内容来源：https://www.quantamagazine.org/black-holes-or-black-hole-stars-astronomers-spar-over-webb-telescopes-little-red-dots-20260914/

内容总结：

韦布望远镜“小红点”引发天文学界激烈争论：黑洞还是“黑洞星”？

天文学家建造詹姆斯·韦布空间望远镜，本是为了捕捉宇宙大爆炸后最初十亿年间的微弱光芒。然而，即便在韦布传回的首批图像中，研究人员就发现了一批难以解读的神秘天体——它们体积微小，仅占一个像素，却发出极其耀眼的红光，亮度堪比整个星系，且几乎出现在韦布的每一张图像中。2023年，研究人员将它们命名为“小红点”。

起初，天文学家认为这些小红点类似星系；随后又判断它们更像星系中心的超大质量黑洞——黑洞本身不可见，但其强大引力剧烈吞噬周围气体，形成炽热漩涡状碎屑环，光芒盖过周围恒星。然而，2025年春季，两个研究团队同时宣布观测到两个与所有已知天体截然不同的“小红点”。德国马克斯·普朗克天文研究所的安娜·德·格拉夫表示：“在我们用地面望远镜拍摄的数百万次观测中，没有任何东西看起来像这些源。”两个团队提出，他们可能正在观测一种全新的天体：一个由氢气构成的巨大翻转结构，亮度相当于数十亿颗太阳，核心深处却隐藏着一个黑洞。他们将其命名为“黑洞星”。

在随后发表的论文中，天文学家进一步提出，韦布望远镜正在见证超大质量黑洞在巨型恒星核心中诞生的过程。夏威夷大学天文学家罗汉·奈杜称：“一种根本性的新现象正在发生。”但这一大胆解释并未获得普遍认同，反而引发了大量后续研究和关于这些奇特光点本质的激烈辩论。麻省理工学院天体物理学家安娜-克里斯蒂娜·艾勒斯表示：“这个领域已经变得非常两极分化。”

当天文学家只能看到一个光点时，所能获知的只有其颜色和亮度。最初，研究人员因小红点异常明亮而认为它们是宇宙边缘的遥远星系，但如此明亮的星系必须极为庞大，而已知机制无法在短短数亿年内使星系增长到如此规模，因此曾被戏称为“宇宙破坏者”。随后，德·格拉夫领导的“红宝石”巡天和奈杜共同领导的“海市蜃楼或奇迹”巡天利用韦布望远镜对包括小红点在内的遥远天体进行了长时间观测，通过光谱分析发现氢元素颜色被涂抹成多个色度，这通常意味着正在直视一个裸露的黑洞——黑洞以极高速度搅动周围氢气云，产生“宽线”，宽线越宽，黑洞质量越大。许多天文学家据此认为，早期宇宙中遍布大黑洞，其光芒掩盖了宿主星系中的恒星。但小红点仍然显得怪异：大多数超大质量黑洞在吞噬气体时会闪烁并发射强大X射线，而大多数小红点似乎两者皆无。

2025年春季，德·格拉夫和奈杜团队公布了两个最奇特的红点。它们异常偏红，韦布几乎未探测到蓝色光谱，且在某一特定红色波段颜色骤然增亮，呈现“巴耳末突破”特征——这通常见于炽热氢气球，如某些恒星或星系。但这两个小红点太亮，不可能是普通恒星；也不像黑洞，因为黑洞通常不产生巴耳末突破或约5000开尔文的平滑红色驼峰光谱。奈杜和德·格拉夫由此得出结论：他们看到的是黑洞星的首批样本——外观如恒星，内部却由黑洞驱动。黑洞星外部是巨大的氢气聚集物，若替换太阳，其边缘将延伸至冥王星轨道十余倍之外；外围气体不稳定沸腾，抛射物质；核心深处，黑洞吞噬气体、加热并向外推动光和能量，维持外层氢气不塌缩，犹如恒星核心的核聚变引擎。氢气外壳还会阻挡X射线并抑制闪烁，从而解释其他小红点的两大谜团。

另一研究团队则对“宽线”提出替代解释。曼彻斯特大学天文学家瓦季姆·鲁萨科夫等人发现，许多小红点的宽线山峰坡度比黑洞周围快速旋转气体所预期的更平缓，认为氢颜色展宽可能主要来自电子散射而非气体旋转。去除电子散射效应后，宽线不再那么宽，更像光穿过缓慢翻滚的氢气壳，与黑洞星预期相符。三个团队于2025年3月20日同日发布研究成果，被部分研究人员称为“黑洞星日”。奈杜表示：“我们正在看到种子。这可能是宇宙中每一个大质量黑洞的诞生。”

