We report the results of two multi-chord stellar occultations by the dwarf planet ( 1 ) Ceres that were observed from Brazil on 2010 August 17 , and from the USA on 2013 October 25 .
Four positive detections were obtained for the 2010 occultation , and nine for the 2013 occultation .
Elliptical models were adjusted to the observed chords to obtain Ceres ’ size and shape .
Two limb fitting solutions were studied for each event .
The first one is a nominal solution with an indeterminate polar aspect angle .
The second one was constrained by the pole coordinates as given by Drummond et al .
Assuming a Maclaurin spheroid , we determine an equatorial diameter of 972 \pm 6 km and an apparent oblateness of 0.08 \pm 0.03 as our best solution .
These results are compared to all available size and shape determinations for Ceres made so far , and shall be confirmed by the NASA ’ s Dawn space mission .