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Pluto (: New Horizons

Pluto is a dwarf planet in the Kuiper belt that was the first Kuiper belt object discovered. It has a moderately eccentric orbit between 30-49 AU from the sun and is made primarily of ice and rock. Pluto was originally considered the ninth planet but was reclassified as a dwarf planet in 2006 after the discovery of Eris led the IAU to formally define "planet" and exclude Pluto. Pluto has five known moons, the largest being Charon which is over half of Pluto's diameter. In 2015, the New Horizons spacecraft performed the first flyby of Pluto and made detailed observations.

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48 views1 page

Pluto (: New Horizons

Pluto is a dwarf planet in the Kuiper belt that was the first Kuiper belt object discovered. It has a moderately eccentric orbit between 30-49 AU from the sun and is made primarily of ice and rock. Pluto was originally considered the ninth planet but was reclassified as a dwarf planet in 2006 after the discovery of Eris led the IAU to formally define "planet" and exclude Pluto. Pluto has five known moons, the largest being Charon which is over half of Pluto's diameter. In 2015, the New Horizons spacecraft performed the first flyby of Pluto and made detailed observations.

Uploaded by

Laura Miftode
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of

bodies beyond Neptune. It was the first Kuiper belt object to be discovered. It is the largest and
second-most-massive known dwarf planet in the Solar System and the ninth-largest and tenthmost-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian
object by volume but is less massive than Eris, a dwarf planet in the scattered disc. Like other
Kuiper belt objects, Pluto is primarily made of ice and rock[13] and is relatively smallabout
one-sixth the mass of the Moon and one-third its volume. It has a moderately eccentric and
inclined orbit during which it ranges from 30 to 49 astronomical units or AU (4.47.4 billion km)
from the Sun. This means that Pluto periodically comes closer to the Sun than Neptune, but a
stable orbital resonance with Neptune prevents them from colliding. Light from the Sun takes
about 5.5 hours to reach Pluto at its average distance (39.5 AU).
Pluto was discovered by Clyde Tombaugh in 1930, and was originally considered the ninth
planet from the Sun. After 1992, its planethood was questioned following the discovery of
several objects of similar size in the Kuiper belt. In 2005, Eris, which is 27% more massive than
Pluto, was discovered, which led the International Astronomical Union (IAU) to define the term
"planet" formally for the first time the following year.[14] This definition excluded Pluto and
reclassified it as a member of the new "dwarf planet" category.[15]
Pluto has five known moons: Charon (the largest, with a diameter just over half that of Pluto),
Styx, Nix, Kerberos, and Hydra.[16] Pluto and Charon are sometimes considered a binary system
because the barycenter of their orbits does not lie within either body.[17] The IAU has not
formalized a definition for binary dwarf planets, and Charon is officially classified as a moon of
Pluto.[18]
On July 14, 2015, the New Horizons spacecraft became the first spacecraft to fly by Pluto.[19][20][21]
During its brief flyby, New Horizons made detailed measurements and observations of Pluto and
its moons.[22][23][24]

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