When was the moon of Makemake officially announced?
The Minor Planet Center officially announced the finding on the 26th of April 2016. This announcement confirmed that Makemake is not alone in its distant journey.
Questions about S/2015 (136472) 1
Short answers, pulled from the story.
How does S/2015 (136472) 1 compare to Makemake in brightness?
S/2015 (136472) 1 measures 1,300 times dimmer than the parent dwarf planet Makemake. The difference in brightness between the two bodies reaches 7.80 magnitudes.
What is the orbital period of S/2015 (136472) 1 around Makemake?
S/2015 (136472) 1 completes one full orbit every 18 days. It follows a likely circular path around its primary body.
Why did earlier telescope observations fail to detect S/2015 (136472) 1?
Earlier telescope observations failed because the orbital plane appears edge-on from Earth-based observatories. This orientation means the satellite passes directly in front of or behind Makemake during certain times and disappears into the glare of the larger dwarf planet most of the time.
What explains the low albedo of S/2015 (136472) 1?
The extreme darkness results from gravity that is too weak to hold onto bright volatile ices. As these ices sublimate off the surface, they escape into space rather than staying attached, leaving behind a dark exterior layer similar to charcoal.