Uranus, not far from Earth in the darkest region of the solar system’s reach, is not alone. With it is a spell of the moon – 27, precisely. Far and obscure, this moon is difficult to study, but astronomers have made accidental discoveries while observing Uranus.
According to infrared images of the five main moons of Uranus, their formation is closer to dwarf planets such as the icy crusted compact, rocky objects – Pluto and Haumea, than the more furry formation of the smaller Uranian moon.
Uranus orbits the Sun at an average distance of 20 times that of the Earth. We haven’t sent many spacecraft yet – only NASA’s Voyager 2 spacecraft has had a ga encounter with Uranus, moving to and from the edge of the solar system in 1986.
Aside from those Voyager 2 observations, our study of the planet and its satellites depends on telescopes closer to home – on Earth and around Earth orbit. That makes the moon too challenging to see; They are much smaller and reflect less sunlight than Uranus, so they reach the point of invisibility.
The moon, which is 500 to 7,400 times leaner, is at such a small distance from Uranus that it merges into similar luminous artifacts, said Gober Martin, an astronomer at Hungary’s Concoli Observatory. “Only the bright moon, Titania and Oberon, are a little stand out from the surrounding glitter.”
Which conducted a random probe of five moons by the European Space Agency’s Herschel Space Observatory in operation between 2009 and 2013 to study galaxies in infrared radiation, which is very pleasing.
“Indeed, we conducted observations to measure the effect of very bright infrared sources, such as Uranus, on my detector,” said Ulrich Klass, an astronomer at the Max Planck Institute for Astronomy in Germany.
“We discovered the moon just by chance as extra nodes in the planet’s brightest sign.”
Left to right: Miranda, Ariel, Umbriel, Titania and Oberon, images by Voyager 2 in 1986. (NASA / JPL / MPIA)
The five main moons of Uranus, in descending order of size, are Titania, Oberon, Umbriel, Ariel, and Miranda. Voyager 2 reveals that all five have a spherical shape indicating that they have achieved hydrostatic equilibrium – that is, a mass sufficient to develop a symmetrical, spherical shape under their own gravity. And they seem to be made of rock and ice.
It is not uncommon for objects to be far from the sun. Even when heated by the sun, the temperature of Uranus and its lunar surface is only about 60 to 80 Kelvin (-213 to -193 સે C or -350 to -315 સપાટી F). Pluto is very rocky and icy.
But it’s important how the rock and ice are put together. The small, irregular, asymmetrical lunar eccentric orbits of Uranus indicate that they have the same structure as the rocky body in the Kuiper belt outside of Neptune, a trans-Neptuneian object. These are just loosely bound together, and fairly small.
“This will also correspond to speculation about the origin of the irregular moon,” said Thomas Müller, an astrophysicist at the Max Planck Institute for Extraterrestrial Physics in Germany. “Because of their chaotic orbit, it is believed that they were captured by the Uranian system at a later date.”
In general, the five main moons, which orbit the Uranus equator, will be difficult to see. Uranus has a curious approach, indicated by its orbital plane around the Sun, so its equator often stays in the shadows.
(T. mlerr [HdA]/. H. Detrey et al. / MPIA)
During the team’s observations of Uranus between 2010 and 2012, however, the equator was in terms of telescopes and sunlight. And when the team excluded Uranus from the data using a specially developed algorithm, something wonderful emerged.
“When the four moons clearly appeared on the images, we were all amazed, and we found Miranda, the smallest and farthest from the five largest Uranian moons,” said H. H. Detrey, an astronomer at the Max Planck Institute for Astronomy. “
The team was able to measure how heat from the sun was retained in the lunar surface, as that surface rotates at night. These surfaces, it turns out, retain heat fairly well, cooling relatively slowly.
It had a familiar heat retention and cooling profile – the closest matches are dwarf planets like Pluto and Haumea, with their ga ense rocky bodies and ice-encrusted surfaces. This suggests that Titania, Oberon, Umbriel, Ariel, and Miranda were built similarly – although the exact chemical composition of the rock and the ice on it has not yet been determined.
This discovery could mean that sending investigations to ice giants could help them learn more about distant objects and objects, even in the space of the Cooper Belt obscurity. But it also shows the value of appearing right under our noses.
“The results show that we don’t always need extended planetary space missions to gain new insights into the solar system,” said Hendrik Linz, an astronomer at the Max Planck Institute for Astronomy.
“In addition, the new algorithm could be applied to more observations that have been collected in large numbers in the electronic data archive of the European Space Agency ESA. Who knows what we still wonder there?”
Research has been published in Astronomy and Astrophysics.
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