107P/Wilson-Harrington
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Discovery
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| Discovered by | Albert G. Wilson and Robert G. Harrington |
| Discovery date | November 19, 1949 |
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Designations
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| Alternative names | 107P/1949 W1; 107P/1979 VA; 1949 III; 1949g |
| Minor planet category |
Apollo asteroid, Comet |
| Epoch August 18, 2005 (JD 2453600.5) | |
| Aphelion | 640.988 Gm (4.285 AU) |
| Perihelion | 148.542 Gm (0.993 AU) |
| Semi-major axis | 394.765 Gm (2.639 AU) |
| Eccentricity | 0.624 |
| Orbital period | 1565.735 d (4.29 a) |
| Average orbital speed | 16.39 km/s |
| Mean anomaly | 8.800° |
| Inclination | 2.785° |
| Longitude of ascending node | 270.573° |
| Argument of perihelion | 91.281° |
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Physical characteristics
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| Dimensions | ? km |
| Mass | ?×10? kg |
| Mean density | ~2? g/cm³ |
| Equatorial surface gravity | ? m/s² |
| Escape velocity | ? km/s |
| Rotation period | ? d |
| Albedo | 0.10 |
| Temperature | ~171 K |
| Spectral type | ? |
| Absolute magnitude | 15.99 |
Comet Wilson-Harrington is a periodic comet (formally designated 107P/Wilson-Harrington).
Little known about it distinguishes it from other comets, but for the fact that it is also designated an asteroid, 4015 Wilson-Harrington (which, incidentally, is currently the longest asteroid name with 17 characters).
The comet was discovered on November 19, 1949 by Albert G. Wilson and Robert G. Harrington at Palomar Observatory. Only three photographic observations were obtained and the comet was lost (insufficient observations to determine a precise enough orbit to know where to look for future appearances of the comet).
On November 15, 1979 an apparent Mars-crosser asteroid was found by Eleanor F. Helin, also of Palomar Observatory. It received the designation 1979 VA, and when re-observed on December 20, 1988 received the permanent number 4015.
On August 13, 1992 it was reported that asteroid (4015) 1979 VA and comet 107P/Wilson-Harrington were the same object. By then, enough observations of the asteroid had been accumulated to obtain a fairly precise orbit, and the search of old photographic plates for pre-discovery images turned up the 1949 plates with the images of the lost comet.
Although the 1949 images show cometary features, all subsequent images show only a stellar image, suggesting it may be an inactive comet that undergoes only infrequent outbursts.
The eccentricity is 0.624, which is somewhat higher than that of a typical asteroid belt minor planet and more typical of periodic comets.
There are only four other objects that are cross-listed as both comets and asteroids: 2060 Chiron (95P/Chiron), Comet 133P/Elst-Pizarro (7968 Elst-Pizarro), 60558 Echeclus (174P/Echeclus), and 118401 LINEAR (176P/LINEAR (LINEAR 52)).
[edit] External links
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