(29075) 1950 DA
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| Discovery A | |
|---|---|
| Discoverer | Carl A. Wirtanen |
| Discovery date | February 23, 1950 |
| Alternate designations B |
2000 YK66 |
| Category | Apollo |
| Orbital elements C | |
|
|
|
| Eccentricity (e) | 0.508 |
| Semi-major axis (a) | 254.133 Gm (1.699 AU) |
| Perihelion (q) | 125.117 Gm (0.836 AU) |
| Aphelion (Q) | 383.148 Gm (2.561 AU) |
| Orbital period (P) | 808.726 d (2.21626 a) |
| Mean orbital speed | 21.30 km/s |
| Inclination (i) | 12.184° |
| Longitude of the ascending node (Ω) |
356.802° |
| Argument of perihelion (ω) |
224.503° |
| Mean anomaly (M) | 75.965° |
| Physical characteristics D | |
| Dimensions | 1.1–1.4 km |
| Mass | ? kg |
| Density | 3.0 + g/cm³ |
| Surface gravity | ? m/s² |
| Escape velocity | ? km/s |
| Rotation period | 0.0884 d (2.1216 h) |
| Spectral class | E or M |
| Absolute magnitude | 17.0 |
| Albedo (geometric) | 0.2-0.25 |
| Mean surface temperature |
? K |
(29075) 1950 DA is the near Earth object with the highest known possible probability of impacting Earth, according to the Palermo Technical Impact Hazard Scale. For a few days in December 2004 it was temporarily surpassed by 99942 Apophis (which at the time was named only by its provisional designation 2004 MN4).
1950 DA was first discovered on February 23, 1950 by Carl A. Wirtanen at Lick Observatory. It was observed for 17 days and then lost for half a century. An object discovered on December 31, 2000 (provisionally designated 2000 YK66) was recognized as being the 1950 DA.
The asteroid has been given the number 29075, but does not have a name. Wirtanen had naming rights as the original discoverer. Upon his death, naming rights reverted to the IAU, which may assign a name in the future.
[edit] General information
Radar observations at the Goldstone and Arecibo Observatory from March 3 to 7, 2001 during the asteroid's 7.8 million km approach to the Earth give a mean diameter of 1.1 – 1.4 km. Optical lightcurves by Petr Pravec show that the asteroid rotates every 2.1216 hours.
Due to its short rotation period, 1950 DA is thought to be fairly dense (more than 3.0 g/cm³).
If 1950 DA continues on its present orbit, it will approach near to the Earth on March 16, 2880. Over the intervening time, the rotation of the asteroid will cause its orbit to change (by the Yarkovsky effect). A preliminary analysis shows two possible pole directions (Giorgini, et al., 2002 "Asteroid 1950 DA's 2880 Encounter with Earth"). One trajectory misses the Earth by tens of millions of kilometers, while the other has an impact probability of 1⁄300. The radar observations are currently being reanalyzed, in combination with the optical lightcurves.
The energy released by a collision with an object the size of 1950 DA would cause major effects on the climate and biosphere which would be devastating to human civilization.
The discovery of the potential impact has heightened interest in asteroid deflection strategies.
[edit] See also
[edit] External links
- NASA Near Earth Object Program: Asteroid 1950 DA
- Article on the effects of a hypothetical impact, with particular relation to a predicted megatsunami (Geophysical Journal International)
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| Previous minor planet | (29075) 1950 DA | Next minor planet |
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| Vulcanoids | Near-Earth asteroids | Main belt | Jupiter Trojans | Centaurs | Damocloids | Comets | Trans-Neptunians (Kuiper belt · Scattered disc · Oort cloud) |
| For other objects and regions, see: asteroid groups and families, binary asteroids, asteroid moons and the Solar system For a complete listing, see: List of asteroids. See also Pronunciation of asteroid names and Meanings of asteroid names. |
