Thanks to ground-based telescopes, astronomers have discovered three previously unknown satellites in the space around Uranus and Neptune: one orbiting Uranus and two around Neptune. Thus, the official number of Uranus’ satellites is 28, and Neptune’s is 16.
The moons have yet to be officially named, but according to the tradition of naming both planets, the new Uranus moon will be named after Shakespeare’s works, and Neptune’s moons — in honor of the sea goddesses Nereids from Greek mythology.
«The three newly discovered satellites are the faintest ever found around these two ice giant planets using ground-based telescopes. Special image processing was required to detect such faint objects»», — says astronomer Scott Sheppard of the Carnegie Institution for Science.
In recent years, Jupiter and Saturn have dominated the race to find new moons, while Neptune and Uranus have been overlooked. The two outer icy planets are far from Earth, making it difficult for spacecraft to travel to them. They are also difficult to see with telescopes — their understanding is more limited than the other five worlds closer to Earth.
The new Uranian moon, first spotted during observations with one of the «Magellan» telescopes in November 2023, was confirmed to be present in data dating back to 2021. It has been temporarily named S/2023 U1, and it is the first new Uranian moon discovered in more than 20 years. It is about 8 km in diameter, making it the smallest of Uranus’ moons and one of the smallest known moons in the solar system. Its orbital period is 680 days.
The brightest of Neptune’s two moons, given the temporary designation S/2002 N5, was first spotted during «Magellan» observations in September 2021 and then again in October, with further observations in 2022 and 2023. Its diameter is 23 km and its orbital period is — 9 years.
The smaller of Neptune’s new moons was spotted in 2021 using the Subaru telescope. Temporarily named S/2021 N1, it measures 14 km across with an orbit of 27 years around the planet.
The newly discovered satellites suggest that Uranus and Neptune have families of outer satellites in configurations similar to Saturn (146 known satellites) and Jupiter (95 known satellites). This suggests that the formation of these satellites is similar to that of the larger planets.
New celestial bodies are part of groups of satellites that have similar orbits. S/2023 U1 is close to Caliban and Stefano. S/2002 N5 correlates with the orbits of Sao and Laomedeus, and the orbit of S/2021 N1 is similar to the orbits of Psamate and Neso.
None of the orbits are exactly the same, but the similarities suggest that each of these groups of moons may have once been a single object that was captured by planetary gravity before breaking apart. If this is the case, each group may have much smaller moons that are difficult to find. This discovery is another good reason to send probes to the outer part of the solar system.
Source: Science Alert