Makemake- dwarf planet, plutoid, classic Kuiper belt object. Initially designated as 2005 FY9, later received the number 136472. According to astronomers at the Palomar Observatory (California), it has a diameter of 50% to 75% of the diameter of Pluto and ranks third (or fourth) in diameter among Kuiper Belt objects. Unlike other large trans-Neptunian objects, Makemake has not yet discovered any satellites, and therefore its mass and density remain uncertain.
The facility was opened on March 31, 2005 by a team led by Michael E. Brown. The discovery was announced on July 29, 2005 - the same day as two other large trans-Neptunian objects: Haumea and Eris. Clyde Tombaugh had the opportunity to observe Makemake in 1930, since the object at that time was only a few degrees from the ecliptic, on the border of the constellations Taurus and Auriga, and its apparent magnitude was 16m. However, it is too close to the Milky Way, making it very difficult to observe. Tombaugh continued searching for other trans-Neptunian objects for several years after the discovery of Pluto, but failed.
In July 2008, the International Astronomical Union, at the suggestion of Michael Brown, named the object Makemake, in honor of the deity of Rapa Nui mythology. Brown explained his choice of name by the fact that the facility was opened on the eve of Easter (the Rapanui people are the aborigines of Easter Island).
In 2009, Makemake was 52 a.m. away. that is, from the Sun, that is, almost at the aphelion. Makemake's orbit, like Haumea's, is inclined 29° and has an eccentricity of about 0.16. But, at the same time, its orbit is located slightly further than the orbit of Haumea, both along the semimajor axis and at perihelion. The object's orbital period around the Sun is 310 years, versus 248 for Pluto and 283 for Haumea. Makemake will reach its aphelion in 2033.
Unlike plutinos, classical Kuiper belt objects, to which Makemake, do not have an orbital resonance with Neptune (2:3) and do not depend on its disturbances. Like other Kuiper belt objects, Makemake has a slight eccentricity.
By decision of the International Astronomical Union in 2006, Makemake was included in the group of dwarf planets. On June 11, 2008, the IAU announced the identification of a subclass of plutoids in the class of dwarf planets. Makemake was included in it, along with Pluto and Eris.
Dwarf planet Makemake: interesting facts
The object is currently the second brightest after Pluto, with an apparent magnitude of 16.7m. This is enough to be visible in a large amateur telescope. Based on Makemake's albedo, we can conclude that the surface temperature is approximately 30 °K. The size of the dwarf planet is not known exactly, but according to studies carried out in the infrared range by the Spitzer telescope, and in comparison with the spectrum of Pluto, it is generally accepted that its diameter is about 1500 + 400 x 200 km. This is slightly larger than the diameter of Haumea, possibly making Makemake the third-largest trans-Neptunian object after Eris and Pluto. The absolute magnitude of this dwarf planet is ?0.48m, which guarantees that its size is sufficient to be a spheroid. Weight~4?1021 kg.
In a letter to the journal Astronomy and Astrophysics, Licandro and others reported on research conducted in the visible and long-infrared regions of Makemake. They used the William Herschel Telescope and Telescopio Nazionale Galileo and found that Makemake's surface was similar to that of Pluto. Methane absorption bands were also detected. Methane has also been found on Pluto and Eris, but in much smaller quantities.
Research has shown that the surface of Makemake may be covered with methane grains at least 1 cm in diameter. It is also possible the presence, and in large quantities, of ethane and tholin, arising from methane as a result of photolysis under the influence of solar radiation. The presence of frozen nitrogen is also assumed, although not in such quantities as on Pluto or, especially, on Triton.
It is assumed that the main component of Makemake's rarefied atmosphere may be nitrogen.
In 2007, a group of Spanish astronomers led by J. Ortiz determined by changing the brightness of Makemake its rotation period was 22.48 hours. In 2009, new measurements of brightness fluctuations carried out by American astronomers gave a new value for the period - 7.77 hours (about three times less). The authors of the study suggested that we now see Makemake almost from the pole, and to accurately determine the period we must wait several decades. 
