189 Phthia
Encyclopedia
189 Phthia
Orbital characteristics [ftp://ftp.lowell.edu/pub/elgb/astorb.html 1]
Orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

 type
Main belt
Asteroid belt
The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...

Semimajor axis  2.450 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

Perihelion distance 2.360 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

Aphelion distance 2.541 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

Orbital period
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...

 
3.84 years
Inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...

 
5.18°
Eccentricity  0.037
Physical characteristics [ftp://ftp.lowell.edu/pub/elgb/astorb.html 1]
Diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

 
37.7 km
Rotation period
Rotation period
The rotation period of an astronomical object is the time it takes to complete one revolution around its axis of rotation relative to the background stars...

 
15 hours
Spectral class  S
S-type asteroid
S-type asteroids are of a stony composition, hence the name. Approximately 17% of asteroids are of this type, making it the second most common after the C-type.-Characteristics:...

Abs. magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...

 
9.33
Albedo
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...

 4
0.231
History 2
Discoverer C. H. F. Peters
Christian Heinrich Friedrich Peters
Christian Heinrich Friedrich Peters was a German-American astronomer, and one of the first to discover asteroids....

, 1878


189 Phthia is a bright-coloured, rocky main belt
Asteroid belt
The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...

 asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

.

It was discovered by C. H. F. Peters
Christian Heinrich Friedrich Peters
Christian Heinrich Friedrich Peters was a German-American astronomer, and one of the first to discover asteroids....

 on September 9, 1878 in Clinton, New York
Clinton, Oneida County, New York
Clinton is a village in Oneida County, New York, United States. The population was 1,952 at the 2000 census. It was named for George Clinton, a royal governor of the colony of New York....

 and named after Phthia
Phthia
Phthia , Phthíē ) in ancient Greece was the southernmost region of ancient Thessaly, on both sides of Othrys Mountain. It was the homeland of the Myrmidones tribe, who took part in the Trojan War under Achilles....

, a region of Ancient Greece
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

.
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