Physical characterization of the active asteroid (6478) Gault

We report dense lightcurve photometry, $BVR_{c}$ colors and phase - mag curve of (6478) Gault, an active asteroid with sporadic comet-like ejection dust. collected optical observations along the 2020 Jul-Nov months during which appear always star-like, without any form perceptible activity. found complex lightcurves, low amplitude around opposition a bit higher far opposition, mean best rotation period $2.46_{\pm 0.02}$ h. Shape changes were observed in phased lightcurves after probable indication concavities surface irregularities. suspect existence Amplitude-Phase Relationship $C$ band. The are $B-V = +0.84_{\pm 0.04}$, $V-R_{c} +0.43_{\pm 0.03}$ $B-R_{c} +1.27_{\pm 0.02}$, compatible S-type asteroid, but variables rotational index non-homogeneous composition. From our Shevchenko's empirical photometric system, geometric albedo result $p_V=0.13_{\pm lower than average value S-class. estimate absolute $V$ band about +14.9 this, together value, allows to diameter 3-4 km, so Gault may be smaller previously thought.