Peitho (
minor planet designation
A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...
: 118 Peitho) is a
main-belt 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.
...
. It is probably an
S-type asteroid
S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second ...
, suggesting a
siliceous mineralogy. It was discovered by
R. Luther on March 15, 1872, and named after one of the two
Peithos in
Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
. There have been two observed Peithoan
occultation
An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...
s of a dim
star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
: one was in 2000 and the other in 2003.
This body is orbiting the
Sun with a
period of 3.81 years and an
eccentricity (ovalness) of 0.16. The
orbital plane is
inclined
Incline, inclined, inclining, or inclination may refer to:
*Grade (slope), the tilt, steepness, or angle from horizontal of a topographic feature (hillside, meadow, etc.) or constructed element (road, railway, field, etc.)
*Slope, the tilt, steepn ...
by 7.7° to the
plane of the ecliptic. The cross-section diameter is ~42 km. In 2009,
Photometric observations of this asteroid were made at the Palmer Divide Observatory in
Colorado Springs, Colorado
Colorado Springs is a home rule municipality in, and the county seat of, El Paso County, Colorado, United States. It is the largest city in El Paso County, with a population of 478,961 at the 2020 United States Census, a 15.02% increase since ...
. The resulting asymmetrical
light curve shows a synodic
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 7.823 ± 0.002 hours with a brightness variation of 0.15 ± 0.02 in
magnitude. This was reasonably consistent with independent studies performed in 1980 (7.78 hours) and 2009 (7.8033 hours).
The
lightcurve inversion process has been used to construct a model of this object,
[ suggesting a blocky shape with flattened poles.
]
References
External links
Lightcurve plot of 118 Peitho
Palmer Divide Observatory, '' B. D. Warner'' (2009)
Asteroid Lightcurve Database (LCDB)
query form
)
Dictionary of Minor Planet Names
Google books
– Observatoire de Genève, Raoul Behrend
– Minor Planet Center
*
*
000118
Discoveries by Robert Luther
Named minor planets
000118
000118
000118
18720315
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