4581 Asclepius
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| Discovery A | |
|---|---|
| Discoverer | Henry E. Holt Norman G. Thomas |
| Discovery date | March 31, 1989 |
| Alternate designations B |
1989 FC |
| Category | Apollo asteroid |
| Orbital elements C | |
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| Eccentricity (e) | 0.357 |
| Semi-major axis (a) | 152.890 Gm (1.022 AU) |
| Perihelion (q) | 98.330 Gm (0.657 AU) |
| Aphelion (Q) | 207.449 Gm (1.387 AU) |
| Orbital period (P) | 377.380 d (1.03 a) |
| Mean orbital speed | 28.50 km/s |
| Inclination (i) | 4.910° |
| Longitude of the ascending node (Ω) |
180.452° |
| Argument of perihelion (ω) |
255.106° |
| Mean anomaly (M) | 114.057° |
| Physical characteristics D | |
| Diameter | 300 m |
| Mass | ?×10? kg |
| Density | ? g/cm³ |
| Surface gravity | ? m/s² |
| Escape velocity | ? km/s |
| Rotation period | ? d |
| Spectral class | ? |
| Absolute magnitude | 20.4 |
| Albedo (geometric) | 0.1? |
| Mean surface temperature |
~275 K |
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4581 Asclepius (pronounced /əˈskliːpiəs/ ə-SKLEE-pee-əs) is a small asteroid of the Apollo group that can approach Earth’s orbit to within 600,000 km; it was discovered in 1989 by the American astronomers Henry E. Holt (1929-) and Norman G. Thomas (1930-), and named after the Greek demigod of Medicine and Healing. Asclepius (1989 FC) passed by the Earth on March 22, 1989 at a distance of some 700,000 km, causing some media attention at that time.
The asteroid passed through the exact position where the Earth was only 6 hours before. Astronomers say that had the asteroid hit Earth, the impact would have been equivalent to one Hiroshima-sized atomic bomb detonating every second for 50 days. Subsequent discoveries revealed that a whole class of such objects exists, and that an object the size of the one which just missed Earth in March 1989, probably comes by undetected once every two or three years. "On the cosmic scale of things, that was a close call," said Dr. Henry Holt.
Asclepius will continue to make close approaches to Earth, coming to within 30 Gm 12 times in the 21st century. But the next pass comparable to the 1989 one mentioned above will not take place until 2189, at about 980,000 km.
A paper, authored by Tom Gilchrist, outlining the hazards of a potential impact with Asclepius has recently been published in the leading journal Geoverse.
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