(247) Eukrates
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Asteroid (247) eucrates |
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|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type | Middle main belt |
| Major semi-axis | 2.743 AU |
| eccentricity | 0.244 |
| Perihelion - aphelion | 2.075 AU - 3.411 AU |
| Inclination of the orbit plane | 25 ° |
| Length of the ascending node | 0.2 ° |
| Argument of the periapsis | 54.6 ° |
| Time of passage of the perihelion | January 28, 2011 |
| Sidereal period | 4 a 198 d |
| Mean orbital velocity | 17.7 km / s |
| Physical Properties | |
| Medium diameter | 134 km |
| Albedo | 0.0595 |
| Rotation period | 12 h 6 min |
| Absolute brightness | 8.04 mag |
| Spectral class | CP |
| history | |
| Explorer | KTR Luther |
| Date of discovery | March 14, 1885 |
| Another name | 1947 TA, 1960 TC, A901 TB |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items. | |
(247) Eukrate is an asteroid of the main asteroid belt , which was discovered on March 14, 1885 by Karl Theodor Robert Luther at the Düsseldorf observatory .
The celestial body was named after Eukrate , a daughter of the sea god Okeanos from Greek mythology .
Eukrate moves at a distance of 2.0697 ( perihelion ) to 3.4091 ( aphelion ) astronomical units in 4.5342 years around the sun . The orbit is strongly inclined towards the ecliptic at 24.9933 ° , the orbit eccentricity is 0.2445.
Eukrate has a dark carbon-rich surface with an albedo of 0.06. It rotates around its own axis in 12 hours and 6 minutes.
Radar observations from the Arecibo Observatory in 2001 showed a mean diameter of 134 ± 15 kilometers.
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There are now observations of several star occultations by Eukrates. Observers distributed over the coverage zone measure the times of the disappearance and reappearance of the covered star as precisely as possible - the asteroid itself does not have to be visible in the telescopes used. The figure on the right shows the results obtained by Australian observers for a star occultation by Eukrates on May 12, 2018. The observations are shown as line traces, an interruption in the trace corresponds to the period of occultation at the respective observation site. The resulting gap in the diagram traces the outline of the asteroid shadow, so that the size and shape of the two-dimensional asteroid silhouette at the time of occultation can be read off.
Also drawn is a computer model of the asteroid body, which was derived from observed light curves by Eukrate. The three-dimensional shape, but not the size of the asteroid, can be derived from such light curves. In the illustration, the three-dimensional shape model (rotated according to the view at the time of observation) is adjusted in size so that it fits as well as possible into the two-dimensional outline determined from the coverage. Now that both the three-dimensional shape and the size are known, it can be deduced that the volume of the irregularly shaped eucrates corresponds to the volume of a sphere with a diameter of 137.5 kilometers, while its surface corresponds to the surface of a sphere with a diameter of 140.0 kilometers .
See also
Individual evidence
- ↑ C. Magri, MC Nolan, SJ Ostro, JD Giorgini: A radar survey of main-belt asteroids: Arecibo observations of 55 objects during 1999-2003. Icarus Vol. 186 (2007), pp. 126–151 ( PDF , 1.03 MB)
- ↑ DAMIT: Database of Asteroid Models from Inversion Techniques - Eukrate (accessed May 24, 2018)
- ↑ a b D. Herald: Diameters, Volumes and Bulk Densities of 40 Asteroids. 2017 Annual Meeting of the International Occultation and Timing Association, September 9-10, 2017, Carson City, NV ( PPTX , 2.4 MB)