4175 Billbaum

It was discovered on 15 April 1985, by American astronomer Edward Bowell at the Anderson Mesa Station of the Lowell Observatory near Flagstaff, Arizona.

[1][4] Billbaum is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.

[8][4] In January and February 2011, three rotational lightcurves of Billbaum were obtained from photometric observations by Ralph Megna, Josep Aymami and astronomers at the Oakley Southern Sky Observatory.

[4] According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Billbaum measures 8.87 kilometers in diameter and its surface has an albedo of 0.27,[5] while the Collaborative Asteroid Lightcurve Link assumes a stony standard albedo of 0.21, derived from 15 Eunomia, the Eunomia family's parent body – and calculates a diameter of 9.60 kilometers based on an absolute magnitude of 12.4.

[4] This minor planet was named after American astronomer William A. Baum (1924–2012) who was on the directorship of the Lowell Observatory's Planetary Research Center.