1998 WW31, is a non-resonant trans-Neptunian object and binary system from the Kuiper belt located in the outermost region of the Solar System, approximately 148 kilometers (92 miles) in diameter. It was first observed on 18 November 1998, by American astronomer Marc Buie and Robert Millis at the Kitt Peak National Observatory in Arizona, United States.[2][3][1] In December 2000, a minor-planet moon, designated S/2000 (1998 WW31) 1 with a diameter of 123 kilometers (76 miles), was discovered in its orbit.[7] After Charon in 1978, it was the first of nearly 100 satellites since discovered in the outer Solar System.[3][7]
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| Discovery[1] | |
|---|---|
| Discovered by | M. W. Buie[2] R. L. Millis[3] |
| Discovery site | Kitt Peak Obs. |
| Discovery date | 18 November 1998 (first observed only) |
| Designations | |
| 1998 WW31 | |
| TNO[2][4] · cubewano (hot)[5] distant[1] · binary[6] | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 4 | |
| Observation arc | 20.94 yr (7,647 d) |
| Aphelion | 48.526 AU |
| Perihelion | 40.429 AU |
| 44.477 AU | |
| Eccentricity | 0.09102 |
| 296.63 yr (108,345 d) | |
| 141.847° | |
| 0° 0m 11.963s / day | |
| Inclination | 6.8171° |
| 237.138° | |
| 51.218° | |
| Known satellites | 1 (D: 123 km; P: 587 d)[6][7] |
| Physical characteristics | |
| 148 km (est. primary)[5][6] 192.1 km (cal. system)[8] | |
| Mass | (2.658±0.015)×1018 kg[9] |
| 0.04 (est.)[10] 0.10 (assumed)[8] | |
| blue[10] C (assumed)[8] V–I = 0.910±0.020[11] | |
| 6.7[4][8] 6.9[10] | |
Orbit and classification
editLocated beyond the orbit of Neptune, 1998 WW31 is a non-resonant classical Kuiper belt object (cubewano) of the so-called hot population, which have higher inclinations than those of the cold population.[5][12] It orbits the Sun at a distance of 40.4–48.5 AU once every 297 years (108,345 days; semi-major axis of 44.48 AU). Its orbit has an eccentricity of 0.09 and an inclination of 7° with respect to the ecliptic.[4] The body's observation arc begins at Kitt Peak with its first observation on 18 November 1998.[1]
Numbering and naming
editAs of 2018, this minor planet has not been numbered nor named by the Minor Planet Center.[1]
Physical characteristics
edit1998 WW31 is expected to have a low albedo due to its blue (neutral) color.[10] Other sources assume a higher albedo of 0.10 and 0.16, respectively (see below).[6][8] It has a V–I color index of 0.91,[11] notably lower than the mean-color index for cubewanos, and in between that of comets and Jupiter trojans.[13]: 35
Satellite
edit1998 WW31 is a binary minor planet with a minor-planet moon in its orbit. On 22 December 2000, French astronomers Christian Veillet and Alain Doressoundiram in collaboration with J. Shapiro discovered the satellite using the Canada–France–Hawaii Telescope at Mauna Kea on the Big Island of Hawaii, United States. The discovery was announced on 16 April 2001 and received the provisional designation S/2000 (1998 WW31) 1.[7]
It was the first trans-Neptunian binary discovered after Charon in 1978, the largest satellite in the Pluto–Charon system.[3] Since then nearly 100 trans-Neptunian binaries have been discovered. 1998 WW31 is also one of the most symmetrical binaries known in the Solar System.
The satellite has a highly eccentric orbit with eccentricity of 0.8193±0.0020 with an exceptionally long orbital period of 587.27±0.18 d and a semi-major axis of 22617±42 km.[9]
Diameter and albedo
editWhile the primary measures 148 kilometres (92 mi), the satellite has a diameter of 123 kilometres (76 mi) (a ratio of 0.883) with a combined system diameter of 192 kilometres (119 mi).[6][12] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.10 and calculates a system diameter of 192 kilometres (119 mi) based on an absolute magnitude of 6.7,[8] while Mike Brown finds a diameter of 267 kilometres (166 mi) with a lower albedo of 0.04.[10]
Rotation period
editAs of 2020, no rotational lightcurve of 1998 WW31 has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[8][12]
References
edit- ^ a b c d e "1998 WW31". Minor Planet Center. Retrieved 10 October 2018.
