Asteroid 153 Hilda was discovered on November 2nd, 1875, by Johann Palisa, a man with an eye for an asteroid. He discovered 122 in total, with Hilda being his seventh.
According to the JPL Small-Body Database, Hilda is just over 170km in diameter (105 miles), rotates once every 5.9 hours, takes very nearly eight years to orbit the Sun, and is of Tholen spectral type “P”.
P-type asteroids are few in number. They are very dark, of low density, and tend towards the outer reaches of the main asteroid belt.
153 Hilda now has a whole group of dark asteroids named after her, mostly P- and D-types, occasionally C-types. Numbering more than 5,000, they inhabit an area just beyond the main asteroid belt, but within the orbit of Jupiter.
Hilda was named after Hildegard, the daughter of Theodor von Oppolzer (1841 to 1886), an Austrian astronomer and mathematician, who was himself heavily into asteroids. Here she is perched on a table, with her mother Coelestine and brother Johann.
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