88 Thisbe

On 7 October 1981, asteroid 88 Thisbe was observed to occult the 9th-magnitude star SAO 187124 from 12 sites. The timing of the different chords across the asteroid provided a diameter estimate of 232±12 km. This is 10% larger than the diameter estimate based on radiometric techniques. During 2000, 88 Thisbe was observed by radar from the Arecibo Observatory. The return signal matched an effective diameter of 207 ± 22 km. This is consistent with the asteroid dimensions computed through other means.

Photometric observations of this asteroid during 1977 gave a light curve with a period of 6.0422 ± 0.006 hours and a brightness variation of 0.19 in magnitude.

Perturbation

Asteroid 7 Iris has perturbed Thisbe; in 2001, Michalak estimated it to have a mass of 15×10¹⁸ kg. But Iris is strongly perturbed by many minor planets such as 10 Hygiea and 15 Eunomia.

In 2008, Baer estimated Thisbe to have a mass of 10.5×10¹⁸ kg. In 2011, Baer revised this to 18.3×10¹⁸ kg with an uncertainty of 1.1×10¹⁸ kg.