\u003e Dwarf planets
All information about dwarf planets Solar system for children: what it is, size, list of dwarf planets with photos, large Pluto and Ceres, distance.
To begin explanation for children parents or teachers at school may be due to the fact that the dwarf planets of the solar system are small worlds, whose size does not allow them to become full-fledged planets. However, they are too large to be moved to another category.
Can explain to children situation on the example of Pluto. At one time, he made a lot of noise, and even now disputes about his status do not stop. It no longer plays the role of the ninth planet and has shifted to a dwarf position.
For the little ones it will be interesting to know that up to 200 dwarf planets may exist at the moment. But not all children and even parents understand the difference between a dwarf and a full-fledged planet. Next, you will learn a lot interesting facts about the dwarf planets of the solar system, get acquainted with the description of worlds like Pluto and Eris, and also be able to see them in photos, drawings, pictures and diagrams. It is also interesting to understand where the names came from and what the orbits of the dwarf planets look like.
Dwarf planets - an explanation for the kids
The basic definition is given by the International Astronomical Union (IAU). According to him, the planet must revolve around the Sun, have sufficient gravity to become a sphere and clear the orbit of small objects. The last requirement will be especially important. Gravity attracts or repels other objects in its orbit. Dwarfs don't have enough of it to match.
For 2015, the IAU recognizes and lists 5 dwarf planets: Ceres, Pluto, Eris, Haumea and Makemake. There are also candidates (Sedna and Kwavare) beyond Pluto, and 2012 VP113, which has one of the most distant orbits. NASA believes there are at least 100 more dwarfs waiting to be discovered.
But controversy over Pluto's status is heating up every year. Moreover, the New Horizons mission can play a major role in this.
Many consider the requirement to "clear the orbit" as something absurd and wrong. The scientist Alan Stern also intervened for Pluto. At the end of 2014, Harvard-Smithsonian University broadcast What is a Planet ?, after which the audience voted for the planetary status of Pluto.
To begin explanation for children stands with the fact that Ceres is the earliest and smallest dwarf planet. It was discovered in 1801 by an astronomer from Italy, Giuseppe Piazzi. It occupies a diameter of 950 km, and the mass reaches only 0.015% of the earth's.
It is so tiny that it is classified as both a dwarf and an asteroid. It is ¼ the mass of all asteroids, but loses in size to Pluto. It has an almost round body and rocky composition with the possibility of water ice. In 2014, the release of water vapor was observed from two parts of the dwarf.
Pluto is the most famous and popularly discussed dwarf. It was discovered in 1930, and as a planet it lasted until 2006. Its orbit is unusual, because it periodically becomes closer to the Sun than Neptune.
Although it reaches only 0.2% of the Earth's mass and 10% of the mass of our Moon, its gravity is enough to hold 5 satellites. Contact with the huge moon Charon forces scientists to consider them as a binary system, because they rotate around a point between themselves.
Erida was once considered the largest dwarf (27% more than Pluto's mass) with a diameter of 2300-2400 km. It was she who made the IAU take a fresh look at the definition of planets. Its orbit is unstable, so Eris crosses the route of Pluto and even Neptune. Spends 557 years on the orbital path. At the most distant point, it goes beyond the border of the Kuiper belt.
They were named recently. Haumea attracts attention with its ellipsoid shape, which is one of the planetary criteria. Due to its rapid rotation, it is elongated, and its mass is three times less than Pluto. The axial revolution takes 4 hours, which can be explained by an early collision. It also has a red spot and a layer of crystal ice... It is the only object in the Kuiper belt (not counting Pluto) with multiple moons.
Makemake is also interesting because he has no companion. Because of this, it is difficult to determine its mass, although its diameter is 2/3 less than that of Pluto. Interestingly, if there were no new requirements from the IAU, then Makemake could be considered a planet.
Plutoids
Pluto, Haumea, Eris and Makemake are called plutoids. It is a subdivision of dwarfs orbiting outside of Neptune. Sometimes they are also called ice dwarfs because of the frost on the surface and their small size. The outer planets show their contact with the plutoids. For example, Neptune's largest moon, Triton, may be plutoid.
If you want to supplement the characteristics of dwarf planets, then you can always use the 3D model of the solar system on the site and consider the maps of dwarf planets, features of their surface and movement in orbit around the sun. It would also be interesting for children to look at the worlds in an online telescope in real time, but they are too small and far away for such observation. Therefore, consider photos, pictures and images from spacecraft.
