11m 34.584s / day
Inclination	6.1746°
Longitude of ascending node	180.634°
Argument of perihelion	210.15°
Physical characteristics
Dimensions	41.52±1.4 km
Synodic rotation period	18.4707 h (0.76961 d)
Geometric albedo	0.0777±0.006
Temperature	unknown
Spectral type	unknown
Absolute magnitude (H)	10.4

Adrastea (minor planet designation: 239 Adrastea) is a main belt asteroid. It was discovered by Johann Palisa on 18 August 1884 in Vienna, and was named after the Greek nymph Adrasteia. This asteroid is orbiting the Sun at a distance of 2.97 AU with a period of 5.11 years and an eccentricity (ovalness) of 0.23. The orbital plane is tilted at an angle of 6.17° to the plane of the ecliptic.^[1]

Photometric data collected during 2009 were used for light curve analysis of this asteroid, yielding a rotation period of 18.48±0.03 h with a brightness variation of 0.45±0.05 in magnitude. The result is close to the 18.347±0.003 h period from a study performed in 2003.^[2] The asteroid is roughly 42 km in diameter.^[1]

References[]

^ ^a ^b ^c ^d ^e ^f ^g "JPL Small-Body Database Browser: 239 Adrastea". Jet Propulsion Laboratory. Retrieved 12 May 2016.
^ Carbo, Landry; et al. (October 2009), "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory: 2008 October thru 2009 March", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers, 36 (4): 152–157, Bibcode:2009MPBu...36..152C.

External links[]

The Asteroid Orbital Elements Database
Minor Planet Discovery Circumstances
239 Adrastea at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
239 Adrastea at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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[jpldata-1] ^ ^a ^b ^c ^d ^e ^f ^g "JPL Small-Body Database Browser: 239 Adrastea". Jet Propulsion Laboratory. Retrieved 12 May 2016.

[Carbo_et_al_2009-2] Carbo, Landry; et al. (October 2009), "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory: 2008 October thru 2009 March", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers, 36 (4): 152–157, Bibcode:2009MPBu...36..152C.

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