(29075) 1950 DA
Arecibo radio telescope radar image of 1950 DA taken on March 3, 2001, from a distance of 0.052 AU (22 lunar distances)
|
|
| Discovery | |
|---|---|
| Discovered by | Carl A. Wirtanen |
| Discovery date | 22 February 1950 |
| Designations | |
| 2000 YK66 | |
|
Apollo, PHA |
|
| Orbital characteristics | |
| Epoch 17 July 2010 (JD 2455394.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 24122 days (66.04 yr) |
| Aphelion | 2.5614 AU (383.18 Gm) |
| Perihelion | 0.83698 AU (125.210 Gm) |
| 1.6992 AU (254.20 Gm) | |
| Eccentricity | 0.50742 |
| 2.21 yr (809.02 d) | |
|
Average orbital speed
|
21.30 km/s |
| 65.446° | |
| 0° 26m 41.928s / day | |
| Inclination | 12.182° |
| 356.78° | |
| 224.54° | |
| Earth MOID | 0.0403592 AU (6.03765 Gm) |
| Jupiter MOID | 2.47566 AU (370.353 Gm) |
| Physical characteristics | |
| Dimensions | 1.39 x 1.46 x 1.07 km; mean: 1.1 km |
| Mass | >4×1012 kg |
|
Mean density
|
>3.5 g/cm³ |
|
Equatorial surface gravity
|
<0 at equator bulge, due to fast rotation |
| 2.1216 h (0.08840 d) | |
| 0.07 | |
| E or M | |
| 17.1 17.55R |
|
(29075) 1950 DA is a near-Earth asteroid. Among asteroids more than 1 km in diameter, it is notable for having the highest known probability of impacting Earth. In 2002, it had the highest Palermo rating with a value of 0.17 for a possible collision in 2880. Since that time, the estimated risk has been updated several times. In December 2015, the odds of an Earth impact were revised to 1 in 8,330 (0.012%) with a Palermo rating of −1.42. (29075) 1950 DA is not assigned a Torino scale rating, because the 2880 date is over 100 years in the future.
(29075) 1950 DA was first discovered on February 23, 1950, by Carl A. Wirtanen at Lick Observatory. It was observed for seventeen days and then lost because the short observation arc resulted in large uncertainties in Wirtanen's orbital solution. On December 31, 2000, it was recovered as 2000 YK66 and just two hours later was recognized as (29075) 1950 DA.
On March 5, 2001, (29075) 1950 DA made a close approach to Earth at a distance of 0.0520726 AU (7,789,950 km; 4,840,450 mi). It was studied by radar at the Goldstone and Arecibo observatories from March 3 to 7, 2001.
The studies showed that the asteroid has a mean diameter of 1.1 km, assuming that (29075) 1950 DA is a retrograde rotator. Optical lightcurve analysis by Lenka Sarounova and Petr Pravec shows that its rotation period is 2.1216 ± 0.0001 hours. Due to its short rotation period and high radar albedo, (29075) 1950 DA is thought to be fairly dense (more than 3.5 g/cm³) and likely composed of nickel–iron. In August 2014, scientists from the University of Tennessee determined that (29075) 1950 DA is a rubble pile that is kept together by van der Waals forces.
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