177 Irma
Encyclopedia
| 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 | 2.770 AU Astronomical unit An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance.... |
| Perihelion distance | 2.115 AU Astronomical unit An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance.... |
| Aphelion distance | 3.426 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... |
4.61 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... |
1.39° |
| Eccentricity | 0.237 |
| 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... |
73.22 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... |
14.208 hours |
| Spectral class | C C-type asteroid C-type asteroids are carbonaceous asteroids. They are the most common variety, forming around 75% of known asteroids, and an even higher percentage in the outer part of the asteroid belt beyond 2.7 AU, which is dominated by this asteroid type... |
| 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... |
9.49 |
| 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 |
0.053 |
| History 2 | |
| Discoverer | P. P. Henry, 1877 |
177 Irma is a fairly large and dark 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 brothers Paul Henry and Prosper Henry
Paul Henry and Prosper Henry
Paul-Pierre Henry and his brother Mathieu-Prosper Henry were French opticians and astronomers....
on November 5, 1877. Paul was credited for this discovery.