The Trans-Neptunian Object (84922) 2003 VS2 through Stellar Occultations

We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the plutino object (84922) 2003 VS2. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on 2014 November 7, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotational light curve present a peak-to-peak amplitude of 0.141 0.009 mag. This allows us to reconstruct the 3D shape of the body, with principal semi-axes of a = 313.8 7.1 km, km, and km, which is not consistent with a Jacobi triaxial equilibrium figure. The derived spherical volume equivalent diameter of km is about 5% larger than the radiometric diameter of 2003 VS2 derived from Herschel data of 523 35 km, but still compatible with it within error bars. From those results we can also derive the geometric albedo ( ) and, under the assumption that the object is a Maclaurin spheroid, the density for the plutino. The disappearances and reappearances of the star during the occultations do not show any compelling evidence for a global atmosphere considering a pressure upper limit of about 1 microbar for a pure nitrogen atmosphere, nor secondary features (e.g., rings or satellite) around the main body.