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Makemake and the Naming of Names

Now that we have vast numbers of Kuiper Belt Objects assumed to be orbiting outside the orbit of Neptune, not to mention possible Oort Cloud interlopers (Sedna may be one of these), the question of names gets ever more interesting. Great entertainment awaits, as witness the KBO known as 2005 FY9. Discovered not long after Easter in 2005, it quickly gained the nickname Easterbunny. It’s now, after several years, been re-christened Makemake, but I like what Mike Brown, who led the discovery team, has to say about this dwarf planet and its earlier monicker:

Three years is a long time to have only a license plate number instead of a name, 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. Three years is such a long time that I think I’m going to have a hard time calling Makemake by its real name. For three years we’ve been tracking it in the sky, observing it with telescopes on the ground and in space, writing proposals to observe it more, writing papers based on what we see, and, all the while, we have just called it – at least amongst ourselves – Easterbunny. 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.

Most parents would, I imagine. Meanwhile, Makemake is itself an interesting name which for some time now has had sanction from the International Astronomical Union. Rapa Nui, also known as Easter Island, is home to the mythology from which the god Makemake — the creator of humanity and the god of fertility — springs. Brown says the name is pronounced ‘maki-maki,’ and in the absence of any background in Polynesian languages, I’ll take his word for it. Interestingly, Brown goes on to say that coming up with a permanent name for Easterbunny was his biggest naming challenge. This really does get entertaining:

Easterbuuny? It’s orbit is not particularly strange, but it is big. Probably about 2/3 the size of Pluto. And it is bright. It is the brightest object in the Kuiper belt other than Pluto itself. Unlike, say 2003 EL61, which has so many interesting characteristics that it was hard choosing from so many different appropriate name (more on this later), Easterbunny has no obvious hook. Its surface is covered with large amounts of almost pure methane ice, which is scientifically fascinating, but really not easily relatable to terrestrial mythology. (For a while I was working on coming up with a name related to the oracles at Delphi: some people interpret the reported trance-like state of the oracles to be related to natural gas [methane] seeping out of the earth there. After some thought I decided this theme was just dumb.)

Although it’s tempting, I won’t quote the whole piece, but send you to Brown’s lively What’s In a Name? for more. Clearly, the Easter connection linking the object’s discovery with Easter Island was the deciding issue, and it’s one that lets Makemake join other KBOs in having a name that fits its station. Eris, for example, was the Greek goddess of discord, a fitting name for the object causing a planetary re-juggling that resulted in Pluto’s demotion to ‘dwarf planet.’ Orcus was an Etruscan counterpart to Pluto, and with its large moon, Orcus does resemble Pluto in many ways (some call it the ‘anti-Pluto’). Sedna was an Inuit goddess of the sea, a cold name for this incredibly distant world with the highly elliptical orbit.

Makemake Under Observation

As to its own composition, Makemake is about ⅔ the size of Pluto, with many astronomers expecting to find an atmosphere there. But observations with European Southern Observatory instruments in Chile have used a stellar occultation to determine that Makemake has no atmosphere of any significance. The occultation was highly useful — Makemake is a difficult object because of its lack of moons and the distance involved, and the new work not only offers up information about the lack of atmosphere but also helps us determine its size more accurately, as well as allowing estimates of its density. We also get an albedo measurement showing a reflectivity higher than Pluto’s but somewhat less than that of dwarf planet Eris.

Image: This diagram shows the path of the shadow of the dwarf planet Makemake during an occultation of a faint star in April 2011. Several sites in South America, including ESO’s La Silla and Paranal Observatories, saw the star disappear briefly as its light was blocked by Makemake. This dwarf planet is about two thirds of the size of Pluto, and travels around the Sun in a distant path that lies beyond that of Pluto, but closer to the Sun than Eris, the most massive known dwarf planet in the Solar System. Makemake was expected to have an atmosphere like Pluto, but the new occultation data show that this is not the case. Credit: ESO/L. Calçada.

