1996 PW

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]

1996 PW
Discovery images of 1996 PW from NEAT-GEODSS in August 1996
Discovery [1][2]
Discovered byNEAT
Discovery siteHaleakala Obs.
Discovery date9 August 1996
Designations
1996 PW
TNO [3] · damocloid [4][5]
distant [1] · unusual [6]
Orbital characteristics [3]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 2
Observation arc1.39 yr (506 d)
Aphelion504.23 AU
Perihelion2.4933 AU
253.36 AU
Eccentricity0.9902
4033 yr (1,473,017 d)
2.0281°
0° 0m 0.72s / day
Inclination29.956°
144.38°
181.60°
TJupiter1.7130
Physical characteristics
Mean diameter
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]
14.0[1][3]

    Description
    Discovery images of 1996 PW from NEAT-GEODSS in August 1996

    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]

    See also

    References
    1. "1996 PW". Minor Planet Center. Retrieved 17 January 2018.
    2. Weissman, Paul R.; Lecison, Harold F. (March 1997). "Origin and evolution of the unusual object 1996 PW". Conference Paper. 488 (2): 529. Bibcode:1997LPI....28.1529W. doi:10.1086/310940.
    3. "JPL Small-Body Database Browser: (1996 PW)" (1997-12-28 last obs.). Jet Propulsion Laboratory. Retrieved 17 January 2018.
    4. Johnston, Wm. Robert (15 October 2017). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 17 January 2018.
    5. Akimasa Nakamura (2 May 2009). "Table of Damocloid objects, or Oort cloud asteroids". Lowell Observatory. Retrieved 17 January 2018.
    6. "List Of Other Unusual Objects". Minor Planet Center. Retrieved 14 November 2018.
    7. "LCDB Data for (1996+PW)". Asteroid Lightcurve Database (LCDB). Retrieved 20 November 2018.
    8. Davies, John K.; McBride, Neil; Green, Simon F.; Mottola, Stefano; Carsenty, Uri; Basran, Devinder; et al. (April 1998). "The Lightcurve and Colors of Unusual Minor Planet 1996 PW". Icarus. 132 (2): 418–430. Bibcode:1998Icar..132..418D. doi:10.1006/icar.1998.5888.
    9. Bus, Schelte J.; Binzel, Richard P. (July 2002). "Phase II of the Small Main-Belt Asteroid Spectroscopic Survey. A Feature-Based Taxonomy" (PDF). Icarus. 158 (1): 146–177. Bibcode:2002Icar..158..146B. doi:10.1006/icar.2002.6856. Archived from the original (PDF) on 23 September 2015. Retrieved 20 November 2018.
    10. Toth, Imre (December 2005). "Connections between asteroids and cometary nuclei". Asteroids. 1: 67–96. Bibcode:2006IAUS..229...67T. doi:10.1017/S174392130500668X.
    11. Hicks, M. D.; Buratti, B. J.; Newburn, R. L.; Rabinowitz, D. L. (February 2000). "Physical Observations of 1996 PW and 1997 SE5: Extinct Comets or D-Type Asteroids?". Icarus. 143 (2): 354–359. Bibcode:2000Icar..143..354H. doi:10.1006/icar.1999.6258.

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