Hestia has been studied by radar. 13-cm radar observations of this asteroid from the Arecibo Observatory between 1980 and 1985 were used to produce a diameter estimate of 131 km. In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.
In 2000, Michalak estimated Hestia to have a mass of 3.5×1018 kg.
Even though Hestia is only about 124 km in diameter, in 1997, Bange and Bec-Borsenberger estimated Hestia as having a mass of 2.1×1019 kg, based on a perturbation by 19 Fortuna. This older 1997 estimate would give it a density of 14+ g/cm³ and make Hestia more massive than several much larger asteroids.
^ abPilcher, Frederick (July 2012), "Rotation Period Determinations for 46 Hestia, 223 Rosa, 225 Henrietta, 266 Aline, 750 Oskar, and 765 Mattiaca", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers39 (3): 171–173, Bibcode:2012MPBu...39..171P.
^Šidlichovský, M. (1999), "Resonances and chaos in the asteroid belt", in Svoren, J.; Pittich, E. M.; Rickman, H., Evolution and source regions of asteroids and comets : proceedings of the 173rd colloquium of the International Astronomical Union, held in Tatranska Lomnica, Slovak Republic, August 24–28, 1998: 297–308, Bibcode:1999esra.conf..297S.
^Gradie, J.; Flynn, L. (March 1988), "A Search for Satellites and Dust Belts Around Asteroids: Negative Results", Abstracts of the Lunar and Planetary Science Conference19: 405–406, Bibcode:1988LPI....19..405G.
^(2000 mass estimate of 46 Hestia 0.018 / Mass of Ceres 4.75) * Mass of Ceres 9.43E+20 = 3.573E+18