Objects beyond the orbit of Neptune.
The dwarf planets Pluto, Haumea, Makemake, Eris and other large trans-Neptunian objects in comparison in size, albedo, and color. Their companions are also shown.
A dwarf planet, as defined by the International Astronomical Union, is a celestial body that:
orbits around;
has sufficient mass in order to maintain hydrostatic equilibrium under the action of gravitational forces and have a nearly spherical shape;
is not ;
cannot clear the area of \u200b\u200bits orbit from other objects.
The term "dwarf planet" was adopted in 2006 as part of the classification of bodies orbiting the sun and other bodies into three categories. Bodies large enough to clear space in their orbital strip are defined as planets, and not large enough to even achieve hydrostatic equilibrium as or. Dwarf planets occupy an intermediate position between these two categories. This definition met with both approval and criticism, and is still disputed by some scholars. For example, as the simplest alternative, they propose a conditional division between planets and dwarf planets in size or even: if more then - a planet, if less - a planetoid.
The International Astronomical Union officially recognized 5 dwarf planets: the largest asteroid and -,; however, it is possible that at least 40 more of the known objects in the world belong to this category. According to various estimates of scientists, up to 200 dwarf planets can be found in and up to 2000 dwarf planets beyond.
Classification of bodies with characteristics of dwarf planets in others planetary systemsah not defined.
List of dwarf planets
In 2006, the IAU officially named three bodies, which immediately received the classification of dwarf planets - the former planet Pluto, considered the largest trans-Neptunian object, Eris and the largest asteroid Ceres. Later, two more trans-Neptunian objects were declared dwarf planets. The term "dwarf planet" should be distinguished from the concept of "minor planet", which is also historically called asteroids.
| Name | Ceres | Pluto | Haumea | Makemake | Eris | Sedna |
|---|---|---|---|---|---|---|
| CMP number | 1 | 134340 | 136108 | 136472 | 136199 | 90377 |
| Designations | A899 OF; | 2003 EL 61 | 2005 FY 9 | 2003 UB 313, | 2003 VB 12 | |
| Area Solar system |
Asteroid belt | Kuiper Belt | Kuiper Belt | Kuiper Belt | Scattered disc | Oort Cloud |
| Diameter (km) | 963 × 891 | 2370 ± 20 | 1960 × 1518 × 996 | 1478 ± 34 | 2326 ± 12 | 995 ± 80 km |
| Weight in kg | 9.4 ± 0.1 10 20 | 1.305 10 22 | 4.2 10 21 | ~ 3 10 21 kg | ~ 1.67 10 22 | 8.3 1020-7.0 1021 kg |
| Middle equatorial radius* |
0,0738 471 |
0,180 1148,07 |
~750 | 0,19 ~1300 |
||
| Volume * | 0,0032 | 0,053 | 0,013 | 0,013 | 0,068 | |
| Density (t / m³) | 2,161 | 1,86 | 2.6 g / cm³ | 1.7 ± 0.3 g / cm³ | 2,52 | 2.0? g / cm³ |
| Acceleration free falling on equator (m / s²) |
0,27 | 0,60 | ~ 0.44 m / s² | ~ 0.4 m / s² | ~0,68 | 0.33-0.50 m / s² |
| The first space speed (km / s) |
0,51 | 1,2 | ||||
| Period of circulation [T ] (day) |
9 h 4 min 27.01 s | −6.387 Earth | (3.9154 ± | 7.771 ± 0.003 | 25.9 h | 0.42 d (10 h) |
| Period rotation |
0,3781 | −6.38718 (retro-hail) | 102,937 d | 111867 days (306.28 years) | 203 830 days (558.04 years) | about 4 404 480 d (12 059.06 a) |
| Orbital radius * (a.u.) semi-major axis * the same in km |
2,5-2,9 2,766 413 715 000 |
29,66-49,30 39,48168677 5 906 376 200 |
37,77-97,56 67,6681 10 210 000 000 |
541.429506 a. e. | ||
| Period circulation * (years) |
4,599 | 248,09 | 281,83 | 306,28 | 557 | 12059,06 |
| Average orbital speed (km / s) |
17,882 | 4,666 | 4.484 km / s | 4.419 km / s | 3,437 | 1.04 km / s |
