Fortuna is 225 km in diameter and has one of the darkest known geometricalbedos for an asteroid over 150 km in diameter. Its albedo has been measured at 0.028 and 0.037.[8] The spectra of the asteroid displays evidence of aqueous alteration.[9]
It was discovered byJ. R. Hind on 22 August 1852, and named afterFortuna, theRoman goddess ofluck. Its historical symbol was a star over Fortune's wheel; it was encoded inUnicode 17.0 as U+1CECC ().[10][11]
TheHubble Space Telescope observed Fortuna in 1993. It was resolved with an apparent diameter of 0.20arcseconds (4.5pixels in the Planetary Camera) and its shape was found to be nearly spherical.Satellites were searched for but none were detected.
Fortuna has beenperturbed by the 80 km135 Hertha and was initially estimated by Baer to have a mass of 1.08×1019 kg.[6] A more recent estimate by Baer suggests it has a mass of 1.27×1019 kg.[3]
On 21 December 2012, Fortuna (~200 km) harmlessly passed within 6.5 Gm of asteroid687 Tinette.[13]
^abcdefghijkP. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis.Astronomy & Astrophysics 54, A56
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