氷の巨星天王星の Webb の見事な新しいビューでまばゆいリングと驚くほどダイナミックな雰囲気

クレジット: 科学: NASA、ESA、CSA、STScI、画像処理: Joseph DiPasquale (STScI)

ウェッブの赤外線画像は、惑星の劇的な輪とダイナミックな大気を強調しています

宇宙[{” attribute=””>Uranus is an oddball in our solar system, tilted on its side as it orbits the sun, causing extreme seasons. While the planet’s atmosphere appeared nearly featureless when visited by the Voyager 2 spacecraft in 1986, subsequent observations from the ground and in space have shown turbulent storms.

NASA’s James Webb Space Telescope recently observed Uranus, and the resulting image highlights a complex system of rings as well as a bright polar cap and likely storm clouds.

This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) on February 6, 2023, reveals stunning views of the planet’s rings. The planet displays a blue hue in this representative-color image, made by combining data from two filters (F140M, F300M) at 1.4 and 3.0 microns, which are shown here as blue and orange, respectively. Credit: Science: NASA, ESA, CSA, STScI, Image Processing: Joseph DePasquale (STScI)

Webb Space Telescope Scores Another Ringed World with New Image of Uranus

Following in the footsteps of the Neptune image released in 2022, NASA’s James Webb Space Telescope has taken a stunning image of the solar system’s other ice giant, the planet Uranus. The new image features dramatic rings as well as bright features in the planet’s atmosphere. The Webb data demonstrates the observatory’s unprecedented sensitivity for the faintest dusty rings, which have only ever been imaged by two other facilities: the Voyager 2 spacecraft as it flew past the planet in 1986, and the Keck Observatory with advanced adaptive optics.

The seventh planet from the Sun, Uranus is unique: It rotates on its side, at roughly a 90-degree angle from the plane of its orbit. This causes extreme seasons since the planet’s poles experience many years of constant sunlight followed by an equal number of years of complete darkness. (Uranus takes 84 years to orbit the Sun.) Currently, it is late spring for the northern pole, which is visible here; Uranus’ northern summer will be in 2028. In contrast, when Voyager 2 visited Uranus it was summer at the south pole. The south pole is now on the ‘dark side’ of the planet, out of view and facing the darkness of space.

This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) on February 6, 2023, reveals stunning views of the planet’s rings. On the right side of the planet, there’s an area of brightening at the pole facing the Sun, known as a polar cap. This polar cap is unique to Uranus because it is the only planet in the solar system tilted on its side, which causes its extreme seasons. A new aspect of the polar cap revealed by Webb is a subtle brightening near the Uranian north pole. At the edge of the polar cap lies a bright cloud as well as a few fainter extended features just northward of the cap’s edge, and a second very bright cloud is seen at the planet’s left limb. Such clouds are typical for Uranus in infrared wavelengths, and likely are connected to storm activity. Credit: Science: NASA, ESA, CSA, STScI, Image Processing: Joseph DePasquale (STScI)

This infrared image from Webb’s Near-Infrared Camera (NIRCam) combines data from two filters at 1.4 and 3.0 microns, which are shown here in blue and orange, respectively. The planet displays a blue hue in the resulting representative-color image.

When Voyager 2 looked at Uranus, its camera showed an almost featureless blue-green ball in visible wavelengths. With the infrared wavelengths and extra sensitivity of Webb we see more detail, showing how dynamic the atmosphere of Uranus really is.

This wider view of the Uranian system with Webb’s NIRCam instrument features the planet Uranus as well as six of its 27 known moons (most of which are too small and faint to be seen in this short exposure). A handful of background objects, including many galaxies, are also seen. Credit: Science: NASA, ESA, CSA, STScI, Image Processing: Joseph DePasquale (STScI)

On the right side of the planet, there’s an area of brightening at the pole facing the Sun, known as a polar cap. This polar cap is unique to Uranus – it seems to appear when the pole enters direct sunlight in the summer and vanish in the fall; these Webb data will help scientists understand the currently mysterious mechanism. Webb revealed a surprising aspect of the polar cap: a subtle enhanced brightening at the center of the cap. The sensitivity and longer wavelengths of Webb’s NIRCam may be why we can see this enhanced Uranus polar feature when it has not been seen as clearly with other powerful telescopes like the Hubble Space Telescope and Keck Observatory.

At the edge of the polar cap lies a bright cloud as well as a few fainter extended features just beyond the cap’s edge, and a second very bright cloud is seen at the planet’s left limb. Such clouds are typical for Uranus in infrared wavelengths, and likely are connected to storm activity.

This planet is characterized as an ice giant due to the chemical make-up of its interior. Most of its mass is thought to be a hot, dense fluid of “icy” materials – water, methane, and ammonia – above a small rocky core.

ジェームス ウェッブ宇宙望遠鏡は、太陽系のもう 1 つの氷の巨大惑星である天王星の驚くべき画像を捉えました。 新しい画像は、エキサイティングなリングと、惑星の大気中の明るい特徴を特徴としています。 天王星に関する Webb の新しいデータは、驚くべき感度を提供し、最も弱い塵の輪を明らかにします。 太陽から 7 番目の惑星である天王星は奇妙です。軌道面から約 90 度の角度で横向きに回転します。 これは、惑星の極が 42 年間の連続した日光と 42 年間の完全な暗闇を経験するため、異常な季節を引き起こします (天王星は太陽を周回するのに 84 年かかります)。 現在、この画像の右側にある北極の晩春です。 北の夏は2028年に天王星にあります。

天王星には 13 個の既知のリングがあり、そのうち 11 個がこの Web 画像に表示されています。 これらのリングのいくつかはウェッブと非常に明るいため、それらが接近すると、より大きなリングに融合するように見えます. 9 つは惑星のメイン リングとして分類され、2 つは、1986 年のボイジャー 2 のフライバイまで発見されなかったかすかなほこりの多いリング (惑星に最も近いゼータの拡散リングなど) です。 2 つのかすかな外側のリングが明らかになります。 ハッブルで調べる 2007 年の環状平面横断中。

ウェッブは、天王星の知られている 27 の衛星の多くも捉えました (それらのほとんどは小さすぎて、ここでは見ることができません)。 広視野画像では、最も明るい 6 つが識別されます。 これは天王星のわずか 12 分間の露出画像で、候補は 2 つしかありませんでした。 これは、この神秘的な惑星を観察するときにウェッブができることの氷山の一角にすぎません。 天王星の追加研究が現在進行中であり、Webb の科学活動の最初の年にさらに多くの研究が計画されています。

2022 年に、全米科学アカデミー、工学アカデミー、および医学アカデミーは、天王星科学を惑星科学および宇宙生物学 2023-2033 の優先事項として指定しました。 私のノードスキャン.

ジェームズ ウェッブ宇宙望遠鏡は、世界有数の宇宙科学天文台です。 私たちの太陽系の秘密を明らかにし、他の星の周りの遠い惑星を探索し、神秘的な構造と宇宙の始まりとその中での私たちの場所を調べます. このプログラムは、NASA、欧州宇宙機関 (ESA)、およびカナダ宇宙機関の間の共同作業であり、NASA が主導しています。