The calcium in our bones and teeth likely came from stars exploding in supernovas and scattering this mineral across the universe in massive quantities, according to a new study.
根據一項新研究，咱們骨骼及牙齒中的鈣可能來自，以超新星方式爆炸，而大量將此礦物散佈宇宙的恆星。
We truly are made of star stuff, as famed astronomer Carl Sagan once said.
In fact, half of the calcium in the universe likely came from calcium-rich supernovae. But these explosions have turned out to be incredibly rare events that scientists have had difficulty observing and analyzing, so they weren't sure how the calcium was created.
如同著名天文學家，Carl Sagan曾經陳述過的，這確實由來自恆星的物質組成。事實上，宇宙中半數鈣可能來自富含鈣的超新星。不過，此些爆炸已經證實是，科學家們一直難以觀測與分析之非常罕見的事件。因此，他們並不確定鈣如何產生。
Explosions and mergers of stars are also known to create other heavy elements, like gold and platinum. But the calcium has presented more of a mystery.
That changed when a global team of almost 70 scientists from around the world collaborated after receiving a tip from an amateur astronomer. The study published Wednesday in The Astrophysical Journal.
恆星的爆炸與合併已知產生，諸如黃金及白金等，其他重元素。不過，鈣的存在卻是一個謎。在收到一名業餘天文學家的提示之後，一支來自世界各地，將近70名科學家的世界性團隊共同研究時，上述情況改變了。該項研究發表於，2020年8月5日(星期三)的美國天文學會所屬《天體物理學期刊》。
In April 2019, Joel Shepherd observed a bright burst as he observed the spiral galaxy called Messier 100, which is 55 million light-years away, through his telescope. He also spied a dot that was bright orange. Shepherd shared his observation with the astronomy community through a survey.
在2019年4月，當Joel Shepherd透過其望遠鏡，觀察5千5百萬光年外，被稱為梅西耶100的旋渦星系時，觀察到一處明亮的爆炸。他也發現了，一個橙色的明亮點。透過一項勘測報告，Shepherd與天文學界分享了他的觀察。
The news spread like wildfire among the community and telescopes from across the world were aimed at the galaxy and its anomaly. The event was named SN2019ehk.
消息如野火般，在天文學界中散布。因此，來世界各地的望遠鏡，以該星系及其異常點為目標。此事件被命名為SN2019ehk。
NASA's orbiting Neil Gehrels Swift Observatory, the Lick Observatory in California and the W.M. Keck Observatory in Hawaii, which researchers at Northwestern University can access remotely, all were turned toward the anomaly.
於美國西北大學的研究人員們能向，美國航太總署所屬，繞軌運行的尼爾·蓋勒斯·斯威夫特觀測衛星、位於加州的利克天文台及位於夏威夷的W.M.凱克天文台進行遠端存取，且全轉向了上述異常點。
They requested that Keck observe the event in optical light, while University of California Santa Barbara graduate student Daichi Hiramatsu used the Swift observatory to observe it in X-ray and ultraviolet light.
他們要求W.M.凱克天文台使用可見光觀測此事件，而加州大學聖塔芭芭拉分校研究生，Daichi Hiramatsu使用了斯威夫特觀測衛星，以X-射線及紫外線光進行觀察。
These follow-up observations of the event occurred about 10 hours after the supernova was detected, and X-ray emissions from the explosion were only visible for about five days before they disappeared from view.
此些對該事件的追蹤觀測發生於，該超新星被發現後大約10小時，而來自此爆炸放射出的X-射線，在從視線消失前，僅可見達約5天。
"Observing supernovae within hours of explosion is the new 'it' thing in our field right now," said Wynn Jacobson-Galan, study author, first-year Northwestern graduate student and National Science Foundation Graduate Research Fellow, via email. "As this particular supernova revealed, when you discover something so young, you now have access to the final moments of the star's life right before explosion."
該項研究撰文人，美國西北大學一年級暨獲得美國國家科學基金會獎學金的研究生，Wynn Jacobson-Galan經由電子郵件宣稱：「爆炸後數小時內觀測超新星，目前在他們的研究領域中，是新的'極致'成就。因為這顆特殊超新星透露了，當發現某事物很清新時，目前人們擁有了得悉，就在爆炸前，此恆星壽命最後剎那的途徑。」
In fact, scientists had observed a calcium-rich supernova. The X-rays revealed intriguing new information about the explosion and the star itself before it exploded.
實際上，科學家們曾經觀測到一顆富含鈣的超新星。X-射線透露了，有關此爆炸及該恆星爆炸前，其本身引入感興趣的新資訊。
"The stars responsible for calcium-rich supernovae shed layers of material in the last months before explosion," Jacobson-Galan said. "The X-rays are the result of the explosion violently colliding with this ejected material and stimulating a brilliant burst of high energy photons."The heat and pressure of the explosion actually drives the chemical reaction that creates calcium, the researchers said.