| Eccentricity | 0,080 | 0,24880766 | 0,1975233 | 0,16254481 | 0,44177 | 0,8590486 |
| Mood | 10.587 ° | 17.14175 ° | 28.201975 ° | 29.011819 ° | 44.187 ° | 11.927945 ° |
| Mood plane equator to orbital plane |
4 ° | 119.61 ° | ||||
| Temperature (° C) | -106,15 | -233,15 | -223 ° C | -240,65 | −253 ° C | |
| Average surface temperature (K) |
167 | 40 | 50 C | 30-35 K (based on | 30 | |
| Number of known satellites |
0 | 5 | 2 | 1 | 1 | 0 |
| Perihelion | 381,028,000 km (2.5465 AU) | 29.667 a. e | 34,494401 | 38.050866 a. e. | 37.911 a. e. | 76.315235 a. e. |
| Aphelion | 446,521,000 km (2.9842 AU) | 49.31 a. e. | 51.475447 a. e. | 52.821736 a. e. | 97.651 a. e. | 1006,543776 |
| opening date | January 1, 1801 | February 18 | December 28, 2004 | March 31, 2005 | January 5, 2005 | November 14, 2003 |
| Discovered | Piazzi, Giuseppe | Clyde | Michael Brown, Jose Luis Ortiz |
Michael Brown, Chadwick Trujillo, Rabinowitz |
Michael Brown, Chadwick Trujillo, David Rabinowitz |
M. Brown, Ch. Trujillo, D. Rabinovich |
| Absolute stellar magnitude |
3.36 ± 0.02 | 0.02 m | −0,44 | -1,17+0,06 | ||
| Visible starry magnitude |
6.7 to 9.32 | >13,65 | 17,3m | 16,7 | 18,7 | |
| Albedo | 0.090 ± 0.0033 | 0.4-0.6 (Bond), 0.5-0.7 (geom.) | 0,84 +0,1 | 0.77 ± 0.030.782 +0.103 −0.086 | 0,96+0,09 | 0.32 ± 0.06 |
* Value compared to Earth.
From this list, only Pluto was “demoted”, becoming a dwarf planet and losing the status of a planet, and the rest, on the contrary, were “elevated”, ceasing to be just one of the asteroids.
Other candidates
Several dozen bodies are already known that could potentially qualify as dwarf planets.
The status of Charon, which is now regarded as a satellite of Pluto, remains inconclusive, since there is currently no precise definition of the delimitation of planets with a satellite from binary planetary systems. A draft resolution published by the IAU indicates that Charon can be considered a planet because:
Charon itself meets the size and shape criteria for planet status (in terms of the latest resolution, for dwarf planet status).
| Name | Category | Diameter | Weight |
|---|---|---|---|
| Cubivano in the Kuiper Belt | 400-800 km | unknown | |
| Scattered Disc Object | ~ 1535 km | unknown | |
| Cubivano in the Kuiper Belt | 1074-1170 km | 1.0-2.6 10 21 kg | |
| Cubivano in the Kuiper Belt | ~ 934 km | unknown | |
| Pluto in the Kuiper Belt | 917-946 km | 6.2-7.0 10 20 kg | |
| Cubivano in the Kuiper Belt | ~ 921 km | 4.5 10 20 | |
| Scattered Disc Object | ~ 733 km | unknown | |
| Cubivano in the Kuiper Belt | 722 km | ~ 5.9 10 20 kg | |
| Cubivano in the Kuiper Belt | 681-910 km | ~ 7.9 10 20 kg | |
| Pluto in the Kuiper Belt | ~ 650 km | 5.8 10 20 | |
| Cubivano in the Kuiper Belt | 626-850 km | ~ 4.1 10 20 kg | |
| Cubivano in the Kuiper Belt | 550-1240 km | unknown | |
| (Kuiper belt) | 609-730 km | unknown | |
| 2004 GV 9 | Cubivano in the Kuiper Belt | ~ 677 km | unknown |
| 2002 TC 302 | Scattered Disc Object | 590-1145 km | 1.5 · 10 21 |
| 2003 AZ 84 | Pluto in the Kuiper Belt | 573-727 km | unknown |
| 2004 XA 192 | Cubivano in the Kuiper Belt | 420-940 km | unknown |
| 2010 RE 64 | Cubivano in the Kuiper Belt | 380-860 km | unknown |
| 2010 RF 43 | Cubivano in the Kuiper Belt | ~ 613 km | unknown |
| Chaos | Cubivano in the Kuiper Belt | ~ 600 km | unknown |
| 2007 UK 126 | Scattered Disc Object | ~ 600 km | unknown |
| 2003 UZ 413 | Cubivano in the Kuiper Belt | ~ 591 km | unknown |
| 2006 QH 181 | Scattered Disc Object | 460-1030 km | unknown |
| 2010 EK 139 | Scattered Disc Object | 470-1000 km | unknown |
| 2010 KZ 39 | Scattered Disc Object | 440-980 km | unknown |