Dwarf planet Makemake has no satellites. Moons, if they exist, would be detected even if the brightness was 1% of the dwarf planet's brightness and Makemake's distance was 0.4 arcseconds or greater.
The icy and deserted dwarf planet Makemake lives on the borders of the known world, far from our planet.
The progress of science and the creation of more advanced telescopes have made it possible to look into deep space. Looking at pictures from the Oshin telescope, while studying the planet Eris, M. Brown's group noticed another object in the photographs. The body had a significant magnitude (16.7), which gave reason to consider it quite large, comparable to Pluto. In July 2005, American researchers C. Trujillo, D. Rabinowitz and M. Brown made a statement about their discoveries and two new dwarf planets were presented to the astronomical world.
The search for a cosmic body in this area has been carried out for a long time, but without success. As often happens, a happy accident intervened in history. During the period of observations, the plutoid was in opposition. This is the most convenient position for study, when the Earth is located between the Sun and the object, its hemisphere is illuminated, and the time spent in the sky extends throughout the night. A year later, the cosmic body, along with others classified in the same category of “minor planets,” was entered into a special catalog under a personal number. In 2008, Brown's proposal was accepted to name the third plutoid after the creator of man, all natural resources and the Universe, the almighty god of the Rapanui people - Make-make.
Location
The trajectory of a minor planet in the Kuiper Belt has been tracked for several years. It has been determined that its deviation from the circle is small - 0.16; at perihelion the object is separated from the luminary by 6.8 billion km, and at aphelion - 7.9 billion km. Makemake periodically appears closer to the center of the system than Pluto, which is 7.4 billion km away. Since the emergence of the Solar System, the icy planet has clearly followed its path, without being influenced by Neptune. The annual cycle of a plutoid is 306 Earth years.
Structure and characteristics
The planet's size is calculated approximately based on the size of Pluto and infrared radiation readings. It is believed that it does not exceed 1400 km. This value is enough for Makemake, overtaking Haumea, to take third place among the dwarf planets. In 2001, Makemake obscured another celestial body, and this made it possible to clarify its diameter and shape. The coverage was expected by scientists at several observatories in Europe and South America. Such an event is very rare, and combining data from different telescopes increased the chances of success.
The planet turned out to be spherical, and its polar diameter - 1430 km - is slightly less than the equatorial one - 1502 km. At the same time, the density and mass of the object were assessed; they were 1.7 g/m3 and 3x10 in 21 kg, respectively. Analysis of Makemake's brightness gave different values several times; according to updated data, its rotation period is 7.7 hours.
The surface temperature of the dwarf planet rises slightly as it passes perihelion and becomes -239 degrees Celsius, while far from the star it is -244 degrees. The albedo indicator is quite high - 0.7.
Composition and atmosphere
Observations from the Spanish Roque de los Muchachos Observatory, made in the spectral range, helped establish the chemical composition of the planet's surface. It is covered with methane ice, which explains the high albedo, and its organic compounds with ethane. The resulting substance, tholin, has a reddish-brown light, which was noted during observations of Makemake. Nitrogen was not found in the composition, since, obviously, its reserves are very small.
The dwarf planet is quite impressive in size, and scientists expected to find an atmosphere on it. Confirmation of the hypothesis should have been provided by the covering of the star, but the eclipse of light was quite sharp, which means the complete absence of a gas envelope. Despite this result, scientists believe that the atmosphere on a small planet still appears periodically when approaching our star, and when moving away, it falls to the surface in the form of icy methane grains.
Satellite
Makemake satellite, image from the Hubble telescope
The Makemake satellite, discovered by the Hubble telescope on April 16, 2016, received the temporary designation S/2015 (136472) 1. It is more than 1,300 times fainter than Makemake itself. The distance from the satellite to the dwarf planet at the time of discovery was approximately 20,920 kilometers. The satellite's diameter is estimated at 160 kilometers (Makemake's diameter is 1,400 km).
Preliminary calculations show that if the satellite is in a circular orbit around Makemake, its orbital period is approximately 12 days.
The object is now on its way to its aphelion, which it will reach in 18 years, and its approach to the Sun will have to wait until 2187.
