The James Webb Space Telescope may have finally found the 1st stars in the universe

詹姆斯·韦伯太空望远镜也许终于发现了宇宙中的第一颗恒星

Astronomers have discovered that the James Webb Space Telescope (JWST) may have already found the long-sought first generation of stars born shortly after the Big Bang.

天文学家发现，詹姆斯·韦伯太空望远镜（JWST）可能已经发现了人们长期寻找的大爆炸后不久出生的第一代恒星。

These initial stars, referred to as Population III or POP III stars, dwell in a galaxy called LAP1-B which was previously studied by the $10 billion space telescope. The light from this galaxy has been travelling for 13 billion years to reach the JWST, meaning that we see LAP1-B as it was just 800 million years after the Big Bang.

这些最初的恒星，被称为第三星族或POP III恒星，居住在一个名为LAP1-B的星系中，该星系之前曾被耗资100亿美元的太空望远镜研究过。来自这个星系的光已经行进了130亿年才到达JWST，这意味着我们看到的LAP1-B是在大爆炸后的8亿年。

One of the scientists behind the discovery says this could be the first time we've seen such ancient stars. "If indeed then stars of LAP1-B are Pop III, this is the first detection of these primordial stars," team leader Eli Visbal from the University of Toledo told Space.com. "To discover POP III stars, we really needed the sensitivity of JWST, and we also needed the 100 times magnification from gravitational lensing from a galaxy cluster between us and LAP1-B."

这一发现背后的一位科学家表示，这可能是我们第一次看到如此古老的恒星。托莱多大学的团队负责人Eli Visbal告诉Space.com：“如果LAP1-B的恒星确实是Pop III，这是首次探测到这些原始恒星。”“为了发现Pop III恒星，我们真的需要JWST的灵敏度，我们还需要我们和LAP1-B之间的星系团的引力透镜放大100倍。”

This galaxy is so distant that it was only visible, even to the highly sensitive infrared vision of the JWST, thanks to a phenomenon first predicted by Albert Einstein in his 1915 theory of general relativity. Known as gravitational lensing, this phenomenon describes the magnification of light from a distant object via the warping of space by an intermediate massive body. The gravitational lens that magnified LAP1-B is a massive cluster of galaxies that lies between Earth and LAP1-B at a distance of around 4.3 billion light-years, called MACS J0416.1-2403 (MACS0416).

由于阿尔伯特·爱因斯坦在1915年的广义相对论中首次预测了一种现象，这个星系非常遥远，即使是JWST的高灵敏度红外视觉也只能看到它。这种现象被称为引力透镜，它描述了通过中间大质量物体对空间的扭曲来放大来自遥远物体的光。放大LAP1-B的引力透镜是一个巨大的星系团，位于地球和LAP1-B之间，距离约43亿光年，称为MACS J0416.1-2403（MACS0416）。

The JWST sees the galaxy LAP1-B as it was during an age of the universe called "the epoch of reionization," during which ultraviolet light from the first stars and galaxies is thought to be transforming neutral gas of hydrogen and helium into a charged superheated gas called plasma. As such, it marks the end of the "cosmic dark ages."

JWST看到了LAP1-B星系在被称为“再电离时代”的宇宙时代的样子，在此期间，来自第一批恒星和星系的紫外线被认为正在将氢和氦的中性气体转化为带电的过热气体，称为等离子体。因此，它标志着“宇宙黑暗时代”的结束。

These POP III stars are thought to have formed before this epoch; coming together around 200 million years after the Big Bang, after the universe had expanded and cooled enough to allow electrons and protons to form the first atoms of hydrogen, the lightest element in the cosmos.

这些POP III恒星被认为是在这个时代之前形成的；在宇宙大爆炸约2亿年后，在宇宙膨胀和冷却到足以让电子和质子形成宇宙中最轻的元素氢的第一个原子之后，它们聚集在一起。

"In the standard model of cosmology, POP III stars form in very small dark matter structures that serve as building blocks for larger galaxies," Visbal said. "Thus, they teach us about the earliest stages of galaxy formation and evolution. They may also constrain the properties of dark matter since alternative dark matter models impact where they first form."

