November 21, 2012
Dwarf Planet Does Not Have Much Of An Atmosphere
[ Watch the Video: The Occultation of Dwarf Planet Makemake ]
Lee Rannals for redOrbit.com - Your Universe Online
The planet is about two-thirds 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.
Previous observations have shown Makemake to be similar to its fellow dwarf planets, but the new study shows that Makemake is not surrounded by a significant atmosphere, much like Eris.
The team combined multiple observations using three telescopes, including the Very Large Telescope (VLT), New Technology Telescope (NTT), and TRAnsiting Planets and PlanetesImals Small Telescope (TRAPPIST).
“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,” according to JosÃ© Luis Ortiz, an astronomer on the project.
“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 dwarf planet's lack of moons and its distance from us makes it a difficult planet to study. The new observations add much better understanding about the planet, giving scientists a better idea of its size, putting constraints on the possible atmosphere, and estimating the planet's density for the first time.
The astronomers were also allowed to measure how much of the Sun's light Makemake's surface reflects.
It was only possible to observe Makemake in detail because it passed in front of the star, NOMAD 1181-0235723. Opportunities like these are allowing astronomers to find out a great deal about the sometimes tenuous and delicate atmosphere around these dwarf planets.
“Pluto, Eris and Makemake are among the larger examples of the numerous icy bodies orbiting far away from our Sun,” JosÃ© Luis Ortiz said. “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 a few days after Easter in March 2005, earning itself the informal nickname of Easterbunny. The planet is named after the creator of humanity and god of fertility in the myths of the native people of Easter Island.
Makemake is one of five dwarf planets so far recognized by the International Astronomical Union. The other planets include Pluto, Ceres, Haumea and Eris.