694 Ekard
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| Discovery | |
|---|---|
| Discovered by | Joel Hastings Metcalf |
| Discovery site | Taunton, Massachusetts |
| Discovery date | November 7, 1909 |
| Designations | |
| Alternative names | 1909 JA |
| Orbital characteristics[1] | |
| Epoch August 18, 2005 (JDCT 2453600.5) | |
| Aphelion | 3.536 AU |
| Perihelion | 1.803 AU |
| Semi-major axis | 2.670 AU |
| Eccentricity | 0.325 |
| Orbital period | 4.362 a |
| Mean anomaly | 17.503° |
| Inclination | 15.842° |
| Longitude of ascending node | 230.429° |
| Argument of perihelion | 110.962° |
| Physical characteristics | |
| Dimensions | 90.780[2] km |
| Rotation period | 5.925[3] |
| Albedo | 0.046[2] |
| Absolute magnitude (H) | 9.17[2] |
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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
- ↑ Yeomans, Donald K., "694 Ekard", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30.
- ↑ 2.0 2.1 2.2 2.3 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.
- ↑ 3.0 3.1 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.
- ↑ 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
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