Visbal说：“在宇宙学的标准模型中，POP III恒星形成于非常小的暗物质结构中，这些结构是较大星系的构建块。因此，它们告诉我们星系形成和演化的最早阶段。”。它们也可能限制暗物质的性质，因为替代的暗物质模型会影响它们最初形成的地方。

That means astronomers have been keen to identify POP III stars, but this first generation of stellar bodies has thus far proved hard to spot.

这意味着天文学家一直热衷于识别POP III恒星，但迄今为止，这第一代恒星体很难被发现。

"POP III stars have been elusive because they mostly form at early times, so they are very far away and in small clusters," Visbal said. "This makes them very faint."

“POP III恒星一直难以捉摸，因为它们大多在早期形成，所以它们离得很远，而且是小星团，”Visbal说。“这使得它们非常微弱。”

Because POP III stars were forged at a time when the universe was filled with little more than hydrogen and helium, with just a smattering of heavier elements (which astronomers call "metals"), the first generation of stars should stand out from modern "metal-rich" stars like the sun (a POP I star) due to their low-metallicity.

由于POP III恒星是在宇宙中充满氢和氦的时候锻造的，只有少量较重的元素（天文学家称之为“金属”），因此第一代恒星由于金属丰度低，应该从太阳（POP I恒星）等现代“富含金属”的恒星中脱颖而出。

This low metallicity had another impact on POP III stars, too, allowing them to reach tremendous masses equivalent to 100 times that of the sun and more. Additionally, POP III stars are also thought to cluster in relatively small groups due to their vast masses.

这种低金属丰度也对POP III恒星产生了另一个影响，使它们能够达到相当于太阳100倍甚至更多的巨大质量。此外，由于质量巨大，POP III恒星也被认为聚集在相对较小的星团中。

"Simulations indicate that since primordial gas cools less efficiently than gas with heavy elements like carbon and oxygen, there is less gas fragmentation during star formation," Visbal said. "This leads POP III stars to be more massive than metal-enriched stars, possibly with typical masses of 100 times the mass of the sun."

Visbal说：“模拟表明，由于原始气体的冷却效率低于含有碳和氧等重元素的气体，因此恒星形成过程中的气体破碎较少。这导致POP III恒星的质量比富含金属的恒星大，可能是太阳质量的100倍。”

Indeed, the team found that the stars in LAP1-B are surrounded by gas with minimal traces of metals, and that they seem to be in groups of around 1,000 solar masses.

事实上，研究小组发现，LAP1-B中的恒星被气体包围，其中金属的痕迹很小，它们似乎是1000个太阳质量的恒星群。

These findings also suggest that gravitational lensing could be an effective way to hunt for more POP III stars at early times, or at high redshifts.

这些发现还表明，引力透镜效应可能是在早期或高红移时寻找更多POP III恒星的有效方法。

"Until we did the calculation, I thought our model would find that Pop III stars are too rare at a redshift of 6.6 to be found in a strongly magnified part of a gravitational lens. I was pleasantly surprised to find that our calculation showed that they should be common enough to observe behind a cluster like MACSJ0416," Visbal concluded. "Next, we want to perform more detailed hydrodynamical simulations of the transition from Pop III to Pop II stars [the universe's second generation of stars] to see if they are consistent with the spectrum of LAP-1B and similar objects."

在我们进行计算之前，我认为我们的模型会发现，Pop III恒星的红移为6.6，太罕见了，无法在引力透镜的强放大部分找到。Visbal总结道：“我惊喜地发现，我们的计算表明，它们应该足够常见，可以在像MACSJ0416这样的星团后面观察到。接下来，我们想对从Pop III到Pop II恒星（宇宙的第二代恒星）的过渡进行更详细的流体动力学模拟，看看它们是否与LAP-1B和类似天体的光谱一致。”

The team's research was published in late October in The Astrophysical Journal Letters.

该团队的研究于10月下旬发表在《天体物理学杂志快报》上。