Orion is the second-farthest dwarf planet from the Sun, located outside the orbit of Neptune. It was discovered in 2005 and is the third largest known dwarf planet.
Key facts and summaries
- It was discovered on March 31, 2005, by a team of astronomers from the Paloma Observatory, who also discovered the dwarf planet Eris.
- Its discoveries, along with those of Erus and Haemos, helped to reclassify Pluto as planetary to dwarf planets.
- This is the fourth dwarf planet to be discovered. This includes Pluto, which has been reclassified.
- Orion has a moon, a dimly lit moon, named MK 2.
- Orion is large enough and bright enough to be studied by high-end amateur telescopes.
- Orion is about one-fifth the brightness of Pluto. It is fainter than Pluto, but brighter than Eris.
- The radius of Orion is about 444 miles/715 kilometers, which is 1/9 of the radius of Earth.
- Like other dwarf planets, it passes through the Kuiper Belt.
- The day on Orion lasts about 22.5 hours.
- Orion is about 45.8 AU from the Sun and about 53.2 AU from Earth, however, these values are constantly changing, and in order to get accurate and realistic statistics, one can check its location online because Makemake is constantly being tracked.
- Orion's light takes about 7 hours and 22 minutes to reach Earth.
- It is the second farthest dwarf planet from the Sun and the third largest known dwarf planet in the Solar System.
Make facts and history
The discovery of Orion was publicly announced on July 29, 2005. Astronomer Michael M. A team led by Michael E. Brown discovered the object at the Paloma Observatory in San Diego.
For some time, when the discovery was made public, Orion received provisional designation for fiscal year 2005. Before that, however, the discovery team used the code name "Easterbunny" because the dwarf planet was discovered shortly after Easter.
July 2008,
According to the IAU's rules for classical Kuiper Belt objects, the dwarf planet is named after a deity. Ornitho is the name of the god of humanity and fertility in the myth of Rapa Nui, an indigenous people of Easter Island. Therefore, the name was chosen to preserve the object's connection to Easter.
formation
Ornithus is luckier than Ceres because it is located in the Kuiper Belt, an area beyond neptune orbit along with the other dwarf planets Erpian, Pluto, and Haumea. It is the second brightest object in the Kuiper Belt, with Pluto being the brightest.
The Kuiper Belt is a group of objects that orbit in a disk-like region outside Neptune's orbit. This distant realm is filled with thousands of tiny, icy worlds that formed in the early days of our solar system about 4.5 billion years ago.
Distance, size and quality
The radius of Orion is about 444 miles/715 kilometers, which is 1/9 of the radius of Earth. It has a diameter of about 1,430 km. Compared to nickel, it's like the size of a mustard seed. The distance from the Sun is considerable, about 45.8 AU from The Earth and about 53.2 AU from the Earth.
It's about two-thirds the size of Pluto and about three times the size of the 277-mile-long Grand Canyon. Its mass is estimated at 4 x 10²¹ kg, about 4,000,000,000 trillion kilograms, equivalent to 0.00067 Earths.
Orbit and rotation
Orion's orbital period is estimated to be about 310 years. Its orbit is far enough away from Neptune to remain stable at the edge of the solar system. It has a slightly eccentric orbit that ranges from 38.5 AU at perihelion to 52.8 AU at aphelion.
The rotation period is estimated at 22.83 hours, which is relatively long for dwarf planets, and it takes about 7.77 hours to complete a single star rotation. These statistics suggest that a day on Orion is less than 8 hours, while a year lasts about 112.897 days. One of the reasons may be attributed to the tidal acceleration of Orion's moons. Another suggestion is that Orion may have a second undiscovered moon, which could explain its unusually long rotation time.
Geology and atmosphere
Similar to Pluto, it appears red in the visible spectrum, significantly redder than the surface of Pluto. The spectral signatures of orion methane are much stronger than those of Pluto and Rhodos. The analysis showed that methane must be present in the form of large particles at least one centimeter in size.
There may be large amounts of ethane, thiols and small amounts of high-quality alkanes such as ethylene, acetylene and propane, which may be produced by the photolysis of methane irradiated by the sun. Tholins may be the cause of the red color of the visible spectrum. Some data claim that nitrogen ice levels are also very low,
The relative lack of this may be attributed to some sort of depletion of solar system age. However, even at low levels, the presence of methane ice can turn red if exposed to solar radiation for a period of time.
According to astronomer Javier Licandro and colleagues, Orion has a bright surface with an estimated albedo of 0.81, similar to Pluto.
The atmosphere of Orion remained a mystery for some time. In 2011, there was a masking between it and an 18th magnitude star, which blocked all of its light by Orion.
These results conclude that dwarf planets lack substantial atmospheres, which contradicts earlier assumptions that their atmospheres resemble Pluto's. But this can be changed by the presence of methane and possibly nitrogen. It is believed that when Orion reaches the nearest point in orbit near the Sun, it may have a transient atmosphere similar to Pluto's.
With this approach, nitrogen and other ice will sublimate, forming a fragile atmosphere of nitrogen and hydrocarbons. This would also provide an explanation for the depletion of nitrogen, which may have disappeared through the process of atmospheric escape.
satellite
Orion has a natural moon nicknamed MK 2. It was discovered in 2016 by the Hubble Space Telescope's wide-field camera 3. However, there has been speculation that it may have a second undiscovered moon, which could explain its unusually long rotation time.
MK 2 dimensions and tracks
It is estimated that MK 2 has a diameter of about 175 km, assuming an albedo of 4% and a radius of about 90 km. Its orbital period is about 12 days. It is estimated that its semi-long axis is at least 21.000 km away from Orion. The actual orbital eccentricity is unknown.
Brightness and further observation
Preliminary research suggests that MK2 has a charcoal-like reflectivity, making it a very dark object. In fact, this is quite surprising, as Orion is the second brightest known object in the Kuiper Belt, and the moons it found were about 1.300 times larger. Many things about Orion and its Moon remain to be answered, so observations continue.
Habitability of life
Temperatures on Orion are usually around -406 degrees Fahrenheit or -243 degrees Celsius. Life as we know it could not have existed in such a cold place.
Orion's future plans
Based on recent calculations of current technology, it is estimated that the mission to fly over Orion with the help of Jupiter's gravitational assistance could take about 16 years. According to the launch date of 2024 or 2036, Orion is about 52 AU away from the Sun when the spacecraft arrives.
However, there is currently no expedition set for Orion, and despite its mystery and our lack of information about it, it is certainly a strength for future exploration and continuous observation.
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