2MASS colour-colour diagram. The red, green, and blue lines represent the main sequence, supergiant and giant locations, respectively. These were built from the PARSEC evolutionary tracks⁸ with Solar metallicity. The dashed grey lines are 10 mag length reddening vectors. The upward and downward triangles are the classified cool stars (#1, #9, and #30) and the suspected cool ones (#3, #4, and #7), respectively.