José Luis Ortiz (Instituto de Astrofísica de Andalucía, CSIC, Spain), who led this work, comments on its significance:

“As Makemake passed in front of the star and blocked it out, the star disappeared and reappeared very abruptly, rather than fading and brightening gradually. This means that the little dwarf planet has no significant atmosphere. It was thought that Makemake had a good chance of having developed an atmosphere — that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies. Finding out about Makemake’s properties for the first time is a big step forward in our study of the select club of icy dwarf planets.”

These observations, combined with earlier work, indicate that Makemake’s density is 1.7 ± 0.3 grams per cubic centimeter. From this, the team infers that the object is in the shape of a sphere somewhat flattened at the poles, with axes of 1430 ± 9 kilometres and 1502 ± 45 kilometres. This ESO news release offers more details.

The star occulted by Makemake was NOMAD 1181-0235723, with an event lasting no longer than a minute. In all, seven different telescopes across Brazil and Chile were used in the observations. The paper on this work is Ortiz et al., “Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation,” Nature 491 (22 November 2012), pp. 566-569 (abstract).


Comments on this entry are closed.

  • Thomas Mazanec November 26, 2012, 11:14

    Just wondering…
    I can see the occultation giving the diameter, but if Makemake has no satellite, how does it give the density?

  • Rafal November 26, 2012, 13:03

    ‘maki-maki’ is a pronunciation natural for a native English speaker, but it is not the correct one. Rapanui letters’ pronunciation is based on Spanish and therefore ‘e’ is pronounced in a way natural to speakers of most continental European languages, but different than an English speaker could infer. In other words: /ɜ/ and not /ɪ/.

  • Rob Henry November 26, 2012, 14:55

    How could density possibly be determined to such tight bounds. Makemake has no moons for determining mass, so what clever trick am I missing?

  • jkittle November 27, 2012, 10:30

    Looking at the size of make-make reminds me that there is FAR more room for colonization in the widely dispersed worlds of the kuiper belt than the surface area of the earth. If colonies are built into shallow surface habitats to shield form radiation, then Mike Brown’s current list of objects bigger than about 300 Km diameter represent a huge resource. We need a practical energy source to colonize these frozen worlds… the expanded livingspace for billions of humans in the 4th millennium. Someday, humanity may look at these worlds and think “HOME”.

  • xcalibur November 27, 2012, 19:43

    Basically, the e in Makemake is pronounced with an “eh” sound. Even though English is my native tongue, I naturally assumed this.

    I believe Makemake was the right choice. But as we study the cosmos further, the naming of significant bodies will continue to be a challenge. I remember reading Rendezvous with Rama by Arthur C Clarke; in which the fictional future society had run out of Greco-Roman names, and relied on Hindu mythology to christen the alien object central to the story.

    It will be especially challenging for habitable exoplanets/exomoons.

  • Thomas Mazanec November 29, 2012, 9:30

    And when is 2007 OR10 going to get its name? It’s the largest unnamed object known in the Solar System.

  • ljk November 30, 2012, 10:22

    Thomas Mazanec said on November 29, 2012 at 9:30:

    “And when is 2007 OR10 going to get its name? It’s the largest unnamed object known in the Solar System.”

    What is wrong with calling it 2007 OR10? We really are going to run out of names from Western classical culture and eventually others as well as said above and then we run into the danger of giving worlds “cutesy” names. This has already happened to the last three Mars rovers and now there is the danger of the same happening to exoplanets:


    Regarding exoplanet names, you may find this paper from 2009 to be of interest:


  • ljk November 30, 2012, 12:44

    In contrast, we better start referring to Earth’s Sun and Moon as Sol and Luna, respectively, to differentiate them from the many billions of other suns and moons in the Milky Way galaxy. Besides, it is high time we gave the two most dominant and important celestial objects in our sky proper labels.

    We also better think about revamping our calendar system for the expansion and duration of our society: