From two observing runs during the 2014 summer at Calar Alto Observatory in Almería ( Spain ) and at Sierra Nevada Observatory in Granada ( Spain ) , we were able to derive CCD photometry of the Trans-Neptunian Object 2008 OG _ { 19 } .
We analyzed the time series and obtained a double-peaked light curve with a peak to valley amplitude of ( 0.437 \pm 0.011 ) mag and a rotational period of ( 8.727 \pm 0.003 ) h. This implies that this object is very elongated , closely resembling Varuna ’ s case .
The photometry also allowed us to obtain an absolute magnitude in R-band of ( 4.39 \pm 0.07 ) mag .
From this result we estimated an equivalent diameter of 2008 OG _ { 19 } which is 619 ^ { +56 } _ { -113 } km using an average albedo for Scattered Disk Objects .
Finally we interpreted the results under the assumption of hydrostatic equilibrium and found a lower limit for the density of 544 ^ { +42 } _ { -4 } kg m ^ { -3 } .
However , a more likely density is 609 \pm 4 kg m ^ { -3 } using an aspect angle of 60 ^ { \circ } , which corresponds to the most likely configuration for the spin axis with respect to the observer assuming random orientations .