黑洞星理论支持者援引奥卡姆剃刀原则，认为该理论是对这两个小红点乃至一般小红点最简洁的解释。但简洁与否因人而异，天文学家已就此争论一年之久。即便首批小红点发现多年后，许多基本问题仍无定论。科尔比学院天体物理学家戴尔·科切夫斯基回忆，在2026年4月科罗拉多州阿斯彭会议上，他刚回顾完关于小红点微量蓝光的看似无争议观点，全场便爆发争论，“我们连第一个要点都没讨论完”。

许多天文学家仍认为小红点就是传统黑洞，剑桥大学的罗伯托·马约利诺便是其中之一。他对黑洞星理论的每个论点都提出反驳：缺乏闪烁？早期宇宙黑洞食物供应更稳定，进食更有序。缺乏X射线？标准星系黑洞周围有厚厚的气体尘埃环，可阻挡大部分X射线。他认为新天体的红色确实引人注目，说明黑洞与观测者之间存在大量气体，但这些气体可能是尘埃环或斑块状云团，而非黑洞星的气体壳。马约利诺与加州大学圣克鲁兹分校的皮耶罗·马道提出，小红点的红色主要取决于观测角度——最红的是侧向观测、气体环遮挡视线的黑洞；韦布也看到一些“小蓝点”，可能是同一类裸露黑洞从上方观测的结果。他们同样援引奥卡姆剃刀，认为黑洞是对各种颜色小红点的更简解释。

马萨诸塞大学阿默斯特分校天文学家毛罗·贾瓦利斯科认为，目前两种理论——黑洞或黑洞星——都能与韦布观测相符，“我不认为有令人信服的理由偏向其中任何一种”。要检验这些解释，天文学家需要更清楚地了解黑洞星如何形成及其预期外观。

过去几年，科罗拉多大学博尔德分校的米切尔·贝格尔曼一直在研究生研讨课上讲授小红点，阅读大量相关论文。在这些既不完全像恒星也不完全像黑洞的神秘天体中，他认出了一个旧识——准星。贝格尔曼曾在2006年与玛尔塔·沃隆泰里和马丁·里斯共同提出准星假说，以解释看似质量大得不可能的黑洞观测。准星理论提供了一种制造黑洞星的途径：巨大气体云核心直接塌缩形成黑洞，剩余云气环绕其周围。2025年，贝格尔曼与合作者杰森·德克斯特将准星模型应用于小红点，估计准星可在数百万年内迅速组装，随后进入更像小红点的成熟形态，并持续数千万年，足以让韦布观测到。2026年，贾瓦利斯科团队进一步完善准星模型，发现其拟合德·格拉夫和奈杜天体的光谱甚至优于初始模型。他指出，太阳也在做同样的事——隐藏其爆炸性核聚变，只是规模小得多，“我们每秒有数十亿颗氢弹爆炸，却一个都看不到”。

与此同时，研究人员开始寻找另一种区分性模式：如果小红点是早期宇宙形成的黑洞星，那么随着时间推移，它们应逐渐挣脱外壳、暴露内部黑洞，因而变得越来越稀少。2026年8月，科切夫斯基团队对红点和蓝点按不同宇宙时期进行统计，发现当宇宙年龄接近20亿至30亿年时，小红点似乎消失——这初步表明小红点作为黑洞星，可能确实是许多超大质量黑洞的一个“青春期”阶段。理论家已在推演这一阶段的具体样貌。在2026年9月8日发表的另一项分析中，奈杜、德·格拉夫、艾勒斯及合作者测试了多种推算黑洞星内部“种子”黑洞质量的方法，发现这些隐藏黑洞的质量远低于标准裸露黑洞。科学家提出，韦布正在捕捉质量可达太阳百万倍的黑洞星孕育宇宙首批大黑洞的过程。

包括科切夫斯基在内的一些研究人员仍不确定。他怀疑宇宙本身混乱复杂，有些小红点确实如黑洞星阵营所言更像恒星，另一些则更接近标准黑洞。“我有一种暗中的怀疑：我们双方可能都是对的，”他说。

中文翻译：

黑洞还是黑洞星？天文学家就韦布望远镜发现的“小红点”展开争论

引言

天文学家建造詹姆斯·韦布空间望远镜，是为了捕捉宇宙大爆炸后最初十亿年间发出的微弱光线——那是一个混沌的时代，大量氢气和氦气汇聚成我们今天所见的一条条星系链。即使在韦布拍摄的最初几张图像中，天文学家就能看到各种各样神秘的光斑。