- ^ a b c "List Of Transneptunian Objects". Minor Planet Center. Retrieved 10 October 2018.
- ^ a b c d "The binary Kuiper-belt object 1998 WW31" (PDF). Nature. 18 April 2002. Retrieved 10 October 2018.
- ^ a b c d "JPL Small-Body Database Browser: (1998 WW31)" (2011-12-24 last obs.). Jet Propulsion Laboratory. Retrieved 10 October 2018.
- ^ a b c Johnston, Wm. Robert (30 December 2017). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 10 October 2018.
- ^ a b c d e Johnston, Wm. Robert (31 January 2015). "Asteroids with Satellites Database – 1998 WW31 and S/2000 (1998 WW31) 1". Johnston's Archive. Retrieved 10 October 2018.
- ^ a b c d Veillet, C.; Doressoundiram, A.; Shapiro, J.; Kavelaars, J. J.; Morbidelli, A. (April 2001). "S/2000 (1998 WW_31) 1". IAU Circ. 7610 (7610): 1. Bibcode:2001IAUC.7610....1V. Retrieved 10 October 2018.
- ^ a b c d e f g "LCDB Data for (1998 WW31)". Asteroid Lightcurve Database (LCDB). Retrieved 10 October 2018.
- ^ a b Grundy, W.M.; Noll, K.S.; Roe, H.G.; Buie, M.W.; Porter, S.B.; Parker, A.H.; Nesvorný, D.; Levison, H.F.; Benecchi, S.D.; Stephens, D.C.; Trujillo, C.A. (December 2019). "Mutual orbit orientations of transneptunian binaries". Icarus. 334: 62–78. doi:10.1016/j.icarus.2019.03.035.
- ^ a b c d e Brown, Michael E. "How many dwarf planets are there in the outer solar system?". California Institute of Technology. Retrieved 10 October 2018.
- ^ a b Hainaut, O. R.; Boehnhardt, H.; Protopapa, S. (October 2012). "Colours of minor bodies in the outer solar system. II. A statistical analysis revisited". Astronomy and Astrophysics. 546: 20. arXiv:1209.1896. Bibcode:2012A&A...546A.115H. doi:10.1051/0004-6361/201219566. S2CID 54776793.
- ^ a b c "Asteroid 1998 WW31". Small Bodies Data Ferret. Retrieved 10 October 2018.
- ^ Fornasier, S.; Dotto, E.; Hainaut, O.; Marzari, F.; Boehnhardt, H.; De Luise, F.; et al. (October 2007). "Visible spectroscopic and photometric survey of Jupiter Trojans: Final results on dynamical families". Icarus. 190 (2): 622–642. arXiv:0704.0350. Bibcode:2007Icar..190..622F. doi:10.1016/j.icarus.2007.03.033. S2CID 12844258.
External links
edit- The binary Kuiper-belt object 1998 WW31, publication in Nature, 18 April 2002
- The binary Kuiper Belt Object 1998 WW31, Christian Veillet - CFHT - 17 April 2002
- IAUC 7610: S/2000 (1998 WW_31) 1, satellite discovery – Central Bureau for Astronomical Telegrams, 16 April 2001
- Orbit Fit and Astrometric record for 1998 WW31, Marc W. Buie, SwRI (Space Science Department)
- 1998 WW31 and S/2000 (1998 WW31) 1
- MPEC 2008-O05 : Distant Minor Planets (2008 AUG. 2.0 TT)
- 1998 WW31 at AstDyS-2, Asteroids—Dynamic Site
- 1998 WW31 at the JPL Small-Body Database