| 2001 UR 163 | Scattered Disc Object | ~ 636 km | unknown |
| 2010 FX 86 | Scattered Disc Object | ~ 598 km | unknown |
| 2013 FZ 27 | Scattered Disc Object | ~ 595 km | unknown |
| 2012 VP 113 | Scattered Disc Object | ~ 595 km | unknown |
| 2008 ST 291 | Scattered Disc Object | ~ 583 km | unknown |
| 2005 RM 43 | Scattered Disc Object | ~ 580 km | unknown |
| 1996 TL 66 | Scattered Disc Object | ~ 575 km | 2 10 20 |
| 2004 XR 190 Buffy | Scattered Disc Object | 425-850 km | 0.6-4.8 10 20 |
| 2004 NT 33 | Cubivano in the Kuiper Belt | 423-580 km | unknown |
| 2004 UM 33 | Cubivano in the Kuiper Belt | 340-770 km | unknown |
| 2002 XW 93 | Scattered Disc Object | 565-584 km | unknown |
| 2004 TY 364 | Cubivano in the Kuiper Belt | ~ 554 km | unknown |
| 2002 XV 93 | Pluto in the Kuiper Belt | ~ 549 km | unknown |
The status of Charon, which is now regarded as a satellite of Pluto, remains inconclusive, since there is currently no precise definition of the delimitation of planets with a satellite from binary planetary systems. A draft resolution (5) published by the IAU indicates that Charon can be considered a planet because:
- Charon itself meets the size and shape criteria for dwarf planet status.
- Charon, due to its large mass compared to Pluto, orbits Pluto around a common center of mass located in space between Pluto and Charon, and not around a point located inside Pluto.
This definition, however, is not in the final decision of the IAU. It is also unknown if it will appear in the future. If such a definition is approved, Charon will be considered a dwarf (double) planet. To resolve this issue as soon as possible, the adoption of an additional criterion as an additional criterion is being discussed - tidal interlocking or synchronous rotation of both components of the binary system.
In addition to Charon and all the other candidate trans-Neptunian objects, three large objects in the asteroid belt (Vesta, Pallas and Hygea) would have to be classified as dwarf planets if it turns out that their shape is determined by hydrostatic equilibrium. To date, this has not been convincingly proven.
The size and mass of dwarf planets
The lower and upper limits for the size and mass of dwarf planets are not specified in the IAU solution. There are no strict upper bounds, and an object larger or more massive than Mercury with an unrefined orbital vicinity could be classified as a dwarf planet.
The lower limit is determined by the concept of a hydrostatically equilibrium shape, but the size and mass of an object that has reached this shape is unknown. Empirical observations suggest that they can vary greatly depending on the composition and history of the object. The original source of the preliminary MAC decision determining the hydrostatic equilibrium shape applies “to objects with a mass of more than 5 · 1020 kg and a diameter of more than 800 km”, but this was not included in the final decision 5A, which was approved.
According to some astronomers, the new definition means the addition of up to 45 new dwarf planets.
>- celestial bodies of the solar system: characteristics, features, history of Pluto, definition, requirements for planets, list and candidates.
Term dwarf planet officially appeared in 2006, when planets the size of Pluto and larger were found outside the orbit of Neptune. Since then, many bodies in the solar system have been called dwarf planets.
In addition, the concept has generated a lot of controversy, especially regarding the status and nature of Pluto. Now the IAU recognizes the existence of 5 dwarf planets, and about two hundred are awaiting confirmation. Let's see what the characteristics of dwarf planets look like.