其中一批天体尤其难以解读。它们发出刺眼的强光，辐射出长波长的红光，亮度堪比整个星系。它们体积很小，仅占一个像素。而且它们无处不在——几乎每张韦布拍摄的图像中都会出现几个。2023年，研究人员开始称它们为“小红点”。天文学家反复将韦布对准这些小红点，从这些光点像素中榨取出宝贵的新信息。

起初，研究人员认为这些红点看起来有点像星系。后来，他们得出结论，小红点更像是位于大多数星系中心的超大质量黑洞。这些庞然大物本身是暗的，但它们可怕的引力会猛烈地吞噬气体和附近的其他物质，产生一圈圈炽热旋转的碎屑环，其光芒完全盖过了周围的恒星。

然后，在2025年春天，两个天文学家团队同时宣布观测到一对与其他所有小红点都不同的红点。事实上，它们与以往见过的任何天体都不一样。

“在我们用地面望远镜进行的数百万次（观测）中，”德国海德堡马克斯·普朗克天文研究所的研究员、其中一个团队的负责人安娜·德·格拉夫说，“没有任何东西看起来像这些源。”

这两个天文学家团队提出，他们正在观察一种新的天体：一团颠倒错位的氢气，它闪耀着数十亿颗太阳的光芒，同时在其核心深处隐藏着一个黑洞。他们称之为“黑洞星”。

在上周发表的一篇论文中，天文学家将这一分析推进了一步。他们认为，韦布望远镜正在目睹超大质量黑洞在巨大恒星核心中诞生。“一种全新的现象正在发生，”夏威夷大学天文学家罗汉·奈杜说。

但并非所有人都认同这一大胆的解读。它引发了大量后续研究，并重新点燃了一场关于这些奇特光点本质的激烈争论。

“这个领域已经变得非常两极分化，”麻省理工学院研究小红点的天体物理学家安娜-克里斯蒂娜·艾勒斯说。

小红点之谜

当你只能看到一个光点时，很难判断自己看到的是什么。你所能知道的只是它的颜色和亮度。天文学家最初认为小红点是宇宙地平线上的遥远星系，主要依据是它们的亮度。但如此明亮的星系必然极其巨大——而在短短几亿年内，没有任何已知方式能让它们长到那么大。天文学家称它们为“宇宙破坏者”，因为它们似乎推翻了标准的宇宙时间线。

然后他们进行了更仔细的观察。德·格拉夫领导了一项名为“红色未知体：明亮红外河外巡天”（Rubies）的观测，奈杜共同领导了另一项名为“奇迹还是幻象”（MOM）的巡天。这是一波将韦布望远镜对准遥远天体（包括小红点）进行数小时曝光的巡天中的两项。他们精确记录了每个红点发出的光的色调，以及各色调的亮度。这种详细的颜色分解——称为光谱——向天文学家讲述了比最初观测远为详细的故事。不同的原子以微妙不同的色调发光，因此光谱能让人了解该天体粒子的运动状态。

小红点光谱中的重磅发现是，氢的颜色被抹散到了多个色调上。通常，看到这种效应意味着你正直接注视着一个裸露的黑洞。黑洞以极快的速度甩动周围的气体云，气体云根据其速度发出略微不同的颜色。最终效果是，你看到的不是氢的单一色调，而是一个颜色范围，称为“宽线”。这个范围越宽，最快的氢气云飞得越快——黑洞的质量也就越大。

许多天文学家得出结论，大黑洞遍布宇宙，掩盖了其宿主星系中恒星的光芒。作为黑洞，小红点呈现红色是因为尘埃——比气体复杂得多的颗粒物质——挡住了它们的蓝光。

然而它们看起来仍然很奇怪。大多数超大质量黑洞在吞噬周围大块气体流时会闪烁。它们还会向宇宙发射强大的X射线。大多数小红点似乎两者都没有。

但这并没有让天文学家太困扰；他们预期在早期宇宙的混乱中会看到一些奇怪的东西。至少这些黑洞没有打破任何宇宙学理论。

然后，在2025年春天，德·格拉夫和奈杜的团队公布了迄今为止最奇怪的两个红点。

一种新的解读

这两个小红点之所以与众不同，在于它们有多红。韦布在它们光谱的偏蓝色调中几乎探测不到任何光。而在某个特定的红色色调处，颜色突然变得非常非常亮。这一特征被称为“巴耳末突破”，是你在观察一团炽热的氢气时看到的现象——通常是某些类型的恒星或星系（由许多恒星组成）。在恒星核心深处，核聚变产生热量和光，慢慢渗透到恒星表面。在那里，氢原子会以一种阻挡蓝光、只让红光通过的方式被激发。这些红色具有驼峰状光谱，揭示了恒星表面的整体温度。

