November 22nd, 2012 by James Ayre
Makemake is one of the largest known dwarf planets in the solar system, at around two thirds of the size of Pluto. It follows a very distant orbit around the Sun, far beyond the of Pluto but closer than the largest dwarf planet Eris.
Some of the few observations that we have of the ice dwarf suggest that it is similar to other dwarf planets. Which has led to the assumption that it would have an atmosphere similar to the other ice dwarfs, such as Pluto. But new research has shown that to not be true. Like the largest dwarf, Eris, Makemake doesn’t have a substantial atmosphere.
For the new research, multiple observations were combined “using three telescopes at ESO’s La Silla and Paranal observing sites in Chile — the Very Large Telescope (VLT), New Technology Telescope (NTT), and TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) — with data from other small telescopes in South America, to look at Makemake as it passed in front of a distant star.”
“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,” says Jose Luis Ortiz. “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.”
The huge distance from the Sun at which Makemake orbits, and also its lack of moons, make it hard to study. The limited amount that we do know is very approximate. “The team’s new observations add much more detail to our view of Makemake — determining its size more accurately, putting constraints on a possible atmosphere and estimating the dwarf planet’s density for the first time. They have also allowed the astronomers to measure how much of the Sun’s light Makemake’s surface reflects — its albedo. Makemake’s albedo, at about 0.77, is comparable to that of dirty snow, higher than that of Pluto, but lower than that of Eris.”
“It was only possible to observe Makemake in such detail because it passed in front of a star — an event known as a stellar occultation. These rare opportunities are allowing astronomers for the first time to find out a great deal about the sometimes tenuous and delicate atmospheres around these distant, but important, members of the Solar System, and providing very accurate information about their other properties.”
“Occultations are particularly uncommon in the case of Makemake, because it moves in an area of the sky with relatively few stars. Accurately predicting and detecting these rare events is extremely difficult and the successful observation by a coordinated observing team, scattered at many sites across South America, ranks as a major achievement.”
“Pluto, Eris and Makemake are among the larger examples of the numerous icy bodies orbiting far away from our Sun,” says Jose Luis Ortiz. “Our new observations have greatly improved our knowledge of one of the biggest, Makemake — we will be able to use this information as we explore the intriguing objects in this region of space further.”
Makemake was discovered only very recently known, a couple of days after Easter in March 2005. It was given the official name of Makemake in 2008. Makemake was the creator of humans and the god of fertility in the stories of the people of Easter Island.
Some basic information of Makemake:
“Makemake is a dwarf planet and perhaps the largest Kuiper belt object in the classical population, with a diameter that is probably about 2/3 the size of Pluto. Makemake has no known satellites, which makes it unique among the largest KBOs and means that its mass can only be estimated. Its extremely low average temperature, about 30 K (−243.2 °C), means its surface is covered with methane, ethane, and possibly nitrogen ices.”
Image Credits: ESO/L. Calçada/Nick Risinger (skysurvey.org); Makemake via Wikimedia Commons
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