Briefly write down characteristics of Plato. Do you think that Pluto is still ninth planet of our solar system?

Characteristics of Pluto:

• Pluto's mass is 1.31×1022 kg, less than 0.24% that of the Earth, while its diameter is 2,306 (+/- 20) km, or roughly 66% that of the Moon..
• Its surface pressure ranges from 6.5 to 24 μbar.
• Its mean radius is 1153 ± 10 km..
• Its Surface area is 1.665 ×107 Sq.km.
• Pluto is thought to be a residual planetesimal; a component of the original proto-planetary disc around the Sun that failed to fully coalesce into a full-fledged planet. Most astronomers agree that Pluto owes its current position to a sudden migration undergone by Neptune early in the Solar System's formation.
  
• Pluto has a density of about two times that of water (2.03 ± 0.06 g/cm3) and it is estimated that Pluto may have a core of silicate rock about 1700 km in diameter, which is surrounded by ices of water, methane, and carbon monoxide. The crust of Pluto may be a thin coating of nitrogen, methane, and carbon monoxide ice.
• It has an eccentric orbit and highly inclined with respect to the ecliptic, that it crosses approaching in its perihelion until the interior of the orbit of Neptune hence has been classified like dwarf since it is in the Belt of Kuiper.
• Pluto's elongated orbit is predicted to have a major effect on its atmosphere: as Pluto moves away from the Sun, its atmosphere should gradually freeze out, and fall to the ground. When Pluto is closer to the Sun, the temperature of Pluto's solid surface increases, causing the ices to sublimate into gas. This creates ananti-greenhouse effect. Scientists using the Submillimeter Array have recently discovered that Pluto's average temperature is about 43 Kelvin (−230 °C).
• Pluto has four known natural satellites: Charon was the first identified in 1978 by astronomer James Christy; Nix and Hydra, both discovered in 2005, and S/2011 P 1 (provisional name, also known as P4), identified by the Hubble Space Telescope in 2011. Charon is the greater one with a diameter of /3 of Pluto.

Pluto is no more considered as Planet:

Pluto was discovered On February 18, 1930 by American astronomer Clyde William Tombaugh (1906-1997) from the Lowell Observatory in Flagstaff, Arizona. Pluto was considered a planet for only 75 years, and questions about its planetary status had been raised for more than 10 years.
Pluto is no more considered as Planet owing to the resolution passed by the International Astronomical Union (IAU) on 24 August 2006; it determines the basic criteria for planet in our solar system in the following way:
A “planet” is a celestial body that:
(a) is in orbit around the Sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
(c) has cleared the neighbourhood around its orbit.
Pluto in this regard fails to fulfil the third criteria, as Pluto has many friends orbiting nearby, which is not the case for any of the planets. The planets accumulate, eject, or otherwise control all the mass in their immediate proximity. Pluto and Ceres are not able to do that; therefore they belong to a class i.e. dwarf planet that is really quite distinct from the eight planets. Its mass is only 0.07 times that of the mass of the other objects in its orbit (Earth's mass is comparatively 1.7 million times the remaining mass in its own orbit).