1996 PW
Small Solar System body, likely from the Oort cloud, but without cometary activity
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1996 PW is an exceptionally eccentric trans-Neptunian object and damocloid on an orbit typical of long-period comets but one that showed no sign of cometary activity around the time it was discovered.[8] The unusual object measures approximately 10 kilometers (6 miles) in diameter and has a rotation period of 35.4 hours and likely an elongated shape.[7]
| |
| Discovery[1][2] | |
|---|---|
| Discovered by | NEAT |
| Discovery site | Haleakala Obs. |
| Discovery date | 9 August 1996 |
| Designations | |
| 1996 PW | |
| TNO[3] · damocloid[4][5] distant[1] · unusual[6] | |
| Orbital characteristics[3] | |
| Epoch 21 November 2025 (JD 2461000.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 1.43 yr (524 d) |
| Aphelion | 541.93 AU |
| Perihelion | 2.5698 AU |
| 272.25 AU | |
| Eccentricity | 0.9906 |
| 4492 yr (1,640,761 d) | |
| 2.3480° | |
| 0° 0m 0.72s / day | |
| Inclination | 29.691° |
| 144.61° | |
| 181.88° | |
| TJupiter | 1.742 |
| Physical characteristics | |
| 7 km[4] 8 km (est. at 0.15)[2] 15 km (est. at 0.04)[2] | |
| 35.44 h[7][8] | |
| Ld (SMASS)[3][7][9] D[8][10] B–R = 0.56±0.04 V–I = 1.03±0.06 V–J = 1.80±0.05 V–H = 2.19±0.05 V–K = 2.32±0.05[8] | |
| 13.9[1][3] | |
Description
1996 PW orbits the Sun at a distance of 2.5–504 AU once every 4,033 years (semi-major axis of 253 AU). Its orbit has an eccentricity of 0.99 and an inclination of 30° with respect to the ecliptic.[3]
Simulations indicate that it has most likely come from the Oort cloud, with a roughly equal probability of being an extinct comet and a rocky body that was originally scattered into the Oort cloud. The discovery of 1996 PW prompted theoretical research that suggests that roughly 1 to 2 percent of the Oort cloud objects are rocky.[2][10]
1996 PW was first observed on 9 August 1996 by the Near-Earth Asteroid Tracking (NEAT) automated search camera on Haleakala Observatory, Hawaii. It is the first object that is not an active comet discovered on an orbit typical of long-period comets.[2]
1996 PW has a rotation period of 35.44±0.02 hours and a double-peaked lightcurve with a high amplitude of 0.44±0.03 magnitude (U=3).[7][8] Its spectrum is moderately red and featureless,[11] typical of D-type asteroids and bare comet nuclei.[8][10][11] Its spectrum suggests an extinct comet.[11] The upper limit on 1996 PW's dust production is 0.03 kg/s.[8]