但新的小红点不可能真的是恒星——它们太亮了。它们也不太像黑洞。黑洞具有各种不同温度的环状结构。它们通常不会产生巴耳末突破，也不会产生指示恒星表面均匀燃烧在约5000开尔文温度的红色驼峰曲线。

奈杜和德·格拉夫得出结论，他们看到的是某种将黑洞的活力与恒星的外观结合起来的天体的首批实例：黑洞星。

从外部看，黑洞星会表现为一大团氢气聚集物。如果我们的太阳被替换为一个黑洞星，它将延伸到比冥王星轨道远十几倍的地方。向边缘方向，这颗星会不稳定地沸腾，脱落外层并爆炸性地喷射物质。“这将是一个非常混乱的系统，物质被吹出去又落回来，”德·格拉夫说。“我可不想靠得太近。”

在中心深处，外界不可见的地方，这颗星由黑洞提供能量。这个黑洞会拉扯周围的气体，急剧加热它并向外推动光和能量，从而阻止外层氢气向内坍缩。通过这种方式，黑洞将形成这颗星的“引擎”，类似于我们太阳以聚变供能的核心。向外移动，围绕黑洞旋转的物质会发出各种颜色，慢慢向表面传播。正如某些恒星一样，靠近表面的氢气会阻挡蓝光而让红光通过。德·格拉夫和奈杜的理论是，最终结果将是一个气体表面，亮度堪比一个更裸露的黑洞，但具有5000开尔文恒星的巴耳末突破和平滑红色驼峰。额外的好处是，气体“茧”还会阻挡X射线，而且气体不会闪烁太多——这解释了围绕其他小红点的两个谜团。

但那些据称由氢气围绕黑洞快速旋转产生的宽线呢？另一个研究小组提供了一个可能的解释。

该小组包括曼彻斯特大学天文学家瓦迪姆·鲁萨科夫，他们一直在仔细研究观测最充分的小红点的宽线。宽线呈尖锐山峰的形状。但鲁萨科夫及其合作者注意到，在许多情况下，这些山峰的坡度比预期来自黑洞周围快速运动气体的信号要略微平缓。因此他们提出，氢气颜色的展宽可能大部分来自光在电子上的散射，而非来自旋转的气体。

鲁萨科夫说，他们从数据中以数字方式去除了这种电子引起的模糊效应。之后，宽线看起来不再那么宽，而更像是光穿过一个特定状态下缓慢翻腾的氢气壳层，类似于你期望从黑洞星中看到的情况。三个团队——德·格拉夫的、奈杜的和鲁萨科夫的——于2025年3月20日发布了他们的发现——一些研究人员称之为“黑洞星日”。

黑洞星可能代表超大质量黑洞发展的一个新阶段：首先，一个黑洞在一层氢气的中心形成，周围伴随着一个由普通恒星组成的婴儿星系。然后，随着时间的推移，黑洞会吃掉自己的茧壳，在清除氢气的同时获得质量。

“我们看到的是种子，”奈杜说。“这可能是宇宙中每一个大质量黑洞的诞生。”

反对意见

黑洞星的支持者诉诸奥卡姆剃刀原理，认为他们的理论对这两个小红点——或许还有一般的小红点——给出了最简单的解释。但简单是主观的，天文学家在过去一年里一直在就到底发生了什么进行热烈辩论。

即使在小红点被发现数年之后，关于它们的许多问题仍无定论。科尔比学院天体物理学家戴尔·科切夫斯基回忆起在2026年4月科罗拉多州阿斯彭的一次会议上主持了一场关于小红点的讨论。他首先回顾了一个他希望不会引起争议的观点——关于它们微量的蓝光。“整个会场爆发了争论，我们甚至没能讨论完第一个要点，”他说。

许多天文学家仍然认为小红点是传统的黑洞——即使是这两个新发现的天体。“数据确实很有说服力，”剑桥大学的罗伯托·迈奥利诺说。“但我对解读持更为怀疑的态度。”

对于每一个支持黑洞星的观点，迈奥利诺都能迅速反驳。缺乏闪烁？在早期宇宙中，黑洞可能拥有更稳定的食物供应，因此可能是更整洁的进食者。缺乏X射线？标准星系黑洞周围环绕着厚厚的由气体和尘埃组成的甜甜圈状结构，可以阻挡大部分X射线。他认为没有理由怀疑小红点不是标准的超大质量黑洞。