Definition of dwarf planets
Dwarf planet is a celestial object that:
- revolves around the sun;
- has enough mass to become almost round;
- but cannot clear its orbital path.
In short, this is the name for any object with planetary massiveness, but not a protruding planet or moon. But the body must revolve around the sun and have a spherical shape. Below is a list of dwarf planets, where their features, descriptions and photos are indicated.
Potential dwarf planets:
The size and mass of dwarf planets
For a body to acquire a rounded shape, it must have enough mass that resists its own gravity. The internal pressure then forms the surface layer, ensuring plasticity to fill the elevations and depressions. This does not happen with asteroids.
For celestial bodies with a diameter of a couple of kilometers, the most significant force is gravity, so they stretch out in the form of a potato. Than larger object, the higher the level of internal pressure until it reaches the point of internal balance. Admire the table of the main characteristics of dwarf planets, which includes a description of the orbit.
| Name | Ceres | Pluto | Haumea | Makemake | Eris |
|---|---|---|---|---|---|
| CMP number | 1 | 134340 | 136108 | 136472 | 136199 |
| Solar system region | Asteroid belt | Kuiper Belt | Kuiper Belt | Kuiper Belt | Scattered disc |
| Dimensions (km) | 975 × 909 | 2306 ± 20 | 1960 × 1518 × 996 | 1500 × 1420 | 2326 ± 12 |
| Weight in kg. Relative to Earth |
9.5 10 20 0,00016 |
1.305 10 22 0,0022 |
4.2 10 21 0,0007 |
? | ~ 1.67 10 22 0,0028 |
| Average equatorial radius the same in km |
0,0738 471 |
0,180 1148,07 |
~750 | ? | 0,19 ~1300 |
| Volume * | 0,0032 | 0,053 | 0,013 | 0,013 | 0,068 |
| Density (g / m³) | 2,08 | 2,0 | 2.6–3.3 | > 1.4 | 2,5 |
| Acceleration of gravity at the equator (m / s²) | 0,27 | 0,60 | 0.44 | ? | ≈ 0.8 |
| First space velocity (km / s) | 0,51 | 1,2 | 0.84 | ? | 1.3 |
| Rotation period (days) | 0,3781 | −6.38718 (retrograde) | 0.16 | 0.32 | ≈ 1 (0.75–1.4) |
| Orbital radius (a.u.) | 2,5-2,9 | 29,66-49,30 | 43.13 | 45.79 | 67.67 |
| Circulation period (years) | 4,599 | 248,09 | 283.28 | 309.9 | 557 |
| Average orbital velocity (km / s) | 17,882 | 4,666 | ? | 4.419 | 3,437 |
| Eccentricity | 0,080 | 0,24880766 | 0.195 | 0.159 | 0,44177 |
| Orbit tilt | 10.587 ° | 17.14175 ° | 28.22 ° | 28.96 ° | 44.187 ° |
| Inclination of the equatorial plane to the orbital plane | 4 ° | 119.61 ° | ? | ? | ? |
| Average surface temperature | 167 C | 44 C | 32 ± 3K | ≈ 30 K | ≈ 42 K |
| Number of known satellites | 0 | 5 | 2 | 0 | 1 |
| opening date | 01.01.1801 | 18.02.1930 | 28.12.2004 | 31.03.2005 | 5.01.2005 |
But on appearance small bodies of the solar system can also be influenced by the rotation of the axis. If it is not there, then we get a sphere. The higher the speed, the more noticeable the level of flattening. As a result, the object goes to extremes, like Haumea, which is twice as long along the main axis. Tidal forces close objects, forcing them to show only one side. This is seen in the Pluto-Charon connection.
The IAU did not provide upper and lower bounds for the mass of dwarf planets. But the lower one is displayed as the point that allows you to achieve hydrostatic balance. Size and weight are based on composition and heat history.
For example, silicate asteroids reach balance with a diameter of 600 km and a mass of 3.4 x 10 20 kg. If the object has less hard water ice, then the limit will be 320 km and 10 19 kg. It turns out that there is no standard for size or weight. Therefore, the basis is still form.
Orbital dominance of dwarf planets
Many scientists insisted that the ability to clear the space around itself should be added to the hydrostatic balance. In general, this is the ability of the planets to eliminate smaller bodies next to them, attracting or repelling them. The dwarfs simply do not have enough mass.