Makemake, a rocky celestial body and the third largest dwarf planet in our solar system, is located in a distant region of space - the Kuiper Belt, beyond the orbit of Pluto.
After the discovery of the planet in 2005, astronomers for a long time could not determine the size of Makemake, but some scientists suggested that it was smaller than Pluto.
During observations of Makemake in 2010 using the Spitzer Space Telescope, researchers calculated the diameter of the planet to be 1400-1600 km. This size is enough for Makemake to overtake another dwarf planet, Haumea, to become the third largest such planet. In addition, it turned out that Makemake is a slightly flattened ball that makes a full revolution around the Sun in 310 Earth years.
Studying the dwarf planet, astronomers came to the conclusion that the surface of Makemake contains methane and ethane in a frozen state in the form of grains, as well as nitrogen. Methane grains are about 1 cm in size, and ethane grains are about 0.1 mm in size. There is very little nitrogen on Makemak; a small amount of it is contained in methane ice. It is believed that nitrogen reserves have been exhausted throughout the entire existence of the planet. In all likelihood, a significant part of it was carried away by the planetary wind.
Astronomers also believe that there are tholins on the planet's surface that have a red tint, making Makemake appear slightly reddish. Tolins are organic substances. They are a mixture of different organic copolymers (substances whose molecular chains consist of two or more structural units). Shades characteristic of tholins are reddish-brown or reddish-orange. Tholins are formed whenever ultraviolet light from the sun interacts with ethane and methane.
An interesting phenomenon occurs with the atmosphere of Makemake. When the planet, moving in its orbit, approaches the Sun, granular methane and ethane heat up and, under the influence of heat, transform into their usual gaseous state. These gases then rise up and surround the planet with an atmospheric layer. The methane-ethane atmosphere exists as long as Makemake is in such a favorable “heat zone”. As the planet begins to move away from the Sun, moving into colder space terrain, methane and ethane freeze. They fall like snow flakes onto the surface and there take the form of grains.
Discovery of the planet
The first people to discover this planet were astronomers Michael Brown, David Rabinowitz and Chadwick Trujillo. They discovered Makemake on March 31, 2005, a few days after Easter, which fell on March 27 that year. Since the object was discovered almost immediately after the holiday, scientists wanted to name the new planet with a name somehow related to the word “Easter.” It was decided to give the planet the name of the mythological god of the Rapanui people - the inhabitants of Easter Island, Make-make - the god of abundance and the creator of humanity.
Interesting Facts
There are some areas on the planet that appear as dark lines and are inaccessible for observation. This is because Makemake's near-infrared spectrum is marked by strong methane absorption lines. At the frequencies of these lines, atoms absorb quanta of electromagnetic radiation, after which they re-emit the quanta in an arbitrary direction, and the mass of matter that makes up the surface of the planet begins to scatter the radiation in different directions.
In March 2016, a satellite was discovered in orbit of the planet, which was named MK 2. The diameter of the moon Makemake is 160 kilometers, and the body orbits the planet in 12 Earth days. Interestingly, MK 2 is a very dark object, while Makemake has a fairly bright surface due to the icy methane.
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Refers to plutoids. It is the largest known classical object.
History of discovery
Background
Despite the fact that Makemake is a fairly bright object and could have been discovered much earlier, for many reasons this did not happen. In particular, detecting a trans-Neptunian object during a search is unlikely, since the speed of movement of the TNO against the background is extremely low. But Makemake could not be found for a long time, either during searches in 1930 or during specialized searches for TNOs that began in the 1990s, since searches for minor planets are carried out mainly relatively close to the ecliptic due to the fact that the likelihood of discovering new objects in this area is maximum. But Makemake has a high inclination - at the time of its discovery it was high above the ecliptic, in the constellation Coma Berenices.
Opening
Makemake was discovered by a group of American astronomers. It included Michael Brown (Caltech), David Rabinowitz (Yale University), and Chadwick Trujillo (Gemini Observatory). The team used a 122-centimeter Samuel Oshin 112-CCD sensor located at the Palomar Observatory, as well as special software to search for moving objects in images.
