A three-dimensional model of 37 Fides based on its light curve
|Discovered by||R. Luther|
|Discovery date||October 5, 1855|
|MPC designation||(37) Fides|
|Epoch December 31, 2006 (JD 2454100.5)|
|Aphelion||464.908 Gm (3.108 AU)|
|Perihelion||325.340 Gm (2.175 AU)|
|395.124 Gm (2.641 AU)|
|1,567.873 d (4.29 a)|
Average orbital speed
|Dimensions||108.35 km ±1.9|
|0.3055 d (7.334 h)|
Fides (// FY-deez; minor planet designation: 37 Fides) is a large main-belt asteroid. It was discovered by German astronomer Karl Theodor Robert Luther on October 5, 1855, and named after Fides, the Roman goddess of loyalty. Fides was the last of the main-belt asteroids to be assigned an iconic symbol. 37 Fides is also a S-type asteroid in the Tholen classification system.
Photometric observations of this asteroid at multiple observatories during 1981–82 gave an unusual light curve with three minima and maxima. The curve changed with varying phase angle of the asteroid relative to the viewer and the position of the Sun, indicating the changing influence of shadows cast by surface features. The composite light curve has a best fit period estimate of 7.33 hours. Austrian astronomer Hans Josef Schober has suggested that the multiple minima and maxima during each period may be an indication of a binary nature.