wonderful image of Neptune’s rings

The rings of Neptune, flown over by Voyager 2

Neptune’s rings were first photographed in 1989, when the Voyager 2 probe passed closer to the ice giant. Voyager 2, launched on August 20, 1977, is to date the only spacecraft to have approached the planet Neptune.

The existence of a system of rings revolving around Neptune has been mentioned as far back as 1846 when British astronomer William Lassel thought he saw at least one ring around the planet. This scientist was also the discoverer of Triton, Neptune’s largest moon. In 1968 one of the planet’s rings was revealed thanks to the stellar occultation technique which is used to detect objects in the solar system that are too small, too faint or too distant. The technique consists of capturing the image of the object as it passes in front of a star. The stellar luminous flux is then analyzed.

In 1984, the first tangible evidence of the existence of Neptune’s rings came during a stellar occultation observation program at ESO’s La Silla Observatory in northern Chile. Right now, astronomers are certain of the presence of something around Neptune that they consider incomplete arches.

The Voyager 2 probe has definitively proved the existence of the rings. Subsequently, the Hubble Space Telescope also contributed to this discovery.

Currently, astronomers know of the existence of five rings orbiting Neptune. Three of them have a width that does not exceed 100 km and the other two have a width between 2000 and 5000 km. Neptune’s rings are mostly made of very fine dust.

(Also Read: James Webb: See Behind the Scenes of a Historical Photo!)

The rings of Neptune and the seven moons

In this version of the Neptune image of Webb’s NIRCam (Near-Infrared Camera), the visible moons of the planet are labeled. Neptune has 14 known satellites and seven of them are visible in this image. Triton, the bright spot in the upper left of this image, far eclipses Neptune because the planet’s atmosphere is obscured by the methane absorption wavelengths captured by Webb. Triton reflects on average 70 percent of the sunlight that hits it. It is suspected that Triton, which orbits Neptune in a backward orbit, was originally a Kuiper belt object captured gravitationally by Neptune.

This image shows Neptune’s rings and seven moons out of fourteen. Source: NASA / ESA / CSA and STScI

This photo was taken with James Webb’s NIRcam instrument which works in the near infrared between 0.6 and 5 microns of wavelength. In visible light photographs, the planet appears as a blue dot due to its methane atmosphere. The infrared image allows us to observe a planet with a milky disc with bright spots and streaks on the surface corresponding to the methane ice clouds present at high altitude on this frozen planet. The south pole of the planet is surrounded by a vortex of high-altitude clouds.

In this shot, a line of light appears at the planet’s equator. According to astronomers, this is the hallmark of the atmospheric circulation that powers the winds and storms taking place on Neptune. Scientists know that Neptune is a planet with a capricious climate and that the winds raging on its surface can reach more than 1600 km / h!

The planet Neptune is surrounded by fourteen natural satellites, seven of which are clearly visible in the image. Proteus is clearly visible on the right of the image and is not hidden by Neptune’s rings. The other visible moons are Larissa, Despina, Thalassa, Na├»ade, Galatea and Triton in the upper left which looks like a star because it is so bright.

This image allows us to observe four of Neptune’s five rings with great precision. The outermost ring was called Adams and the other three are Lassell, Le Verrier and Galle. The fifth called Arago, the closest to Neptune, is not visible.

(Read also: 3 discoveries about Neptune and its moons)

Neptune, the eighth planet in the solar system

In the solar system, the giant Saturn remains the planet whose rings are the most visible. However, she is not the only one to have it. James Webb has just photographed Neptune’s rings, but planets like Uranus and Jupiter also have rings. However, they are difficult to see because very often they consist of ice dust that reflects little sunlight. Saturn’s rings reflect at least 60% of sunlight because they are made up of large particles of water ice that can reach several meters in size.

The planet Neptune, which has just unveiled its ring system via James Webb, is in an almost circular orbit 4.5 billion kilometers from the Sun and takes 165 years to make a complete revolution of the Sun.

It is composed largely of helium and hydrogen, the rest of ice water, ammonia and methane that form its mantle. Neptune also has a small rocky core. The planet’s atmosphere, which contains about 80% hydrogen and 19% helium, is 8000 km thick and also contains traces of methane which gives it its blue color, as well as some ammonia. of ethane and acetylene.

These unprecedented images of the planet Neptune show the incredible feats of which the James Webb Space Telescope is capable. It allows us not only to observe the deep space in the universe, but also the space closest to us within our solar system.

(Read also: What happens to the James Webb Telescope 1.5 million kilometers from Earth?)


“The new Webb image captures the clearest view of Neptune’s rings in decades”, Webb space telescopeSeptember 21, 2022, https://webbtelescope.org/contents/news-releases/2022/news-2022-046

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