1148 Rarahu
1148 Rarahu, provisional designation and previously also known as, is an Eoan asteroid from the outer regions of the asteroid belt, approximately 32 kilometers in diameter. Discovered by Alexander Deutsch at the Simeiz Observatory in 1929, the asteroid's name was taken from a French novel by Pierre Loti.
Discovery
Rarahu was discovered on 5 July 1929, by Soviet astronomer Alexander Deutsch at the Simeiz Observatory on the Crimean peninsula. On July 28, it was independently discovered by Cyril Jackson and Harry Wood at Johannesburg Observatory in South Africa. The Minor Planet Center only recognizes the first discoverer.Orbit and classification
Rarahu is a member the Eos family, the largest asteroid family of the outer main belt, named after its parent body, the asteroid 221 Eos. The family consists of nearly 10,000 asteroids.It orbits the Sun at a distance of 2.7–3.3 AU once every 5 years and 3 months. Its orbit has an eccentricity of 0.11 and an inclination of 11° with respect to the ecliptic. The asteroid was first observed as at Simeiz Observatory in July 1924. The body's observation arc begins at Johannesburg in July 1929, one week after its official discovery observation at Simeiz.
Physical characteristics
In the Tholen classification, Rarahu is a stony S-type asteroid. In the SMASS classification it is a K-type asteroid, which is a refined spectral type to which most members of the Eos family, including the parent body, belong to.Rotation period
Between 2002 and 2011, three rotational lightcurves of Rarahu were obtained from photometric observations by French amateur astronomers René Roy, Laurent Brunetto and Pierre Antonini. Lightcurve analysis gave a consolidated rotation period of 6.5447 hours with a brightness amplitude between 0.05 and 0.94 magnitude.Spin axis
The asteroid's lightcurve has also been modeled several times and gave a concurring period of 6.54448 and 6.54449 hours, respectively. The body's spin axis has also been determined to be at and in ecliptic coordinates.Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Rarahu measures between 26.311 and 49.11 kilometers in diameter and its surface has an albedo between 0.064 and 0.2205.The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.1393 and a diameter of 33.23 kilometers based on an absolute magnitude of 10.15.