1421 Esperanto, provisional designation , is a dark background
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
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from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 18 March 1936, by Finnish astronomer Yrjö Väisälä at the
Iso-Heikkilä Observatory
Iso-Heikkilä Observatory ( fi, Iso-Heikkilän tähtitorni, sv, Storheikkilä observatorium) is an amateur astronomical observatory used by a local amateur astronomical association, Turun Ursa ry in the Iso-Heikkilä district of Turku, Finl ...
in Turku, southwest Finland. The presumed C-type asteroid has a
rotation period
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...
of nearly 22 hours. It was named for the artificial language
Esperanto
Esperanto ( or ) is the world's most widely spoken constructed international auxiliary language. Created by the Warsaw-based ophthalmologist L. L. Zamenhof in 1887, it was intended to be a universal second language for international communi ...
.
Orbit and classification
''Esperanto'' has been determined a non-
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
asteroid from the main belt's background population by means of modern HCM-analysis, after it had previously been grouped to the
Eos family The Eos family (''adj. Eoan'' ; ) is a very large asteroid family located in the outer region of the asteroid belt. The family of K-type asteroids is believed to have formed as a result of an ancient catastrophic collision. The family's parent body ...