To define this, Alan Stern and Harold Levison introduced a parameter, a lambda. Scientists like Stephen Soter use it to separate dwarf planets from ordinary ones. He also put forward a parameter - the planetary discriminant (μ), determined by dividing the mass of a body by the mass of other objects with which it shares an orbit.
Dwarf planets and pretenders
The list of dwarf planets in the solar system includes Pluto, Makemake, Eris, Haumea and Ceres. Only the first and the last are not controversial. The IAU determined that among trans-Neptunian objects (TNOs) they become dwarf only with a diameter of 838 km and brighter 1. The lower diagram shows a comparison of the sizes of dwarf planets.
Among the contenders: Orc, 2002 MS4, Actea, Kvavar, 2007 OR10 and Sedna. They all reside in the Kuiper belt or the Scattered Disc. Sedna stands out, which stands in a separate class. It is believed that there may be 40 more known objects that should be categorized as dwarf planets. But there are more than two hundred more in the Kuiper belt, and the total number is capable of exceeding 1000.
Dwarf planet controversy
When the IAS adopted the new criteria, many scientists disagreed and a controversy ensued. Mike Brown (who discovered Eris) agreed to the new rules and the reduction of the official number of planets to 8. But Alan Stern came out with serious criticism.
He said that Mars, Jupiter, Neptune and Earth also did not completely clear the space around them. With our planet, another 10,000 near-Earth asteroids revolve around the Sun, and Jupiter has 100,000 Trojans. Therefore, Stern stubbornly considered Pluto a planet, and Ceres and Eris as complementary.
There are also problems for the classification of exoplanets. We can distinguish characteristics only indirectly, so we do not know if the orbit has cleared. Because of this, criteria appeared about minimum mass and size.
The vast majority of people are unaware that Pluto is now a dwarf planet in the solar system. If you don't know, there are now several of them. Of the five officially recognized, Pluto is not even the largest. There are many interesting facts about them, which can be found below.
This group of celestial bodies still remains the least studied due to their distance from the center of our system, but thanks to the constant development of technology, astronomers are constantly filling the gaps in their knowledge. The years 2003-2005 were quite fruitful for the discoveries. Modern technologies allows you to see even the most distant object.
Pluto
One of the smallest objects in the solar system, with a radius of only 1153 km. The orbital period around the Sun is 90,613 days (about 248 years), and the revolution around its axis takes 6.4 Earth days. For several decades since its discovery in 1930, it was considered the ninth planet, until in 2006 astronomers came to the conclusion that it should still be ranked among the dwarf planets in the Kuiper belt, which got its name after the discovery of several similar objects in 2005.
At the moment there are 5 known companions accompanying him - the largest of them is Kerber, Nikta, Styx and Hydra. The orbit of this dwarf planet is elliptical, elongated quite strongly .
Only a few years ago, scientists were able to measure the temperature on the surface of this celestial body. July 14, 2015 spacecraft New Horizons flew close to Pluto and provided a wealth of data and photographs about it.
Haumea
The fastest-rotating of all the planets known to date in our system - one revolution around its own axis takes only 4 hours, while a complete orbiting around the Sun takes 102,937 days (almost 282 years). One of the smallest objects, the average radius is only 718 km, while, unlike other celestial bodies, it has an irregular, as it were, flattened shape. At the same time, there are also 2 satellites - Hiiaka and Namaka.
Makemake
The size of the third largest is still not known for sure. It is assumed that the average radius is approximately 740 with an accuracy of 17 km. But the length of the year on it was determined quite accurately - 111867 days (which is approximately equal to 306 years). No satellites were found in its orbit.
Eris
One of the largest objects in the Kuiper belt is only slightly larger than Pluto - 1163 km. A revolution around the Sun takes 205,029 days (slightly more than 561 years).
The scientists who discovered it in 2005 were initially sure that they had discovered the 10th planet. solar system, but later it was recognized as a dwarf planet.
The discovery of this celestial body, one might say, marked the beginning of a new era for astronomy, since it was the fact of its discovery that initiated numerous disputes about the status of Pluto.
Ceres
It is noteworthy that until recently it was in the category of asteroids and ranked first among them in size. The length of a year, compared to other distant dwarf planets, is a laughable 4.6 years.
