247 Eukrate

247 Eukrate
	3D model based on lightcurve data
Discovery
Discovered by	Robert Luther
Discovery date	14 March 1885
Designations
MPC designation	(247) Eukrate
Pronunciation	/juːˈkreɪtiː/
Named after	Eucrate
Alternative designations	A885 EB, 1901 TB; 1947 TA, 1960 TC
Minor planet category	Main belt
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	131.09 yr (47880 d)
Aphelion	3.4086 AU (509.92 Gm)
Perihelion	2.0778 AU (310.83 Gm)
Semi-major axis	2.7432 AU (410.38 Gm)
Eccentricity	0.24257
Orbital period (sidereal)	4.54 yr (1659.5 d)
Average orbital speed	18.0 km/s
Mean anomaly	75.9892°
Mean motion	0° 13m 0.948s / day
Inclination	24.991°
Longitude of ascending node	0.16410°
Argument of perihelion	54.969°
Physical characteristics
Mean diameter	130.935±0.505 km
Surface area	61580 km2
Volume	1.361×106 km3
Mass	(1.99 ± 0.830/0.62)×1018 kg
Mean density	1.693 ± 0.706/0.527 g/cm3
Synodic rotation period	12.093 h (0.5039 d)
Geometric albedo	0.064±0.012
Spectral type	CP
Absolute magnitude (H)	8.20

247 Eukrate is a rather large main-belt asteroid. It is dark and probably a primitive carbonaceous body. The asteroid was discovered by Robert Luther on March 14, 1885, in Düsseldorf. It was named after Eucrate, a Nereid in Greek mythology.

In 2001, the asteroid was detected by radar from the Arecibo Observatory at a distance of 1.18 AU. The resulting data yielded an effective diameter of 134 ± 15 km.^[3]

An Occult (Software) plot of 5 Occultation chords (and a miss) with DAMIT Inversion model at event time.

There have been 9 occultation observations of this asteroid since 2004.^[4] The latest of 2018 May 12 was a 5 chord observation that allows, using Occult (Software), the scaling of the DAMIT model 1207, to yield a mean volume-equivalent diameter of 137.5 km and a mean surface-equivalent diameter of 140.0 km.

Notes

^ A rare case of a long alpha in Greek, eukrātē,[1] so the stress is on the 'a'. Cf. "eucratic". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
^ Surface area derived from the surface area equivalent diameter d: $\pi d^{2}$ , where d = 140.0 km.
^ Volume derived from the volume equivalent diameter d: ${\frac {\pi }{6}}d^{3}$ , where d = 137.5 km.
^ Assuming a diameter of 130.935 ± 0.505 km.