他说，这些新天体的红色令人瞩目，他同意这意味着黑洞和我们之间必然有大量气体。但这些气体可能以甜甜圈的形式存在，也可能是填充黑洞天空斑块的蓬松云团，而不是黑洞星周围的气体壳层。迈奥利诺同意电子散射可能有助于展宽一些小赤点光谱中的谱线。但他说，电子散射也会模糊来自超大质量黑洞的氢线。

迈奥利诺和他的合作者、加州大学圣克鲁兹分校的皮耶罗·马道认为，这些红点的红色主要来自我们观测它们的角度。最红的红点是我们恰好从侧面看到的那些，它们的气体甜甜圈挡住了我们的视线。迈奥利诺和马道在2026年春天指出，韦布还看到了一些“小蓝点”。这些可能是同样的裸露黑洞，从上方俯视。他们也诉诸奥卡姆剃刀原理——在这种情况下，他们认为黑洞是对各种颜色小点更简单的解释。

在现阶段，两种理论——黑洞或黑洞星——都可能与韦布望远镜所看到的相符。“我不认为有令人信服的理由偏向其中一种，”马萨诸塞大学阿默斯特分校的天文学家毛罗·贾瓦利斯科说，他职业生涯的大部分时间都在解读遥远星系的光谱。

为了检验他们的解读，天文学家需要更清晰地了解黑洞星可能如何形成，以及它们预计会呈现怎样的面貌。

准恒星归来

过去几年里，米切尔·贝格尔曼一直在科罗拉多大学博尔德分校教授一门关于小红点的研究生研讨课。这让他不断阅读该领域如消防水管般涌出的论文。在这些既不完全像恒星也不完全像黑洞的神秘天体中，他认出了一个来自过去的幽灵：准恒星。“突然间开关啪地一响，我意识到这就是准恒星应该看起来的样子，”贝格尔曼说。

贝格尔曼曾在2006年与玛尔塔·沃隆泰里和马丁·里斯一起提出准恒星的存在，以解释看似不可能存在的超大质量黑洞的观测结果。

他们的准恒星理论提供了一种制造黑洞星的方式：一大片气体云的核心坍缩直接形成一个黑洞，将云的剩余部分聚集在周围。

2025年，贝格尔曼和他的合作者杰森·德克斯特将准恒星模型应用于小红点。他们估计准恒星可以在几百万年内迅速组装成型，然后稳定为一种看起来就像小红点的更成熟形态。它们会以这种状态持续数千万年——足够长的时间让韦布发现它们。

2026年，贾瓦利斯科与一个团队合作，充实了准恒星模型作为黑洞星起源的框架，他发现这是解释小红点如何能掩盖进食黑洞迹象的一种自然方式。他指出，我们的太阳也在玩同样的把戏，隐藏其爆炸性的聚变，只是规模小得多。“我们每秒钟有数十亿颗氢弹在爆炸，然而我们一个都看不到，”他说。

贾瓦利斯科及其合作者发现，他们新的准恒星模型比最初的模型更好地拟合了德·格拉夫和奈杜天体的光谱。他认为准恒星理论是对小红点的一个合理解释，但仍对其他想法持开放态度。“我只想知道真相，”他说。

与此同时，研究人员开始寻找另一种区分性模式：如果小红点是早期宇宙中形成的黑洞星，那么随着时间的推移，它们应该变得越来越稀有，因为它们各自挣脱外壳并露出内部的黑洞。

在2026年8月对按不同时代分类的红色和蓝色小点进行的一项统计中，科尔比学院的科切夫斯基及其合作者恰好发现了这种模式。在数据中，当宇宙接近20亿到30亿年年龄时，小红点似乎消失了——这是初步证据表明，小红点作为黑洞星，可能确实是许多超大质量黑洞类似青春期的阶段。

理论家们已经在研究这个类似青春期的阶段可能是什么样的。在9月8日发表的另一项分析中，奈杜、德·格拉夫、艾勒斯及其合作者测试了多种技术来推算黑洞星内部黑洞“种子”的质量。这些隐藏的黑洞似乎比标准的裸露黑洞质量小得多。科学家们提出，韦布正在捕捉超大质量黑洞星——质量可达太阳的100万倍——正在孵育宇宙首批大黑洞的过程。

