247 Eukrate

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.

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/[a]
Named after	Eucrate
Alternative designations	A885 EB, 1901 TB 1947 TA, 1960 TC
Minor planet category	Main belt
Orbital characteristics[1]
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[1]
Surface area	61580 km2[b]
Volume	1.361×106 km3[c]
Mass	(1.99 ± 0.830/0.62)×1018 kg[2]
Mean density	1.693 ± 0.706/0.527 g/cm3[2][d]
Synodic rotation period	12.093 h (0.5039 d)
Geometric albedo	0.064±0.012[1]
Spectral type	CP
Absolute magnitude (H)	8.20[1]

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

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

References

1. "247 Eukrate". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 12 May 2016.
2. Fienga, A.; Avdellidou, C.; Hanuš, J. (February 2020). "Asteroid masses obtained with INPOP planetary ephemerides". Monthly Notices of the Royal Astronomical Society. 492 (1). doi:10.1093/mnras/stz3407.
3. Magri, Christopher; et al. (January 2007), "A radar survey of main-belt asteroids: Arecibo observations of 55 objects during 1999 2003" (PDF), Icarus, 186 (1): 126–151, Bibcode:2007Icar..186..126M, doi:10.1016/j.icarus.2006.08.018, retrieved 14 April 2015.
4. "PDS Asteroid/Dust Subnode". sbn.psi.edu. Archived from the original on 25 April 2018. Retrieved 19 May 2018.

External links

• The Asteroid Orbital Elements Database
• Minor Planet Discovery Circumstances
• Asteroid Lightcurve Data File
• 247 Eukrate at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 247 Eukrate at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters