Gas and dust swirl in the Taurus Molecular Cloud (TMC-1) as seen by the Herschel 空间 Observatory. (来源: ESA/Herschel/NASA/JPL-Caltech; acknowledgement: R. 伤害,姓名; Cc比sa 3.0 IGO)
An international team of researchers has uncovered what might be a critical step in the chemical evolution of molecules in cosmic “stellar nurseries.“在太空中这些巨大的冷气体和尘埃云中, 数以万亿计的分子在数百万年里旋转在一起. The collapse of these interstellar clouds eventually gives rise to young stars and planets.
比如人体, 恒星托儿所包含大量有机分子, 它们主要由碳和氢原子组成. 该小组的研究结果， 2月出版. 6在杂志上 自然天文学, reveal how certain large organic molecules may form inside these clouds. It’s one tiny step in the eons-long chemical journey that carbon atoms undergo—forming in the hearts of dying stars, 然后成为行星的一部分, 地球上甚至更远的地方的生物.
“在这些寒冷的分子云中, 你正在创造第一个积木, 最后, 形成恒星和行星,乔迪·鲍曼说, 研究助理 大气与空间物理实验室 (LASP)和美国大学的助理教授 化学系 在博彩平台推荐.
按此放大
图形显示如何六边形 昊图公司-benzyne molecules can combine with methyl radicals to form a series of larger organic molecules, 每个都包含一个由五个碳原子组成的环. (资料来源:亨利·卡德威尔)
对于这项新研究, Bouwman and his colleagues took a deep dive into one stellar nursery 特别是: the Taurus Molecular Cloud (TMC-1). This region sits in the constellation Taurus and is roughly 440 light years (more than 2 quadrillion miles) from Earth. The chemically complex environment is an example of what astronomers call an “accreting starless core.“它的云已经开始崩塌, 但科学家们还没有探测到它内部出现的胚胎恒星.
The team's findings hinge on a deceptively simple molecule called 昊图公司-benzyne. 利用地球上的实验和计算机模拟, the researchers showed that this molecule can readily combine with others in space to form a wide range of larger organic molecules.
换句话说，小的积木会变成大的积木.
和, Bouwman说, those reactions could be a sign that stellar nurseries are a lot more interesting than scientists give them credit for.
“We’re only at the start of truly understanding how we go from these small building blocks to larger molecules,他说. “I think we’ll find that this chemistry is so much more complex than we thought, 即使是在恒星形成的最初阶段.”
的观察
鲍曼是一位宇宙化学家, studying a field that blends chemistry and astronomy to understand the churning chemical reactions that happen deep in space.
On the surface, he said, cold molecular clouds might not seem like a hotbed of chemical activity. 顾名思义, 这些星系的原始汤往往是寒冷的, often hovering around -263 degrees Celsius (about -440 degrees Fahrenheit), 只比绝对零度高10度. 大多数反应至少需要一点点热量才能启动.
But cold or not, complex chemistry seems to be happening in stellar nurseries. TMC-1, 特别是, contains surprising concentrations of relatively large organic molecules with names like fulvenallene and 1- and 2-ethynylcyclopentadiene. Chemists call them “five-membered ring compounds” because they each contain a ring of carbon atoms shaped like a pentagon.
“Researchers kept detecting these molecules in TMC-1, but their origin was unclear,鲍曼说.
现在，他和他的同事们认为他们找到了答案.
2021年，研究人员使用 40米射电望远镜 in Spain found an unexpected molecule hiding in the clouds of gas of TMC-1: 昊图公司-benzyne. 鲍曼解释说，这个小分子, 由六个碳原子和四个氢原子组成的环, 是化学世界里外向的人之一吗. It easily interacts with a number of other molecules and doesn’t require a lot of heat to do so.
“反应没有障碍，”鲍曼说. “That means it has the potential to drive complex chemistry in cold environments.”
全景图 瑞士光源 他在瑞士保罗·谢勒研究所工作. Researchers used ultraviolet light generated at this synchotron facility to study the products of chemical reactions that may occur inside stellar nurseries. (来源: CC的照片 通过 维基共享)
找出罪魁祸首
为了找出TMC-1中发生了什么样的复杂化学反应, 鲍曼和他的同事来自美国, 德国, the Netherlands and Switzerland—turned to a technique called “photoelectron photoion coincidence spectroscopy.” The team used light generated by a giant facility called a synchotron light source to identify the products of chemical reactions. 他们看到了邻苯和甲基自由基, 分子云的另一个常见组成部分, 容易结合形成更大更复杂的有机化合物.
The team then drew on computer models to explore the role of 昊图公司-benzyne in a stellar nursery spread out over several light-years deep in space. The results were promising: The models generated clouds of gas containing roughly the same mix of organic molecules that astronomers had observed in TMC-1 using telescopes.
Ortho-benzyne, 换句话说, seems to be a prime candidate for driving the gas-phase organic chemistry that occurs within these stellar nurseries, Bouwman说.
He added that scientists still have a lot of work to do to fully understand all of the reactions happening in TMC-1. 他想要检验, 例如, how organic molecules in space also pick up nitrogen atoms—key components of the DNA and amino acids of living organisms on Earth.
“Our findings may just change the view on what ingredients we have in the first place to form new stars and new planets,鲍曼说.
Co-authors on the new paper include researchers at Leiden University in the Netherlands, 美国本尼迪克特学院.S., the University of Würzburg in 德国 and Paul Scherrer Institute in Switzerland.
