A new model for a cool DQ white dwarf star was developed by analyzing its temperature and carbon abundance using data from different sources. The star GSC2U J131147.2+292348 is the coolest DQ star ever observed, with an estimated temperature of around 5120 K and a low carbon abundance. This challenges previous ideas about the temperature range where DQ stars can exist, suggesting that the transition from certain carbon molecules may not be as straightforward as previously thought.