Iowa Great Lakes Astronomical Society

Makemake: The Easter Dwarf

From East Egg to Easterbunny to God to Dwarf

by Adam Dietrick

On March 31, 2005, a team lead by Caltech's Mike Brown found a four-day late Easter egg in the Kuiper belt. At roughly 1/5th the brightness and ¾ the size of well known Pluto, the object initially labeled 2005FY9 is the only known trans-neptunian object (TNO) that could have been detected by Pluto discoverer Clyde Tombaugh during his 1930 search for TNOs. However, at the time it was very near the Milky Way, which made it virtually undetectable with the equipment at Tombaugh's disposal.

It was not until more than three years later that the object was finally christened.

“Three years is a long time to have only a license plate number instead of a name,” Brown stated in his blog. “So for most of the time, we simply referred to this object as “Easterbunny” in honor of the fact that it was discovered just a few days past Easter in 2005.”

Image of Makemake

After several failed attempts at coming up with a fitting name for the object and rumors that the IAU would name the object themselves, Brown had an epiphany that led to him naming his discovery after the Rapa Nui (Easter Island) creator and fertility god Makemake.

“I am partial to fertility gods for things I discovered around that time.” writes Brown. “Eris, Makemake, and 2003 EL61 were all discovered as my wife was three to six months pregnant with our daughter.” Even though Brown had succeeded at finally naming his discovery, it was not an easy adjustment for the astronomer. “If you came in tomorrow and told me that from now on my daughter – who also just turned three – was to suddenly be called something new, I would have a hard time with that, too.”

Makemake is the third largest of the dwarf planets, smaller than both Eris and Pluto. It's surface is coated in red methane and it likely has a transient atmosphere composed primarily of methane and nitrogen. It is a classical Kuiper belt object and not a plutino, the difference being that plutinos have a 2:3 resonance with Neptune and actually spend some of their orbital year within the orbit of the big blue gas giant. Classical Kuiper belt objects typically have low orbital eccentricities, but Makemake has a highly inclined orbit when compared to others in it's class. Also peculiar for the class is that no satellites have been detected orbiting Makemake, which makes it unique among the large TNOs of which we are aware.

When Makemake's discovery was announced on July, 29, 2005, it was largely ignored as this was the very same day that Brown's team announced an even more distant and massive object, now known as Eris. In response this overshadowing, Brown told me that, “Poor Makemake remains the ignored stepchild of the outer solar system. I'm trying to slowly fix that!”

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