The 112th asteroid to be discovered was named Iphigenia by the astronomer who spotted it, and is fairly average in almost every respect. Located between the orbits of Mars and Jupiter, Iphigenia is one of the millions of irregularly shaped objects that make up the asteroid belt. Due to the gravitational influence of Jupiter, Iphigenia and all of its neighboring asteroids were not able to accrete into a planet in the solar nebula. Iphigenia was discovered during a period that many asteroids were being found and it was given a generic Greek name like many others of the time. Today so many asteroids have been discovered that they are rarely named at all, and simply get labeled with a number.
Asteroid number 112 was discovered by Christian Heinrich Friedrich Peters on September 19th, 1870. Peters was a German-American astronomer who was among the first observers to discover asteroids. Prompted by the Titius-Bode law of planetary distance, astronomers had been searching the area of the solar system between the terrestrial and Jovian planets for about a century in hopes of locating a new planet that fit the scheme. By the time Peters noticed Iphigenia, the discovery of Neptune had discredited Bode's law. Even so, astronomers expected to uncover more celestial objects in the region and they were not disappointed. Peters located 47 other asteroids besides Iphigenia, making him one of the more prolific discoverers of asteroids.
The size of Iphigenia is somewhat large compared to the majority of known asteroids. Its mass is 3.9x1017 kilograms and it has a diameter of 72.2 kilometers (about 0.045 arcseconds). Most asteroids are no more than 100 kilometers in diameter with the bulk of them being far smaller, so number 112 is by no means tiny on the scale of asteroid sizes. Iphigenia is very dark, with an albedo of 0.039. It is believed by observers to be primarily composed of primitive carbonaceous material. The mean temperature of Iphigenia is around 178 Kelvin, which is closer to the cloudtop temperature of Jupiter than the mean temperature of Mars.
Asteroid 112 Iphigenia is considered a C-type asteroid based on spectral analysis. This puts it in the most broad spectral category of asteroids, since 75% of all discovered asteroids have a C-type spectral signature. The remainder of asteroids that are not carbonaceous are either silicate or metal-rich in composition. Iphigenia has strong ultraviolet absorption at wavelengths between 0.4 micrometers and 0.5 micrometers. Spectral analysis indicates the possibility of water content on the asteroid.
The orbital properties of Iphigenia are comparable to most of the objects in the asteroid belt. Its aphelion is roughly 2.745 astronomical units and its perihelion is about 2.122 astronomical units. Since the perihelion is less than 1.3 astronomical units, asteroid 112 is not considered a near-Earth object and poses no threat of collision. Some asteroids, such as 4179 Toutatis, have been deemed potentially dangerous because of their size and proximity to Earth. The orbital period of Iphigenia is 1386.548 days, which is shorter than many other asteroids whose orbital period can be as great as six years. Iphigenia has an orbital eccentricity of 0.128 and its speed is approximately 19.01 kilometers per second. Its distance from Earth is 2.202 astronomical units.
Lightcurve photometry of 112 Iphigenia was obtained for six days in December of 2007. The resulting graph from data gathered between December 9-14 indicated a synodic rotation period of 31.385 ± 0.006 hours and lightcurve amplitude of 0.30 ± 0.02 magnitude. This observation was conducted at the Observatorio Astronomico de Mallorca in Spain, which uses robotic telescopes to locate and track asteroids.
Very recently, Iphigenia occulted a star in the constellation Sagittarius for observers in Australia. On November 5th 2010, it passed in front of star 2UCAC 23508986 at approximately 9:41pm (UT time). The magnitude of the occulted star is 12, or about the brightness of the Sun as seen from Rigel. During the 2.6 seconds of occultation, the combined light of the asteroid and the star dropped by 2.5 to 14.4 mag (the magnitude of 112 Iphigenia). At the time of this writing, no new data had been posted from observations of this occultation.