ESO: Dwarf Planet Makemake Lacks Atmosphere

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ESO: Dwarf Planet Makemake Lacks Atmosphere

Post by bystander » Wed Nov 21, 2012 8:22 pm

Dwarf Planet Makemake Lacks Atmosphere
European Southern Observatory | 2012 Nov 21
Distant frigid world reveals its secrets for the first time
Astronomers have used three telescopes at ESO’s observatories in Chile to observe the dwarf planet Makemake as it drifted in front of a distant star and blocked its light. The new observations have allowed them to check for the first time whether Makemake is surrounded by an atmosphere. This chilly world has an orbit lying in the outer Solar System and was expected to have an atmosphere like Pluto (eso0908), but this is now shown not to be the case. The scientists also measured Makemake’s density for the first time. The new results are to be published in the 22 November issue of the journal Nature.

Dwarf planet Makemake [1] 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 (eso1142). Previous observations of chilly Makemake have shown it to be similar to its fellow dwarf planets, leading some astronomers to expect its atmosphere, if present, to be similar to that of Pluto. However, the new study now shows that, like Eris, Makemake is not surrounded by a significant atmosphere.

The team, led by José Luis Ortiz (Instituto de Astrofísica de Andalucía, CSIC, Spain), combined multiple observations 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 [2], to look at Makemake as it passed in front of a distant star [3].

“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 José 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.”

Makemake’s lack of moons and its great distance from us make it difficult to study [4], and what little we do know about the body is only 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 [5]. 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 José 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.”
  1. Notes:

    [*] Makemake was initially known as 2005 FY9. It was discovered a few days after Easter in March 2005, earning it the informal nickname of Easterbunny. In July 2008 it was given the official name of Makemake. Makemake is 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 recognised by the International Astronomical Union. The others are Ceres, Pluto, Haumea and Eris. Further information about dwarf planets and planets is available from the International Astronomical Union.

    [*] Another of the telescopes used in this observing campaign was an 0.84-metre telescope installed by the Católica del Norte University of Chile. This telescope is sited on Cerro Armazones, the future site of the European Extremely Large Telescope (E-ELT).

    [*] Makemake passed in front of faint star NOMAD 1181-0235723 (where NOMAD refers to the Naval Observatory Merged Astrometric Dataset) on 23 April 2011. The team observed this event using seven different telescopes across Brazil and Chile. The event only lasted about one minute, so the astronomers took advantage of a specialised high-speed camera known as ULTRACAM (eso0520) and a high-speed infrared imager named ISAAC to capture the event.

    [*] In the case of objects that are orbited by one or more moons the motions of the moons can be used to deduce the mass of the object. This was not possible in the case of Makemake.

    [*] The dwarf planet was calculated to have a geometrical albedo of 0.77 ± 0.03, greater than Pluto’s, but smaller than that of Eris. An albedo of 1 represents a perfectly reflecting body, and 0 a black surface that does not reflect at all. The observations, together with previous results, indicate that Makemake has a density of 1.7 ± 0.3 grams per cubic centimetre, which in turn allowed the team to infer the shape and appearance of an oblate spheroid — a sphere flattened slightly at both poles — with axes of 1430 ± 9 kilometres and 1502 ± 45 kilometres. Makemake shows no global Pluto-like atmosphere at a level of one thousandth of that of Pluto's atmosphere. However, it may have an atmosphere that only covers part of the surface. Such a local atmosphere, which is possible in theory, is not excluded by the observations.

Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation - J. L. Ortiz et al
ScienceShot: Breathless Orb
Science NOW | Sid Perkins | 2012 Nov 21
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: ESO: Dwarf Planet Makemake Lacks Atmosphere

Post by neufer » Wed Nov 21, 2012 9:07 pm

No atmosphere!!!

Just Make a couple of Martha Stewart Drink Parasols to fix up that situation!
http://en.wikipedia.org/wiki/Makemake_%28mythology%29 wrote: <<Makemake (MAH-kay MAH-kay) in the Rapa Nui mythology of Easter Island, was the creator of humanity, the god of fertility and the chief god of the "Tangata manu" or bird-man cult (this cult succeeded the island's more famous Moai era).

