Proteus ( dr. Greek Πρωτεύς ), also known as Neptune VIII , is Neptune’s second largest satellite and its largest internal satellite . Proteus is also the largest non-spherical satellite in the solar system . Named after Proteus , a sea deity in ancient Greek mythology .
| Proteus | |
|---|---|
| Neptune's satellite | |
 | |
| Discovery story | |
| Discoverer | Voyager 2 Stephen Sinnot |
| opening date | June 16, 1989 (announced July 7, 1989 ) |
| Orbital characteristics | |
| Semimajor axis | 117 647 km |
| Eccentricity | 0,0004 |
| Circulation period | 1.1223 days |
| Orbital inclination | 0.04 ° (to the plane of the ecliptic ) |
| physical characteristics | |
| Diameter | (radius) 220 × 208 × 202 km |
| Weight | 5⋅10 19 kg |
| Acceleration of gravity | 0.07 m / s2 |
| Albedo | 0.1 |
| Surface temperature | -270 C ° |
| Atmosphere | missing |
Opening
Proteus was discovered in images taken from the Voyager 2 spacecraft during the flight of Neptune in 1989. The satellite was given the provisional designation S / 1989 N 1 .
The discovery of the satellite was announced on July 7, 1989. American scientists Stephen Sinnot and Bradford Smith reported that the satellite “was observed in 17 frames received within 21 days” [2] .
The official name of the satellite was assigned on September 16, 1991 [3] .
Features
The satellite’s dimensions are 440 × 416 × 404 km [4] [5] ; it is larger than Nereida , another satellite of Neptune. However, Proteus was not discovered by ground - based telescopes , since it is close to the planet, which did not allow earth observers to find it behind the brilliance of Neptune [6] .
The surface of Proteus is covered with craters , of which only one has the official name - Faros . This crater is the reference point for coordinates on the satellite. Proteus does not show any signs of possible geological activity [6] . Scientists believe that, given the size of the satellite, over time it can take a spherical shape under the influence of its own gravity [7] . Thus, Saturn’s satellite Mimas has a spherical shape, although, according to estimates [8] , it is inferior to Proteus in mass.
Notes
- ↑ PJ Stooke. The Surfaces of Larissa and Proteus (English) // EARTH, MOON AND PLANETS. - 1994. - Vol. 65 . - P. 31-54 .
- ↑ Stephen P. Synnott, Bradford A. Smith. IAUC 4806: 1989 N 1; Occn OF 28 Sgr BY TITAN; mu Cen; 1987A (1989 N 1) (English) (inaccessible link - history ) . IAU Central Bureau for Astronomical Telegrams.
- ↑ IAUC 5347: SNe; 1991o; Sats OF SATURN AND NEPTUNE (inaccessible link - history ) . IAU Central Bureau for Astronomical Telegrams.
- ↑ Williams, Dr. David R. Neptunian Satellite Fact Sheet . NASA (National Space Science Data Center). Date of treatment January 10, 2010.
- ↑ E. Karkoschka. Sizes, shapes, and albedos of the inner satellites of Neptune (English) // Icarus : journal. - Elsevier , 2003 .-- Vol. 162 . - P. 400 . - DOI : 10.1016 / S0019-1035 (03) 00002-2 .
- ↑ 1 2 Satellite - Proteus (Unavailable link) . Astrolab.Ru. Date of treatment January 10, 2010. Archived February 18, 2012.
- ↑ Michael E. Brown. The Dwarf Planets California Institute of Technology, Department of Geological Sciences. Date of treatment January 10, 2010. Archived on August 17, 2011.
- ↑ Planetary Satellite Physical Parameters . JPL (Solar System Dynamics). Date of treatment January 10, 2010. Archived January 18, 2010.