Makemake was first spotted on March 31, 2005, in an image taken at 6:22 UTC that day by the Samuel Oshin Telescope. At the time of its discovery in March 2005, it was at opposition in the constellation Coma Berenices and had a magnitude of 16.7 (compared to Pluto's 15). The object was later found in photographs taken back in early 2003. The discovery announcement was officially released on July 29, 2005, at the same time as the discovery of another dwarf planet, .
Name
When registering its opening, the facility was designated 2005 FY9.
The group of astronomers who discovered the object gave it the nickname “Easterbunny”. Michael Brown explained it this way:
Three years is a long time to have just a plaque with a number instead of a name, so most of the time we just called the place "The Easter Bunny" in honor of the fact that it opened just a few days after Easter 2005.
On September 7, 2006, simultaneously with Pluto and Eris, it was included in the catalog of minor planets under the number 136472.
According to IAU rules, classical Kuiper Belt Objects (Kubiwanos) are given a name associated with creation. Michael Brown proposed to name it in honor of Make-make - the creator of humanity and the god of abundance in the mythology of the Rapanui people, the indigenous inhabitants of Easter Island. This name was chosen partly to preserve the connection between the object and Easter. On July 18, 2008, 2005 FY9 was given the name Makemake. Simultaneously with the assignment of the name, it was included in the number of dwarf planets, becoming the fourth dwarf planet and the third plutoid, along with Pluto and Eris.
Orbit
The orbits of Makemake (blue) and Haumea (green), compared with the orbit of Pluto (red) and the ecliptic (gray). Perihelion (q) and aphelion (Q) are marked with transit dates. The positions of the planets as of April 2006 are marked with spheres illustrating relative size and differences in albedo and color
Makemake's orbit has been tracked using archival images back to 1955. It is inclined to the ecliptic plane at an angle of 29°, moderately elongated - its eccentricity is 0.162, and the semimajor axis is 45.44 AU. e. (6.8 billion km). Thus, the maximum distance from Makemake to is 52.82 a. e. (7.9 billion km), minimum - 38.05 a. e. (5.69 billion km). Consequently, from time to time it may be closer to the Sun than Pluto, but does not enter the orbit. With its high inclination and moderate eccentricity, Makemake's orbit is similar to that of another dwarf planet, but it is somewhat further from the Sun along its semimajor axis and perihelion.
According to the CMP classification, Makemake belongs to the classical Kuiper belt objects (also called kyubiwano). Unlike plutinos, which are in a 2:3 resonance with Neptune, cubewanos orbit far enough from Neptune not to be subject to the gravitational disturbances it creates, allowing their orbits to remain stable throughout the solar system's existence. Such objects move around the Sun in planet-like orbits (they pass close to the ecliptic plane and are almost circular, like planets). However, Makemake is a member of the "dynamically hot" class of classical Kuiper belt objects, as it has a high inclination compared to the rest of the group. Therefore, some astronomers classify Makemake as an object.
Image of Makemake taken on November 26, 2009 through a 61 cm telescope (magnitude 16.9m)
As of 2012, Makemake was located at 52.2 a. e. (7.8 billion km) from the Sun, near the aphelion point, which it will reach in April 2033.
Makemake's absolute magnitude is −0.44m. Its apparent magnitude in 2012 is 16.9m, making Makemake the second brightest known Kuiper Belt object after Pluto. It is bright enough to be captured through a powerful amateur telescope with an aperture of 250-300 mm.
Makemake's orbital period around the Sun is 306 years. Accordingly, the closest passage of perihelion will occur in 2187 (the last time this happened was in 1881). At this time, its apparent magnitude will reach 15.5m, which is only slightly less than the brightness of Pluto, with which they will be almost at the same distance from the Sun.
physical characteristics
The exact size of Makemake is unknown. A rough initial estimate is that its diameter is three-quarters that of Pluto.
Measurements of the size of the object, carried out in 2010 using the Infrared Space Observatory, showed that its diameter lies in the range of 1360-1480 km.
Comparative sizes of the largest TNOs and the Earth.
Thus, Makemake's diameter is slightly larger than Haumea's, making it the third largest trans-Neptunian object after Pluto and Eris. This allows us to confidently say that Makemake is large enough to reach a state of hydrostatic equilibrium and take the shape of a spheroid flattened at the poles. Therefore, it meets the definition of a dwarf planet.
