  On 28th January 2018, the large Trans-Neptunian Object (TNO) 2002TC302
occulted a m$_v= $15.3 star with ID 130957813463146112 in the Gaia DR2 stellar
catalog. 12 positive occultation chords were obtained from Italy, France,
Slovenia and Switzerland. Also, 4 negative detections were obtained near the
north and south limbs. This represents the best observed stellar occultation by
a TNO other than Pluto, in terms of the number of chords published thus far.
From the 12 chords, an accurate elliptical fit to the instantaneous projection
of the body, compatible with the near misses, can be obtained. The resulting
ellipse has major and minor axes of 543 $\pm$ 18 km and 460 $\pm$ 11 km,
respectively, with a position angle of 3 $\pm$ 1 degrees for the minor axis.
This information, combined with rotational light curves obtained with the 1.5m
telescope at Sierra Nevada Observatory and the 1.23m telescope at Calar Alto
observatory, allows us to derive possible 3D shapes and density estimations for
the body, based on hydrostatic equilibrium assumptions. The effective area
equivalent diameter is $\sim$ 84 km smaller than the radiometrically derived
diameter using thermal data from Herschel and Spitzer Space Telescopes. This
might indicate the existence of an unresolved satellite of up to $\sim$ 300 km
in diameter, to account for all the thermal flux, although the occultation and
thermal diameters are compatible within their error bars given the considerable
uncertainty of the thermal results. The existence of a potential satellite also
appears to be consistent with other ground-based data presented here. From the
effective occultation diameter combined with H$_V$ measurements we derive a
geometric albedo of 0.147 $\pm$ 0.005, which would be somewhat smaller if
2002TC302 has a satellite. The best occultation light curves do not show any
signs of ring features or any signatures of a global atmosphere.