In comparison with others, its diameter is not so impressive and is 975 × 909 km. The period of rotation around the axis has a duration of about 0.3781 days. No satellites were found.
Classification
They have their own classification, which does not exist very much and it can be revised in the future based on new scientific discoveries.
Definition of the concept of dwarf planets according to international standards
The International Astronomical Union (IAU) has given a definition of space objects that will be called dwarfs. So planets are considered dwarf if they have the following signs:
- The object revolves around the sun;
- The mass of the object is sufficient to become almost round;
- The object cannot, by its gravity, clear its path on its own.
The main differences between the dwarf and the terrestrial group of planets
The difference between these planets from Terrestrial group lies in the inability of a space object to clear a path in front of itself, that is, others, such as or Mars, can, with their mass, clear a path in front of them in their orbit. Unlike large ones, these planets, as a rule, intersect with their orbits the places of accumulation of other cosmic bodies, for example, the Kuiper Belt.
To date, astronomers have managed to detect and classify five such objects:
- Pluto (the well-known planet, which at the IOC meeting in 2006, retrained from a planet to a dwarf one).
- Ceres Is a dwarf planet between Mars and Jupiter in the asteroid belt.
- Makemake - little studied, the third largest dwarf planet in front of the solar system.
- Haumea - unusual for very fast rotation around its axis.
- Eris - in terms of mass, it is the second dwarf planet after Pluto, although it is possible that the first data is being refined.
However, according to some scientists, it can contain about 100 or more small dwarf planets, they just haven't been found yet.
The International Astronomical Union designated the planets beyond the orbit of Neptune as "Plutoids".
So it is believed that Eris, which revolves around the Sun far beyond the orbit of Neptune, becomes rogue, and Ceres from the Asteroid Belt becomes a dwarf planet.
Table of dwarf planets with astronomical characteristics
| Dwarf planets | ||
| Location | Asteroid belt | |
| Dimensions (km) | 975 × 909 | |
| Weight in kg. Relative to Earth | 9.5 10 20 0,00016 |
|
| 0,0738 471 |
||
| 0,51 | ||
| Rotation period (days) | 0,3781 | |
| 0 | ||
| opening date | 01.01.1801 | |
| Pluto | Location | Kuiper Belt |
| Dimensions (km) | 2306 ± 20 | |
| Weight in kg. Relative to Earth | 1.305 10 22 0,0022 |
|
| Average equatorial radius in km | 0,180 1148,07 |
|
| First space velocity (km / s) | 1,2 | |
| Rotation period (days) | −6.38718 (retrograde) | |
| Number of known satellites | 5 | |
| opening date | 18.02.1930 | |
| Makemake | Location | Kuiper Belt |
| Dimensions (km) | 1500 × 1420 | |
| Weight in kg. Relative to Earth | ? | |
| Average equatorial radius in km | ? | |
| First space velocity (km / s) | ? | |
| Rotation period (days) | 0.32 | |
| Number of known satellites | 1 | |
| opening date | 31.03.2005 | |
| Eris | Location | Scattered disc |
| Dimensions (km) | 2326 ± 12 | |
| Weight in kg. Relative to Earth | ~ 1.67 1022 0,0028 |
|
| Average equatorial radius in km | 0,19 ~1300 |
|
| First space velocity (km / s) | 1.3 | |
| Rotation period (days) | ≈ 1 (0.75–1.4) | |
| Number of known satellites | 1 | |
| opening date | 5.01.2005 | |
| Haumea | Location | Kuiper Belt |
| Dimensions (km) | 1960 × 1518 × 996 | |
| Weight in kg. Relative to Earth | 4.2 1021 0,0007 |
|
| Average equatorial radius in km | ~750 | |
| First space velocity (km / s) | 0.84 | |
| Rotation period (days) | 0.16 | |
| Number of known satellites | 2 | |
| opening date | 28.12.2004 | |
| Sedna | Location | Oort Cloud |
| Dimensions (km) | 995 ± 80 | |
| Weight in kg. Relative to Earth | 8.3 1020 - 7.0 1021 | |
| Average equatorial radius in km | ? | |
| First space velocity (km / s) | ? | |
| Rotation period (days) | 0.42 d (10 h) | |
| Number of known satellites | 0 | |
| opening date | 14.11.2003 | |
Other candidates for the title of dwarf planet
Thanks to modern means of detection, scientists have discovered several dozen large space bodies that can be attributed and qualified to the "Plutoids" planets. The table below shows planetoids with an approximate diameter of up to 600 km. Moreover, the first 6 objects are likely to become the main candidates.
