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令人難以置信的小行星精神新地圖揭示了一個古老的金屬和岩石世界

令人難以置信的小行星精神新地圖揭示了一個古老的金屬和岩石世界

小行星自組成

麻省理工學院和其他地方的天文學家繪製了小行星 Psyche 的組成圖,揭示了金屬、沙子和岩石的表面。 信用:美國國家航空航天局的截圖

小行星 Psyche 多變的表面暗示了一段動態的歷史,其中可能包括礦物噴發、小行星震動效應和缺失的岩幔。

今年晚些時候,[{” attribute=””>NASA is set to launch a probe the size of a tennis court to the asteroid belt, a region between the orbits of Psyche Spacecraft at the Asteroid Psyche (Illustration)

This illustration, updated in April 2022, depicts NASA’s Psyche spacecraft. Set to launch in August 2022, the Psyche mission will explore a metal-rich asteroid of the same name that lies in the main asteroid belt between Mars and Jupiter. The spacecraft will arrive in early 2026 and orbit the asteroid – also shown in this illustration – for nearly two years to investigate its composition. Credit: NASA/JPL-Caltech/ASU

Overall, Psyche’s surface was found to be surprisingly varied in its properties.

The new maps hint at the asteroid’s history. Its rocky regions could be vestiges of an ancient mantle — similar in composition to the rocky outermost layer of Earth, Mars, and the asteroid Vesta — or the imprint of past impacts by space rocks. Finally, craters that contain metallic material support the idea proposed by previous studies that the asteroid may have experienced early eruptions of metallic lava as its ancient core cooled.

“Psyche’s surface is very heterogeneous,” says lead author Saverio Cambioni, the Crosby Distinguished Postdoctoral Fellow in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “It’s an evolved surface, and these maps confirm that metal-rich asteroids are interesting, enigmatic worlds. It’s another reason to look forward to the Psyche mission going to the asteroid.”

Cambioni’s co-authors are Katherine de Kleer, assistant professor of planetary science and astronomy at Caltech, and Michael Shepard, professor of environmental, geographical, and geological sciences at Bloomsburg University.

Telescope Power

The surface of Psyche has been a focus of numerous previous mapping efforts. Researchers have observed the asteroid using various telescopes to measure light emitted from the asteroid at infrared wavelengths, which carry information about Psyche’s surface composition. However, these studies could not spatially resolve variations in composition over the surface.

Cambioni and his colleagues instead were able to see Psyche in finer detail, at a resolution of about 20 miles per pixel, using the combined power of the 66 radio antennas of the Atacama Large Millimeter/submillimeter Array (

在左側,這張地圖顯示了 Psyche 的表面特徵,從沙地(紫色/低)到岩石區(黃色/高)。 右邊的地圖顯示了 Psyche 上的礦物質豐度,從低(紫色)到高(黃色)。

趕上比賽

在這項新研究中,Cambioni 對 Psyche 進行了模擬,以查看哪些表面特性最能匹配並解釋測量的熱量排放。 豐富。 他模擬了小行星的旋轉並測量了小行星上的模擬材料如何散發熱量。 然後,Campione 尋找與 ALMA 測量的實際排放最匹配的模擬排放。 小行星表面材料。

“我們逐個區域運行這些模擬,直到我們能夠確定表面特性的差異,”坎皮奧內說。

該研究製作了普賽克表面特性的詳細地圖,顯示小行星的界面可能覆蓋著各種各樣的材料。 研究人員證實,普賽克的表面通常富含礦物質,但其表面的礦物質和矽酸鹽含量各不相同。

他們還發現,當小行星繞軌道運行時,位於大窪地底部的物質——可能是隕石坑——的溫度變化速度比邊緣的物質快得多。 這表明火山口底部覆蓋著細粒物質的“池”,就像地面上的沙子一樣,升溫很快,而火山口邊緣由岩石材料製成,升溫較慢。

在小型小行星上已經看到了細粒物質的池塘,它們的重力足夠低,以至於撞擊會震動表面並導致更細的物質結塊。但是 Psyche 是一個大物體,所以如果它是在蕭條的底部,這對Somewhat來說既有趣又神秘。”

“這些數據表明,Psyche 的表面是異質的,在成分上存在顯著差異,”西南研究所的科學家、美國宇航局 Psyche 任務的合著者 Simone Marchi 說,他沒有參與當前的研究。 Psyche 任務的主要目標是使用伽馬射線、中子光譜儀和彩色成像儀研究小行星表面的成分。 因此,異質結構的潛在存在是 Psyche Science 團隊渴望進一步研究的東西。 “

參考:Saverio Campione、Catherine de Clare 和 Michael Shepherd 的“小行星 (16) Psyche 的異質表面”,2022 年 5 月 19 日,可在此處獲取。 地球物理研究雜誌:行星.
doi: 10.1029/2021JE007091

這項研究得到了 EAPS Crosby 傑出博士後獎學金的支持,部分得到了 Heising-Simons 基金會的支持。

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