The spectrum of 89 Julia shows the signature of silicate rich minerals with possible indications of an abundant calcic clinopyroxene component. It is classified as an S-type asteroid. The asteroid has an estimated diameter of 151.4±3.1 km.[8]Photometry from the Oakley Observatory during 2006 produced a lightcurve that indicated a sidereal rotation periodof11.38±0.01 with an amplitudeof0.20±0.02 in magnitude.[9]
89 Julia is the parent body of the eponymous Julia family of asteroids. Observations of 89 Julia by the VLT's SPHERE instrument identified a 'highly probable' crater 70–80 km in diameter and 4.1±1.7 km deep in the southern hemisphere as the only visible possible source of the family.[10] The crater was named Nonza by the discoverers, referring to the commune on the island of Corsica where Saint Julia was born.[11] The excavated volume is on the order of 5,000 to 15000km3. It is hypothesized an impact 30 to 120 million years ago by another body approximately 8 kilometers in diameter may have created the collisional family.
^ abcdeP. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
^ abcdeVernazza et al. (August 2018) The impact crater at the origin of the Julia family detected with VLT/SPHERE?, Astronomy and Astrophysics 618, DOI: 10.1051/0004-6361/201833477