| Name | Category | Diameter | Weight |
|---|---|---|---|
| 2015 KH 162 | Cubivano in the Kuiper Belt | 400-800 km | unknown |
| 2007 OR 10 | Scattered Disc Object | ~ 1535 km | unknown |
| Quavar | Cubivano in the Kuiper Belt | 1074-1170 km | 1.0-2.6 10 21 kg |
| 2002 MS 4 | Cubivano in the Kuiper Belt | ~ 934 km | unknown |
| Orc | Pluto in the Kuiper Belt | 917-946 km | 6.2-7.0 10 20 kg |
| Salacia | Cubivano in the Kuiper Belt | ~ 921 km | 4.5 10 20 |
| 2013 FY 27 | Scattered Disc Object | ~ 733 km | unknown |
| Varuna | Cubivano in the Kuiper Belt | 722 km | ~ 5.9 10 20 kg |
| 2002 UX 25 | Cubivano in the Kuiper Belt | 681-910 km | ~ 7.9 10 20 kg |
| Ixion | Pluto in the Kuiper Belt | ~ 650 km | 5.8 10 20 |
| 2002 AW 197 | Cubivano in the Kuiper Belt | 626-850 km | ~ 4.1 10 20 kg |
| 2005 UQ 513 | Cubivano in the Kuiper Belt | 550-1240 km | unknown |
| Warda | Cubivano in the Kuiper Belt | 500-1130 km | ~ 6.1 10 20 kg |
| 2005 RN 43 | Cubivano in the Kuiper Belt | ~ 730 km | unknown |
| 2003 VS 2 | Pluto in the Kuiper Belt | ~ 725 km | unknown |
| 2007 JJ 43 | Unknown (Kuiper belt) | 609-730 km | unknown |
| 2004 GV 9 | Cubivano in the Kuiper Belt | ~ 677 km | unknown |
| 2002 TC 302 | Scattered Disc Object | 590-1145 km | 1.5 · 10 21 |
| 2003 AZ 84 | Pluto in the Kuiper Belt | 573-727 km | unknown |
| 2004 XA 192 | Cubivano in the Kuiper Belt | 420-940 km | unknown |
| 2010 RE 64 | Cubivano in the Kuiper Belt | 380-860 km | unknown |
| 2010 RF 43 | Cubivano in the Kuiper Belt | ~ 613 km | unknown |
| Chaos | Cubivano in the Kuiper Belt | ~ 600 km | unknown |
| 2007 UK 126 | Scattered Disc Object | ~ 600 km | unknown |
| 2003 UZ 413 | Cubivano in the Kuiper Belt | ~ 591 km | unknown |
| 2006 QH 181 | Scattered Disc Object | 460-1030 km | unknown |
| 2010 EK 139 | Scattered Disc Object | 470-1000 km | unknown |
| 2010 KZ 39 | Scattered Disc Object | 440-980 km | unknown |
| 2001 UR 163 | Scattered Disc Object | ~ 636 km | unknown |
| 2010 FX 86 | Scattered Disc Object | ~ 598 km | unknown |
| 2013 FZ 27 | Scattered Disc Object | ~ 595 km | unknown |
| 2012 VP 113 | Scattered Disc Object | ~ 595 km | unknown |
| 2008 ST 291 | Scattered Disc Object | ~ 583 km | unknown |
| 2005 RM 43 | Scattered Disc Object | ~ 580 km | unknown |
| 1996 TL 66 | Scattered Disc Object | ~ 575 km | 2 10 20 |
| 2004 XR 190 Buffy | Scattered Disc Object | 425-850 km | 0.6-4.8 10 20 |
| 2004 NT 33 | Cubivano in the Kuiper Belt | 423-580 km | unknown |
| 2004 UM 33 | Cubivano in the Kuiper Belt | 340-770 km | unknown |
| 2002 XW 93 | Scattered Disc Object | 565-584 km | unknown |
| 2004 TY 364 | Cubivano in the Kuiper Belt | ~ 554 km | unknown |
| 2002 XV 93 | Pluto in the Kuiper Belt | ~ 549 km | unknown |