The trans-Neptunian dwarf planet, originally designated 2005 FY9, is named Makemake in an allusion to the shared connection of the dwarf planet and Easter Island with Easter. (The dwarf planet was discovered shortly after Easter 2005; the first European contact with Easter Island was on Easter Sunday 1722.) The planet's code name was "Easterbunny," since the planet was discovered on Easter, to name it after Easter Island mythology over Roman Mythology, and thus the name Makemake was chosen.>>
Last edited by neufer on Wed Nov 21, 2012 9:43 pm, edited 1 time in total.
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Astrophile: How a faraway dwarf world lost its cloak

Post by bystander » Wed Nov 21, 2012 9:13 pm

How a faraway dwarf world lost its cloak
New Scientist | Astrophile | Jeff Hecht | 2012 Nov 21
Object: Pluto's neighbour Makemake
Distance: About 8 billion kilometers
Image
The artist's-eye view from Makemake
(Image: ESO/L. Calçada/Nick Risinger (skysurvey.org))

Foraging in the Kuiper belt on the outskirts of the solar system, the dwarf planet Makemake is no stranger to icy conditions. Farther afield lies Eris, a white world that is coated in frost. Closer to the sun than both of them sits Pluto, which gets just enough heat to vaporise the rime, granting the ruling dwarf a thin atmosphere of nitrogen gas.

Makemake, meanwhile, feels a bit cheated. It is big enough and just about close enough to the sun that everyone expected it to have an atmosphere like Pluto's. But a fresh look has revealed the dwarf planet has only hints of a patchy, threadbare cloak.

Astronomers now think Makemake is less dense than Pluto, so it could not hold on to its atmosphere. These new details show that dwarf planets are surprisingly diverse, and may help us better understand how atmospheres form and evolve on rocky worlds.

Named after a Rapa Nui fertility god, Makemake appears to be about two-thirds the diameter of Pluto, so it should be massive enough to be almost round. Chemical clues gathered from its light hint that the world is covered in methane ice with a dash of nitrogen. Based on size and chemistry, Makemake should have an atmosphere.

Watching for winks

But the distant body is tough to resolve on its own. So last year a team led by Jose-Luis Ortiz of the Institute of Astrophysics of Andalusia in Granada, Spain, used a rare type of eclipse to tease out new details. Telescopes across South America watched as Makemake passed in front of a background star, causing it to wink out briefly.

Changes in starlight due to these stellar occultations can reveal an object's size, how reflective it is and whether it has an atmosphere.

We know from previous occultations by Pluto that it has a thin nitrogen atmosphere and is not very reflective. Occultations by Eris reveal that it is almost the same size as Pluto, but is much shinier. This is probably because its atmosphere froze and coated the surface in fresh ice.

Makemake falls in between. Its occultation showed that it reflects 77 percent of incoming light and has no significant atmosphere. The team concludes that the dwarf planet must be such a lightweight that it lost the bulk of its nitrogen in its youth.

"We believe that Makemake probably had plenty of nitrogen ice in the ancient past, like Pluto and Eris, but because Makemake is not very massive, its gravity could not retain the gas," says Ortiz. The nitrogen sublimated &ndash changed from ice directly into a gas – over aeons, leaving mostly methane behind.

Tufts of methane

The middling shininess matches previous observations of heat coming from Makemake's surface, which revealed dark spots that absorb more sunlight. It is possible that methane is sublimating into tufts of the gas that hover over these warm dark patches, but they may be in the wrong places for us to see them during an occultation.

Francis Nimmo of the University of California, Santa Cruz, who was not involved in the study, agrees with the team's findings. In the very long term, he adds, the family of dwarf planets will evolve into worlds that are very different from each other. "When the sun becomes a red giant... Kuiper belt objects will become warmer and develop much thicker atmospheres. Pluto's atmosphere will then be completely different from Makemake's, because it managed to hold onto a different set of gases."

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Re: ESO: Dwarf Planet Makemake Lacks Atmosphere

Post by Ann » Wed Nov 28, 2012 3:05 pm

Makemake love, not air!

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Re: ESO: Dwarf Planet Makemake Lacks Atmosphere

Post by neufer » Wed Nov 28, 2012 3:16 pm

Art Neuendorffer