包括科切夫斯基在内的一些研究人员仍不确定。科切夫斯基怀疑宇宙是一个混乱的地方，一些小红点确实像黑洞星阵营所论证的那样具有恒星特征。他认为，其他的则更可能像另一个阵营所论证的标准黑洞。“我有一种暗中的怀疑，我们两边都是对的，”他说。

英文来源：

Black Holes or Black Hole Stars? Astronomers Spar Over Webb Telescope’s ‘Little Red Dots.’
Introduction
Astronomers built the James Webb Space Telescope to pick up faint light from the first billion years after the Big Bang, a chaotic era when vast swaths of hydrogen and helium gas gathered into the chains of galaxies we see today. Even in the telescope’s first images, astronomers could see a whole zoo of mysterious smears of light.
One batch of objects proved especially difficult to interpret. They glowed blindingly bright, emitting red light with long wavelengths and shining as brilliantly as a whole galaxy. They were tiny, spanning just a pixel. And they were everywhere. A couple appear in almost every image Webb takes. In 2023, researchers started calling them “little red dots.” Astronomers have repeatedly pointed Webb toward the little red dots, wringing precious new information from these pixels of light.
Initially, researchers thought the dots looked kind of like galaxies. Later, they concluded that little red dots look more like the supermassive black holes that sit at the heart of most galaxies. These monstrous masses are themselves dark, but their formidable gravity violently vacuums up gas and other nearby matter, generating rings of hot, swirling detritus that completely outshine the stars around them.
Then, in the spring of 2025, two teams of astronomers simultaneously announced observations of a pair of little red dots that were unlike all the rest. In fact, they were unlike any object ever seen.
“In all the millions of [observations] we’ve taken with ground-based telescopes,” said Anna de Graaff, a researcher at the Max Planck Institute for Astronomy in Heidelberg, Germany, and head of one group, “there’s nothing that looks like these sources.”
The two teams of astronomers propose that they are looking at a new astronomical object: a topsy-turvy lump of hydrogen that shines with the light of billions of suns while hiding a black hole deep in its core. They call it a black hole star.
In a paper posted last week, astronomers took this analysis a step further. They argued that the Webb telescope is witnessing the births of supermassive black holes inside the cores of colossal stars. “There is a fundamentally new phenomenon afoot,” said Rohan Naidu, an astronomer at the University of Hawai‘i.
But not everyone agrees with this bold interpretation. It has sparked a flurry of follow-up research and reignited a fierce debate over the nature of these peculiar pinpricks of light.
“The field has gotten very polarized,” said Anna-Christina Eilers, an astrophysicist at the Massachusetts Institute of Technology who studies little red dots.
The Mystery of the Little Red Dots
When all you can see is a speck, it’s hard to tell what you’re looking at. All you know about it is its color and brightness. Astronomers first argued that little red dots were distant galaxies on the cosmic horizon, mainly because of their brightness. But galaxies that bright would have to be huge — and there was no known way for them to grow so big in just hundreds of millions of years. Astronomers dubbed them “universe breakers” for the way they seemed to demolish the standard cosmic timeline.
Then they took a closer look. De Graaff led one survey, called Red Unknowns: Bright Infrared Extragalactic Survey (Rubies), and Naidu co-led another survey, called Mirage or Miracle (MOM). These were two of a wave of surveys that trained Webb telescope on distant objects, including little red dots, for hours at a time. They tabulated precisely what shades of light were coming from each dot, and how bright the shades were. This detailed color breakdown, known as a spectrum, told astronomers a far more detailed story than the initial observations had. Different atoms shine in subtly different hues, so the spectrum provided a sense of what the object’s particles were doing.
The bombshell discovery in the little red dot spectra was that the colors of hydrogen were smeared out across multiple shades. Usually, seeing such an effect means you’re looking straight at an exposed black hole. Black holes whip hydrogen clouds around them at furious rates, with the clouds emitting slightly different colors depending on their speed. The net effect is that instead of seeing just the hue of hydrogen, you see a range of colors called a broad line. The wider this range, the faster the fastest hydrogen clouds are flying — and the more massive the black hole.
Many astronomers concluded that big black holes dotted the universe, washing out the light of the stars in their host galaxies. As black holes, the little red dots would appear red because dust — grainy stuff much more complicated than gas — was blocking their blue light.
Yet they still seemed weird. Most supermassive black holes flicker as they gulp down chunky streams of gas around them. They also beam powerful X-rays across the universe. Most little red dots seemed to be doing neither of these things.
But that didn’t trouble astronomers much; they expected to see some strangeness during the pandemonium of the early universe. And at least the black holes weren’t breaking any cosmological theories.
Then, in the spring of 2025, de Graaff and Naidu’s teams unveiled the two strangest dots yet.
A New Interpretation
