3 more Uranus-Neptune moons found, one of which breaks the record for smallest size: PPTVHD36

Astronomers announced the discovery of another moon of Uranus, while two more moons of Neptune have been found.

A “moon” is a satellite that almost every planet in the solar system has. In particular, exoplanets contain up to tens or hundreds of moons.

Recently, on February 23, there was big news in the astronomy industry. When the International Astronomical Union's Asteroid Center officially announced that it had “discovered three new moons” of Uranus and Neptune, including one moon of Uranus and two of Neptune.

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This would increase the number of moons of the ice giants. Uranus will have 28 additional moons, this is the first additional moon discovered for Uranus in more than 20 years, and Neptune will have a total of 16 moons.

“The three newly discovered moons are the faintest moons ever discovered around a giant planet,” said Carnegie Science's Scott Sheppard, lead author on the discovery team. “Two icy stars using ground-based telescopes… We had to use special image processing” to detect such faint objects.

As for the newly discovered Uranus moon, it is currently provisionally called S/2023 U1, and from now on it will be named according to the original rules. The names of characters appearing in the works of William Shakespeare or Alexander Pope are used in naming. As in the past there is the moon named Juliet (the female hero of Romeo and Juliet) or Oberon (the king of the fairies in A Midsummer Night's Dream), for example.

S/2023 U1 is only 8 kilometers across, making it the smallest moon in the solar system. (The smallest current moon is Mars' Deimos, which is 13 kilometers across.) It takes a total of 680 days to orbit Uranus once.

S/2023 U1 was first discovered on November 4, 2023 by Shepard using the Magellan Telescope at Las Campanas Observatory in Chile.

Sheppard followed up on his findings a month later, working with NASA's Jet Propulsion Laboratory to determine the orbit of the newly discovered moon.

Neptune's two newly discovered moons were discovered in September 2021 and are now officially known as S/2002 N5 and S/2021 N1.

S/2002 N5 is about 23 kilometers across and takes nearly nine years to orbit Neptune. It is brighter than S/2021 N1, and if you look closely you will see that its symbol is 2002, which means it has been observed since 2002 but was only recently officially confirmed.

“When the orbit of S/2002 N5 around Neptune was determined using surveys in 2021, 2022 and 2023, it was traced back to an object that had been observed near Neptune in 2003, but which had since been lost. Before it was confirmed whether that was it or not.” “It was actually orbiting Neptune,” Sheppard explained.

Meanwhile, S/2021 N1 is less bright. It makes it lighter and harder to notice. It takes an exceptionally long time to observe, as it is about 14 kilometers across and has an orbit of approximately 27 years.

Both moons will receive permanent names after the Nereids, one of Poseidon's 50 sea gods. God of the sea in Greek mythology. This is because Neptune is the Roman name for Poseidon.

The discovery of the three new moons required astronomers to take dozens of 5-minute images over a continuous period of 3 to 4 hours each night. The imaging is adjusted according to the movement of each planet before they are combined to create a deeper image

“Because the Moon moves in only a few minutes relative to the stars and galaxies, long single observations are not suitable for in-depth imaging of moving objects,” Sheppard said.

He added: “By composing these composite images, stars and galaxies and the lines of their orbital paths appear behind them. Moving objects similar to this planet are considered assets. Bring the moon out from behind the background noise in the image.”

The team of scientists also discovered that all three moons have highly elliptical orbits tilted relative to the plane of the ice giants. Which means that these moons do not form around their parent planets. But it was an object from somewhere else that was later brought together by gravity.

Compiled from Carnegie Institution for Science / Space.com website