Jacobson-Galan宣稱：「導致富含鈣之超新星的恆星，在爆炸前最後幾個月，散發出若干物質層。X-射線是爆炸與該噴出物質猛烈撞擊，及激發高能光子明亮爆炸的結果。」此些研究人員表示，實際上，爆炸的熱量及壓力驅動了，產生鈣的化學反應。
Usually, only a small amount of calcium is produced by each star as it burns through its supply of helium. However, when a calcium-rich supernova occurs, massive amounts of calcium are created and released in a matter of seconds.
通常，每顆恆星透過其氦氣的供應燃燒時，僅產生少量鈣。不過，當富含鈣的超新星發生時，於大約數秒內，產生並釋出巨量鈣。
"The explosion is trying to cool down," said Raffaella Margutti, senior study author and assistant professor of physics and astronomy in Northwestern's Weinberg College of Arts and Sciences. "It wants to give away its energy, and calcium emission is an efficient way to do that."
該項研究資深撰文人，美國西北大學溫伯格文理學院的物理暨天文學助理教授，Raffaella Margutti宣稱：「爆炸降溫時，必須拋棄其能量，而釋出鈣是達成降溫的一種有效方式。」
This occurs because the hot ball of material created by the explosion is trying to reach an equilibrium with its environment, Jacobson-Galan said.
Jacobson-Galan表示，上述情況發生是因為，由此爆炸產生的熱物質球，試圖與其環境達成平衡。
"Calcium-rich supernovae produce just enough additional calcium in the explosion to provide an efficient means of emitting photons that in turn release heat," he said. "Nature chooses the path of least resistance and calcium provides that path when enough of it is present in a supernova."
他宣稱：「在爆炸中，富含鈣的超新星，僅產生足夠的額外鈣來提供一種，依序釋出熱量之發出光子的有效方式。大自然選擇阻力最小的途徑，而在超新星中存在足夠的鈣時，提供了那途徑。」
And SN 2019ehk emitted the most calcium ever observed a single event, the researchers said.
此些研究人員表示，SN 2019ehk事件釋出了，單一事件曾經被觀測到的最多鈣。
"It wasn't just calcium rich," Margutti said. "It was the richest of the rich."
The Hubble Space Telescope has observed this galaxy for the last 25 years, but never actually registered the particular star that caused this calcium-rich explosion. That's likely because it was very faint, either a white dwarf, or a dead exploded core of a star, or a very low-mass star, Jacobson-Galan said.
Margutti宣稱：「它不只是鈣豐富。它是豐富之最。」Jacobson-Galan表示，過去哈伯太空望遠鏡，已經觀測此星系達25年。不過，未曾實際記錄過，導致此富含鈣之爆炸的特殊恆星。那很可能是因為，此恆星非常昏暗，不是一顆白矮星，就是一顆核心爆炸過之停止活動的恆星，或是一顆非常低質量的恆星。
"Without this explosion, you wouldn't know that anything was ever there," Margutti added. "Not even Hubble could see it." That faint nature is also possibly true of calcium-rich supernovae as well, when compared to common supernovae that occur when massive stars die.
Margutti附言：「沒有此爆炸，人們不會知曉任何曾在那裡的東西。甚至哈伯太空望遠鏡也無法看到它。」同樣地，當與巨大恆星死亡時發生的常見超新星相較時，富含鈣的超新星也可能具有那種昏暗本質。
"This makes finding new calcium-rich supernovae difficult to see large distances from the Earth," Jacobson-Galan said. "Future telescope surveys that can scan the sky every night and see further into space will detect many more of these supernovae."
Jacobson-Galan宣稱：「這使得難以確認，在離地球很遠的地方，發現新富含鈣的超新星。未來能每晚掃描蒼穹且進一步深入太空的望遠鏡，將會發現更多的此些超新星。」
This includes the upcoming Vera Rubin Observatory. The scientitsts' finding suggested that the stars responsible for these explosions must be undergoing some sort of instability, which then causes the ejection of the star's outer layers right before explosion, he said.
這包括於智利建構中，即將到來的維拉魯賓天文台。他表示，此些科學家們的發現暗示，導致此些爆炸的恆星諒必經歷了某種，之後就在爆炸前，導致恆星諸多外層噴出的不穩定狀態。
The researchers are working on a follow-up study that includes how the supernova is evolving after the explosion. They are also refocusing their search to include X-ray emissions from calcium-rich supernovae, which was entirely unexpected until this observation.
此些研究人員正致力於，一項包括爆炸後該超新星如何演變的追蹤研究。他們也正重新將其搜尋集中於，包括在此觀測之前，來自富含鈣超新星，完全出乎意料之放射出的X-射線。
"We are designing observing strategies that would allow us to find a supernova when they are very young (and faint) and immediately repoint the X-ray spacecraft to catch the bright but short lived X-ray emission," Margutti said.
Margutti宣稱：「我們正在進行策劃，能使我們得以找尋很年幼(且昏暗)之超新星，並立即重新將X-射線航天器(望遠鏡)朝向此超新星，以捕捉明亮卻短壽命之X射線放射的策略。」
原文網址：https://edition.cnn.com/2020/08/05/health/calcium-supernova-discovery-trnd-scn/index.html
翻譯：許東榮
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