What made these two little red dots exceptional was how red they were. Webb picked up almost no light in the bluer hues of their spectra. And at a particular shade of red, the colors abruptly got much, much brighter. This feature, known as a Balmer break, is something you see when looking at a hot ball of hydrogen gas — typically, certain types of stars or galaxies (which are made of many stars). Deep in a star’s core, nuclear fusion pumps out heat and light, which slowly filters up to the star’s surface. There, hydrogen atoms can become energized in a way that blocks bluer light and lets through only redder light. These red colors have a hump-shaped spectrum that reveals the overall temperature of the star’s surface.
But the new little red dots couldn’t literally be stars — they were way too bright. And they didn’t look much like black holes either. Black holes have an assortment of ringlike structures of different temperatures. They don’t typically produce a Balmer break, or the red, hump-shaped curve indicative of a stellar surface burning at a uniform 5,000 or so degrees Kelvin.
Naidu and de Graaff concluded that they were looking at the first examples of something combining the vigor of a black hole with the outward appearance of a star: a black hole star.
From the outside, a black hole star would appear as a huge agglomeration of hydrogen gas. If our sun were replaced with a black hole star, it would extend a dozen times farther than the orbit of Pluto. Out toward the edge, the star would boil unstably, sloughing off outer layers and explosively ejecting mass. “It’s going to be a very messy system where stuff is being blown out and falling back in,” de Graaff said. “I wouldn’t want to come too close.”
Deep in the center, invisible to the outside world, the star would be powered by a black hole. This black hole would pull gas around it, dramatically heating it and pushing light and energy outward, which would keep the outer layers of hydrogen from collapsing inward. In this way, the black hole would form the “engine” of the star, analogous to the fusion-powered core of our sun. Moving outward, material swirling around the black hole would beam out a range of colors that would slowly make their way toward the surface. And as with certain stars, the hydrogen near the surface would stop the bluer light while letting the redder light pass through. The end result would be a gassy surface shining as brightly as a more exposed black hole but with the Balmer break and smooth red hump of a 5,000-kelvin star, de Graaff and Naidu theorized. As a bonus, the gas “cocoon” would also block X-rays, and the gas wouldn’t flicker much — which would explain two mysteries surrounding other little red dots.
But what about the broad lines, supposedly caused by hydrogen swirling fast around a black hole? Another group provided a possible explanation.
The group, which included Vadim Rusakov, an astronomer at the University of Manchester, had been scrutinizing the broad lines of the best-observed little red dots. Broad lines take the shape of a sharp mountain peak. But Rusakov and collaborators noticed that in many cases, these mountains sloped slightly more gently than would be expected if they came from fast-moving gas around a black hole. So they suggested that instead of coming from rotating gas, much of the spread of the hydrogen colors could come from light scattering off electrons.
They digitally removed the effect of this electron-induced smudging from their data, Rusakov said. After that, the broad lines stopped looking quite so broad and started looking more like light passing through a sluggishly churning shell of hydrogen gas in a particular state, similar to what you’d expect to see from a black hole star. The three teams — de Graaff’s, Naidu’s, and Rusakov’s — posted their findings on March 20, 2025 — “black hole star date,” as some of the researchers called it.
Black hole stars could represent a new stage in the development of a supermassive black hole: First, a black hole would form in the center of a shell of hydrogen, together with a baby galaxy of normal stars around it. Then, over time, the black hole would eat its way out of its cocoon, gaining mass as it cleared the hydrogen gas away.
“We are seeing the seed,” Naidu said. “This is the birth of potentially every massive black hole in the universe.”
The Argument Against
The black hole star enthusiasts appeal to Occam’s razor, arguing that their theory gives the simplest accounting of these two little red dots, and perhaps of little red dots in general. But simple is subjective, and astronomers have spent the last year in a lively debate about what’s really going on.
Even years after the discovery of the first little red dot, not much about them is settled. Dale Kocevski, an astrophysicist at Colby College, recalls leading a discussion about them at an April 2026 conference in Aspen, Colorado. He started by recapping what he hoped would be an uncontroversial idea about their trace amounts of blue light. “The group erupted into argument, and we couldn’t even get past the first bullet point,” he said.
Many astronomers still argue that little red dots are traditional black holes — even the new duo. “The data is really compelling,” said Roberto Maiolino of the University of Cambridge. “I’m a little bit more dubious about the interpretation.”
