The discovery of Makemake's little moon increases the parallels between Pluto and Makemake. This is because both of the small icy worlds are already known to be well-coated in a frozen shell of methane. Furthermore, additional observations of the little moon will readily reveal the density of Makemake--an important result that will indicate if the bulk compositions of Pluto and Makemake are similar. "This new discovery opens a new chapter in comparative planetology in the outer Solar System," Dr. Marc Buie commented in the April 26, 2016 Hubble Press Release. Dr. Buie, the team leader, is also of the Southwest Research Institute.
So here you have two definitions of a blue moon but the one for a calendar blue moon does not describe the true meaning of a blue moon. Here's why:
Makemake is a classical KBO. This means that its orbit is situated far enough away from Neptune to remain in a stable stage over the entire age of our more than 4 billion year old Solar System. Classical KBOs have perihelia that carry them far from the Sun, and they are also peacefully free from Neptune's perturbing influence. Such objects show relatively low eccentricities and circle our Star in a way that is similar to that of the major planets. However, Makemake is a member of what is referred to as a "dynamically hot" class of classical KBOs, which instead display a high inclination when compared to other classical KBOs.