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 November 7, 1909
Designations
1909 JA
Orbital characteristics[1]
Epoch August 18, 2005 (JDCT 2453600.5)
Aphelion 3.536 AU
Perihelion 1.803 AU
2.670 AU
Eccentricity 0.325
4.362 a
17.503°
Inclination 15.842°
230.429°
110.962°
Physical characteristics
Dimensions 90.780[2] km
5.925[3]
Albedo 0.046[2]
9.17[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. ^ Yeomans, Donald K., "694 Ekard", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30. 
  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): 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: 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: 442-446, Bibcode:1985Sci...229..442O, doi:10.1126/science.229.4712.442. 

External links[edit]