694 Ekard

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694 Ekard
694Ekard (Lightcurve Inversion).png
A three-dimensional model of 694 Ekard based on its light curve.
Discovery
Discovered by Joel Hastings Metcalf
Discovery site Taunton, Massachusetts
Discovery date 7 November 1909
Designations
1909 JA
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 106.44 yr (38878 d)
Aphelion 3.5372 AU (529.16 Gm)
Perihelion 1.8114 AU (270.98 Gm)
2.6743 AU (400.07 Gm)
Eccentricity 0.32265
4.37 yr (1597.4 d)
201.11°
0° 13m 31.332s / day
Inclination 15.849°
230.116°
111.400°
Earth MOID 0.871633 AU (130.3944 Gm)
Jupiter MOID 2.22568 AU (332.957 Gm)
Jupiter Tisserand parameter 3.251
Physical characteristics
Mean radius
45.39±2 km[1]
45.39 km[2]
5.925 h (0.2469 d)[1][3]
0.046[2]
0.0460±0.004[1]
9.17[1][2]

694 Ekard is a minor planet orbiting the Sun that was discovered by American astronomer Joel Hastings Metcalf on November 7, 1909.

Photometric observations of this asteroid gave a light curve with a period of 5.925 hours and a brightness variation of 0.50 in magnitude.[3] Measurements of the thermal inertia of 694 Ekard give a value of around 100–140 J m−2 K−1 s−1/2, compared to 50 for lunar regolith and 400 for coarse sand in an atmosphere.[2]

13-cm radar observations of this asteroid from the Arecibo Observatory between 1980 and 1985 were used to produce a diameter estimate of 101 km.[4]

References[edit]

  1. ^ a b c d e Yeomans, Donald K., "694 Ekard", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 7 May 2016. 
  2. ^ a b c d Delbo', Marco; Tanga, Paolo (February 2009), "Thermal inertia of main belt asteroids smaller than 100 km from IRAS data", Planetary and Space Science 57 (2), pp. 259–265, arXiv:0808.0869, Bibcode:2009P&SS...57..259D, doi:10.1016/j.pss.2008.06.015. 
  3. ^ a b Zeigler, K. W.; Florence, W. B. (June 1985), "Photoelectric photometry of asteroids 9 Metis, 18 Melpomene, 60 Echo, 116 Sirona, 230 Athamantis, 694 Ekard, and 1984 KD", Icarus 62, pp. 512–517, Bibcode:1985Icar...62..512Z, doi:10.1016/0019-1035(85)90191-5. 
  4. ^ Ostro, S. J.; et al. (August 1985), "Mainbelt asteroids - Dual-polarization radar observations", Science 229 (4712), pp. 442–446, Bibcode:1985Sci...229..442O, doi:10.1126/science.229.4712.442, PMID 17738665. 

External links[edit]