ALMA Traces History of Water on Earth Back to the Interstellar Medium

ALMA追溯地球上水的歷史至星際介質

Astronomers have previously discovered water around stars, disks, comets, and planets, but until now, data on the exact ratio of water to heavy water in the disk of gas and dust orbiting a young star was lacking. From the ratio of water (H2O) to heavy water (HDO), astronomers can deduce when and where water formed.Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have detected gaseous water in the planet-forming disc around the star V883 Orionis. This water carries a chemical signature that explains the journey of water from star-forming gas clouds to planets, and supports the idea that water on Earth is even older than our Sun.

“We can now trace the origins of water in our Solar System to before the formation of the Sun,” says John J. Tobin, an astronomer at the National Radio Astronomy Observatory (NRAO), USA and lead author of the study published today (March 8) in the journal Nature.

天文學家之前已經在恒星、星盤、彗星和行星周圍發現了水，但是直到現在，還缺乏關於圍繞年輕恒星運行的氣體和塵埃盤中水與重水的確切比例數據。天文學家利用阿塔卡瑪大型毫米及次毫米波陣列（Atacama Large Millimeter/submillimeter Array，縮寫ALMA），根據水（H2O）和重水（HDO）的比例，以推斷出水形成的時間和地點。並在獵户座V883星周圍的原行星盤中探測到了氣態水。這種水帶有一些化學特徵，解釋了水從原星(恆星)形成的氣體雲到行星的旅程，證明了地球上的水甚至比太陽更古老的觀點。

這項研究2023年3月8日發表於Nature，文章第一作者John J. Tobin (National Radio Astronomy Observatory)表示：「我們現在可以追蹤太陽系中太陽形成之前水的起源。」

Tobin JJ, van 't Hoff MLR, Leemker M, van Dishoeck EF, Paneque-Carreño T, Furuya K, Harsono D, Persson MV, Cleeves LI, Sheehan PD, Cieza L. Deuterium-enriched water ties planet-forming disks to comets and protostars. Nature. 2023 Mar;615(7951) 227-230. doi:10.1038/s41586-022-05676-z. PMID: 36890372.

Link: https://www.nature.com/articles/s41586-022-05676-z