Proteus (muin)

Frae Wikipedia
Jump to navigation Jump to search
Proteus
Proteus (Voyager 2).jpg
Voyager 2 eemage (1989)
Discovery
Discovered biVoyager 2
Stephen P. Synnott
Discovery date16 Juin 1989
Designations
AdjectivesProtean
Orbital chairactereestics[1]
Epoch 18 August 1989
Periapsis117584±10 km
Apoapsis117709±10 km
117647±1 km (4.75 RN)
Eccentricity0.00053±0.00009
1.12231477±0.00000002 d
7.623 km/s
Inclination0.524° (to Neptune equator)
0.026°±0.007° (tae local Laplace plane)
Satellite oNeptune
Pheesical chairacteristics
Dimensions424 × 390 × 396 km[2][lower-alpha 1]
Mean radius
210±7 km[5]
Vollum(3.4±0.4)×107 km3[2]
Mass4.4×1019 kg (7.3672×10−6 Earths)[lower-alpha 2]
Mean density
≈ 1.3 g/cm³ (estimate)[5]
0.07 m/s2[lower-alpha 3]
0.17 km/s[lower-alpha 4]
synchronous[2]
zero[2]
Albedo0.096[5][6]
Temperatur≈ 51 K mean (estimate)
19.7[5]

Proteus (Greek: Πρωτεύς), an aw kent as Neptune VIII, is the seicont-lairgest Neptunian muin, and Neptune's largest inner satellite.

Notes[eedit | eedit soorce]

  1. In the earlier papers slichtly different dimensions war reportit. Thomas an Veverka in 1991 reportit 440×416×404 km.[2][3] Croft in 1992 reportit 430×424×410 km.[4] The difference is caused bi the uise o different sets o eemages an bi the fact that the shape o Proteus is nae descrived well bi a triaxial ellipsoid.[2]
  2. The mass wis calculated bi multiplyin the vollum frae Stooke (1994)[2] bi the assumed density o 1,300 kg/m3. If ane uises slichtly lairger dimensions frae the earlier papers the mass will increase tae 5×1019 kg.[5]
  3. Surface gravity derived frae the mass m, the gravitational constant G an the radius r: Gm/r2.
  4. Escape velocity derived frae the mass m, the gravitational constant G an the radius r: 2Gm/r.

References[eedit | eedit soorce]

  1. Jacobson, R. A.; Owen, W. M., Jr. (2004). "The orbits of the inner Neptunian satellites from Voyager, Earthbased, and Hubble Space Telescope observations". Astronomical Journal. 128 (3): 1412–1417. Bibcode:2004AJ....128.1412J. doi:10.1086/423037. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Stooke, Philip J. (1994). "The surfaces of Larissa and Proteus". Earth, Moon, and Planets. 65 (1): 31–54. Bibcode:1994EM&P...65...31S. doi:10.1007/BF00572198. 
  3. Williams, Dr. David R. (2008-01-22). "Neptunian Satellite Fact Sheet". NASA (National Space Science Data Center). Retrieved 2008-12-12. 
  4. Croft, S. (1992). "Proteus: Geology, shape, and catastrophic destruction". Icarus. 99 (2): 402–408. Bibcode:1992Icar...99..402C. doi:10.1016/0019-1035(92)90156-2. 
  5. 5.0 5.1 5.2 5.3 5.4 "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 2010-10-18. Retrieved 2011-10-11. 
  6. Karkoschka, Erich (2003). "Sizes, shapes, and albedos of the inner satellites of Neptune". Icarus. 162 (2): 400–407. Bibcode:2003Icar..162..400K. doi:10.1016/S0019-1035(03)00002-2.