Julia (
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 ...
: 89 Julia) is a large
main-belt
The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...
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.
...
that was discovered by French astronomer
Édouard Stephan
Édouard Jean-Marie Stephan (31 August 1837 – 31 December 1923) was a French astronomer. His surname is sometimes spelled Stéphan in some literature, but this is apparently erroneous.
He was born in Sainte Pezenne (today one of the districts ...
on August 6, 1866. This was first of his two asteroid discoveries; the other was
91 Aegina. 89 Julia is believed to be named after Saint
Julia of Corsica
Saint Julia of Corsica ( it, Santa Giulia da Corsica; french: Sainte Julie; co, Santa Ghjulia; la, Sancta Iulia), also known as Saint Julia of Carthage, and more rarely Saint Julia of Nonza, was a virgin martyr who is venerated as a Christia ...
. A
stellar 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 ...
by Julia was observed on December 20, 1985.
The spectrum of 89 Julia shows the signature of
silicate
In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is al ...
rich minerals with possible indications of an abundant calcic
clinopyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
component. It is classified as 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 ...
. The asteroid has an estimated diameter of .
Photometry Photometry can refer to:
* Photometry (optics), the science of measurement of visible light in terms of its perceived brightness to human vision
* Photometry (astronomy), the measurement of the flux or intensity of an astronomical object's electro ...
from the Oakley Observatory during 2006 produced a
lightcurve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...
that indicated a
sidereal rotation period
Sidereal time (as a unit also sidereal day or sidereal rotation period) (sidereal ) is a timekeeping system that astronomers use to locate celestial objects. Using sidereal time, it is possible to easily point a telescope to the proper coor ...
of with an
amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplit ...
of in magnitude.
[
]
Nonza crater and Julian family
89 Julia is the parent body of the eponymous Julia family of asteroids. Observations of 89 Julia by the VLT's SPHERE instrument identified a 'highly probable' crater 70–80 km in diameter and deep in the southern hemisphere as the only visible possible source of the family. The crater was named Nonza by the discoverers, referring to the commune
A commune is an alternative term for an intentional community. Commune or comună or comune or other derivations may also refer to:
Administrative-territorial entities
* Commune (administrative division), a municipality or township
** Communes of ...
on the island of Corsica where Saint Julia was born.
References
External links
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{{DEFAULTSORT:Julia
000089
Discoveries by Édouard Stephan
Named minor planets
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