For each point in favor of black hole stars, Maiolino fires off a quick rebuttal. The lack of flicker? In the early universe, black holes may have had a steadier food supply and may therefore have been tidier eaters. The lack of X-rays? Standard galactic black holes are ringed by a thick doughnut of gas and dust, which can block most X-rays. He sees no reason to suspect the little red dots of being anything other than standard supermassive black holes.
The redness of the new objects is striking, he said, and he agrees that it means there must be a ton of gas between the black hole and us. But that gas could come in the form of the doughnut, or as puffy clouds that fill in patches of the black hole’s sky, as opposed to the shell of gas around a black hole star. Maiolino agrees that electron scattering likely contributes to broadening the lines in the spectra of some of the little red dots. But electron scattering also smears hydrogen lines from supermassive black holes, he said.
Maiolino and his collaborator, Piero Madau of the University of California, Santa Cruz, argue that the redness of the dots comes mainly from the angle at which we see them. The reddest dots are those that we happen to see edge on, their gassy doughnuts blocking our view. Webb also sees some “little blue dots.” These could be the same exposed black holes, viewed top-down, Maiolino and Madau pointed out in spring 2026. They also appeal to Occam’s razor — in this case arguing that black holes are a simpler explanation for little dots of all colors.
At this stage either theory — black hole or black hole star — could match what Webb telescope has seen. “I don’t think that there is a compelling reason to prefer one or the other,” said Mauro Giavalisco, an astronomer at the University of Massachusetts, Amherst who has spent much of his career interpreting the spectra of distant galaxies.
To test their interpretations, astronomers need a clearer picture of how black hole stars might form and how exactly they expect them to look.
Return of the Quasi-Star
Over the last few years, Mitchell Begelman has been teaching a graduate student seminar on little red dots at the University of Colorado, Boulder. It’s kept him reading the firehose of papers coming out on the subject. In these mysterious objects that weren’t quite stars and weren’t quite black holes, he recognized a ghost from his past: the quasi-star. “Suddenly the switch flipped, and I realized that this is what quasi-stars should look like,” Begelman said.
Begelman had proposed the existence of quasi-stars back in 2006, along with Marta Volonteri and Martin Rees, to explain observations of what looked like impossibly massive black holes.
Their quasi-star theory offers one way to make a black hole star: The core of a vast gas cloud collapses to directly form a black hole, gathering the remainder of the cloud around it.
In 2025, Begelman and his collaborator Jason Dexter applied the quasi-star model to the little red dots. They estimated that quasi-stars could quickly assemble themselves in a few million years before settling into a more mature form that would look just like little red dots. They would do this for tens of millions of years — lasting long enough for Webb to spot them.
In 2026, Giavalisco worked with a team to flesh out the quasi-star model as an origin for black hole stars, which he finds to be a natural way of explaining how little red dots could mask the signs of a feeding black hole. He points out that our sun performs the same trick, hiding its explosive fusion, just on a much smaller scale. “We have billions and billions of hydrogen bombs exploding every second, and yet we see none of them,” he said.
Giavalisco and his collaborators found that their new model of a quasi-star fit the spectra of de Graaf’s and Naidu’s objects even better than the initial models had. He thinks the quasi-star theory is a plausible explanation for the little red dots but remains open to other ideas. “I just want to know the truth,” he said.
In the meantime, researchers are starting to search for another distinguishing pattern: If little red dots are black hole stars formed in the early universe, then they should grow rarer over time as they each break free from their shells and reveal their inner black holes.
In an August 2026 census of both red and blue dots broken up into different eras, Kocevski of Colby College and his collaborators found exactly that pattern. In the data, as the universe approaches 2 billion to 3 billion years of age, the little red dots seem to vanish — preliminary evidence that little red dots, as black hole stars, might really be a puberty-like phase for many supermassive black holes.
Theorists are already working out what that puberty-like phase might be like. In another analysis, posted on September 8, Naidu, de Graaff, Eilers, and their collaborators tested out an assortment of techniques for deducing the mass of a black hole “seed” inside a black hole star. These hidden black holes seemed to be far less massive than standard, exposed black holes. The scientists propose that Webb is catching supermassive black hole stars — up to 1 million times the mass of the sun — in the act of incubating the universe’s first big black holes.
Some researchers, including Kocevski, still aren’t sure. Kocevski suspects that the universe is a messy place, and that some little red dots are truly as starlike as the black hole star camp is arguing. Others, he thinks, will be more like standard black holes, as the other camp argues. “I have a sneaking suspicion that we’re both right,” he said.