This assumption was confirmed after the most accurate measurement of the size of Makemake during its occultation of the very faint star NOMAD 1181-0235723 (apparent magnitude 18.2m) in the constellation Coma Berenices, which occurred on the night of April 23, 2011. The event was recorded by five observatories in South America. As a result, it was found that the equatorial diameter of Makemake is 1502 ± 45 km, the polar diameter is 1430 ± 9 km.
The mass of Makemake has not yet been precisely established. It is easier to measure the mass of an object if it is available, but until 2016 it was believed that the planet had no satellites. This made it difficult to obtain accurate data on Makemake's mass. If we assume that its density is equal to the average density of Pluto - 2 g/cm³, then the mass of Makemake can be estimated at 3·10 21 kg (0.05% of the mass). From data on the planet's coverage of the star, a relatively rough estimate of the object's density was obtained: 1.7 ± 0.3 g/cm 3 .
Makemake's rotation period is not precisely known. In 2007, an analysis of the light curve constructed using telescopes at the Sierra Nevada and Calar Alto observatories was published. According to these data, Makemake has two periods of brightness change: 11.24 and 22.48 hours. Researchers believed that the second most likely corresponds to the rotation period.
According to a study of Makemake's brightness published in 2009 using the Kuiper Telescope at the Steward Observatory, its rotation period is 7.771 ± 0.003 hours. This result is in good agreement with the results of the analysis of Makemake's brightness in 2005-2007, published in 2010, according to which the object's rotation period is 7.65 hours.
The tilt of Makemake's rotation axis is unknown.
Chemical composition
Makemake as imagined by an artist
Taking into account that Makemake's albedo is about 0.7, at the current distance from the Sun the equilibrium temperature on its surface is about 29 K (−244 °C), and at the point of orbit closest to the Sun the temperature can reach 34 K (−239 °C ).
When exploring Makemake with the Spitzer and Herschel space telescopes, it was discovered that Makemake's surface is heterogeneous. Although most of the surface is covered with methane snow, and the albedo there reaches 0.78-0.90, there are small areas of darkened landscape that cover 3-7% of the surface, where the albedo does not exceed 0.02-0.12.
In 2006, the results of an analysis of the spectrum of Makemake in the wavelength range 0.35-2.5 microns were published using the William Herschel and Galileo telescopes at the Roque de los Muchachos Observatory. Researchers have found that its surface is similar in chemical composition to the surface of Pluto, in particular, the near-infrared spectrum is marked by strong absorption lines of methane (CH4), and in the visible range the red color predominates, which is apparently due to the presence of tholins.
Although another study published in 2007 revealed significant differences in the spectra of Makemake and Pluto, expressed primarily in the presence of ethane on Makemake and the absence of nitrogen (N2) and carbon monoxide (CO). The authors also suggested that the unusually wide lines of methane are due to the fact that it is present on the surface of the object in the form of large (about 1 cm in size) grains. Ethane apparently also forms grains, but much smaller ones (about 0.1 mm).
In 2008, a study was published proving that, most likely, there is nitrogen on Makemak. It is present as an impurity in methane ice, giving slight shifts in the methane spectrum. True, the proportion of nitrogen ice is incomparably small with the amount of this substance on Pluto and, where it makes up almost 98% of the crust. The relative scarcity of nitrogen ice means that nitrogen reserves were somehow depleted during the existence of the solar system.
Data obtained during the Makemake star's 2011 occultation show that the planet, unlike Pluto, currently has no atmosphere. The pressure at the surface of the planet at the time of observation does not exceed 4-12·10 −9 atmospheres. However, the presence of methane and possibly nitrogen makes it likely that Makemak has a temporary atmosphere similar to the one that appears at Pluto at perihelion. Nitrogen, if present, would be the dominant component of this atmosphere. The existence of a temporary atmosphere would provide a natural explanation for Makemak's nitrogen deficiency: since the planet's gravity is weaker than that of Pluto, Eris, or Triton, large amounts of nitrogen may have been blown away by planetary winds; methane is lighter than nitrogen and has a significantly lower vapor pressure at temperatures prevailing on Makemak (30-35 K), which prevents its loss; the result of these processes is a significantly higher concentration of methane.
