The dwarf planet that nobody told you about

Hiding in the shadows of the Kuiper belt lies a dwarf planet which very few people have heard of: MAKEMAKE.

The dwarf planet is discovered very recently, but it was one of the reasons why Pluto was declared as a dwarf planet.

Makemake is one of the five dwarf planets officially recognized by IAU (International Astronomical Union).

Discovery

Makemake was discovered on March 31, 2005, by Mike Brown, C.A. Trujillo and D. Rabinowitz at Palomar observatory. They are also credited with the discovery of Eris, another dwarf planet in the Kuiper belt.

Clyde Tombaugh could have discovered Makemake when he discovered Pluto, but the planet was almost impossible to find against the dense background of stars.

Naming

Does Makemake mean doing something twice?

Nah…

Makemake was discovered just a few days after Easter so Mike and his team nicknamed it “Easter bunny”. The provisional name 2005 FY9 was given when Makemake’s discovery was made public.

In 2008, IAU named it Makemake after the god of fertility in Rapa Nui mythology. Since the Rapa Nui tribe lived on Ester island, it was named Makemake pronounced MAH-keh MAH-keh to keep it related to the word Easter.

Size and distance

With a radius of approximately 444 miles (715 km), Makemake is two-third the size of Pluto and just smaller than Haumea. Makemake is also the 25th largest object in the solar system.

It is 45.8 AU away from the Sun which is about 4,253,000,000 miles (6,847,000,000 km).

It takes sunlight 6 hours and 20 minutes to travel from Sun to Makemake.

Makemake is the second brightest object in the Kuiper belt (from Earth) behind Pluto.

Orbit and rotation

The rotation period of Makemake is similar to Earth’s with 22.48 hours. It makes one trip around the Sun in 305 years which is more than Pluto’s 248 years.

Makemake's orbit and rotation
Makemake’s orbit
Tomruen [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]

Makemake is a classical Kuiper belt object (KBO), this means its orbit lies far enough from Neptune to not be significantly affected by Neptune’s gravity (unlike Pluto) and will remain stable over the age of the solar system.

Surface and Atmosphere

Makemake lacks a substantial atmosphere, unlike Pluto which has a very thin atmosphere.

It is reddish-brown in color which might be because of the presence of Methane at its surface. Besides methane, some amount of ethane, ethylene, and alkanes may also be present.

Makemake may develop a very thin atmosphere of nitrogen near perihelion.

Gravity on Makemake’s surface is only 0.5 m/s^2. It has a density of 1.7 grams per cubic centimeter similar to that of Pluto.

Very little is known about the magnetosphere and internal structure of the dwarf planet.

Moon

All dwarf planets except Ceres have one or moons orbiting them. Finding Makemake’s moon proved to be a little tricky.

Makemake’s moon S/2005 (MK2) was discovered 10 years after the discovery of the parent planet using Hubble telescope by Alex Parker.

MK2 is thought to be 175 km (110 miles) in diameter (albedo of 4%). The object is orbiting the planet at an average distance of 13,000 miles (21,000 km).

Its orbital period is >= 12 days.

Makemake’s exact orbit is not known. Its orbit type may tell us how the moon came into existence.

If circular: the moon is created by a giant impact like Pluto’s moons.

If elliptical: trapped in Makemake’s orbit like Phobos and Deimos of Mars.

Although Makemake is the second brightest object in the Kuiper belt, it’s moon MK2 is dark as charcoal and is 1300 times fainter than Makemake.

One possible explanation for this is that its gravity is not strong enough to prevent bright but volatile ices from being lost in space when it is heated by the distant Sun.

You can read the article written by Alex Parker about his discovery here: A Moon for Makemake

No spacecraft has ever visited Makemake and currently, there are no plans to do so, in the future

Conclusion

Having been discovered just a decade ago we still don’t know much about this mysterious dwarf planet. Planet’s distance from Earth also makes it a very difficult object to study.

Maybe in the future, we will be able to send spacecraft to explore this dwarf planet.

How do you think Makemake’s surface will look like?

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