Satellite
For a long time, not a single satellite could be detected in orbit around Makemake. It was found that Makemake has no satellites with a brightness of more than 1% of the planet’s brightness and located at an angular distance from it no closer than 0.4 arcseconds. The lack of moons distinguished Makemake from other large trans-Neptunian objects, which almost all have at least one moon: Eris one, Haumea two, and Pluto five. It is believed that between 10 and 20% of trans-Neptunian objects have one or more satellites.
Therefore, the search continued, and in 2016 the brightness was 0.08% of the brightness of the dwarf planet. He received the designation.
Dwarf planets didn't actually exist until 2006. Then they were allocated to a new class. The purpose of such a transformation was to introduce an intermediate link between large planets and numerous asteroids to prevent confusion in the names and statuses of new bodies discovered beyond the orbit of Neptune.
Definition
Then, back in 2006, the next meeting of the IAU (International Astronomical Union) took place. On the agenda was the question of specifying the status of Pluto. During the discussions, it was decided to deprive him of the “title” of the ninth planet. The IAU has developed definitions for some space objects:
- A planet is a body orbiting the Sun that is massive enough to maintain hydrostatic equilibrium (that is, have a rounded shape) and clear its orbit of other objects.
- An asteroid is a body orbiting the Sun that has a low mass that does not allow it to achieve hydrostatic equilibrium.
- A dwarf planet is a body orbiting the Sun that maintains hydrostatic equilibrium, but is not massive enough to clear its orbit.
Pluto was included among the latter.
New status
Pluto is also classified as a Kuiper belt body. Like some other dwarf planets, it is classified as a Kuiper belt body. The impetus for revising the status of Pluto was the numerous discoveries of objects in this distant part of the solar system. Among them was Eris, which exceeds Pluto in mass by 27%. Logically, all these bodies should have been classified as planets. That is why it was decided to revise and specify the definitions of such space objects. This is how dwarf planets appeared.
Tenth
It wasn't just Pluto who was "demoted in rank." Eris, before the IAU meeting in 2006, claimed the “title” of the tenth planet. It surpasses Pluto in mass, but is inferior to it in size. Eris was discovered in 2005 by a group of American astronomers searching for trans-Neptunian objects. Initially she was called Xena or Zena, but later they began to use the modern name.
Eris, like other dwarf planets in the Solar System, has hydrostatic equilibrium, but is not able to clear its orbit of other cosmic bodies.
Third on the list
The next largest after Pluto and Eris is Makemake. This is a classic Kuiper belt object. The name of this body has an interesting story. As always, upon opening it was assigned the number 2005 FY 9. For a long time, the team of American astronomers that discovered Makemake called it among themselves the “Easter Bunny” (the discovery was made a few days after the holiday).
In 2006, when a new column “Dwarf planets of the Solar System” appeared in the classification, it was decided to call 2005 FY 9 differently. Traditionally, classical Kuiper Belt objects are named after deities associated with creation. Make-make is the creator of humanity in the mythology of the Rapanui people, the original inhabitants of Easter Island.
Haumea
The dwarf planets of the Solar System also include another trans-Neptunian object. This is Haumea. Its main feature is very fast rotation. In this parameter, Haumea is ahead of all known objects with a diameter of more than one hundred meters in our system. Among dwarf planets, the object ranks fourth in size.
Ceres
Another one belonging to this class is located in the Main, lying between the orbits of Jupiter and Mars. This is Ceres. It was opened at the beginning of 1801. For some time it was considered a full-fledged planet. And in 1802, Ceres was classified as an asteroid. The status of the cosmic body was revised in 2006.
Dwarf planets differ from their large neighbors mainly in their inability to clear their own orbit from other bodies. It is difficult to say now how convenient such an innovation is to use - time will tell. In the meantime, the controversy over the downgrading of Pluto's status has only subsided a little. However, the value of the former ninth planet and similar bodies for science remains high regardless of what they are called.