2026年6月25日 / 美国东部时间上午8:39 / 哥伦比亚广播公司/美联社报道
天文学家发现了一对比棉花糖还轻的巨型行星——它们是和木星一样大的超蓬松行星。
这两颗轻如鸿毛的行星围绕着1110光年外的一颗恒星运行，是目前已知密度比棉花糖还低的系外行星中体积最大的。
牛津大学的乔治·德兰斯菲尔德表示，它们是已知同尺寸行星中最轻的。
“这两颗行星的密度堪比刚从罐里挤出的一团剃须泡沫，”德兰斯菲尔德在一封邮件中说道。她和团队于周三在《皇家天文学会月报》上发表了研究成果。
德兰斯菲尔德推测，这些蓬松轻盈的星球颜色可能是白色或蓝色，具体取决于当地天空是否多云——而非棉花糖那种粉色。这两颗行星的主要成分可能是氢和氦，但需要美国国家航空航天局（NASA）的韦伯太空望远镜进行后续观测，才能证实它们的化学组成。
这两颗格外蓬松的行星由NASA的凌日系外行星勘测卫星（TESS）在过去十年间发现，它们围绕着飞鱼座（南天星座之一）的一颗恒星运行。研究人员通过地面望远镜对这两颗距离地球1110光年的行星的轨道进行了研究，从而计算出了它们的密度。一光年约等于6万亿英里。
2024年，研究人员发现了一颗距离地球1200光年的超蓬松行星，称其为“宇宙之谜”。
相比之下，木星的密度是这两颗轻质行星的35倍之多。
NASA在一份新闻稿中表示，新发现的这两颗行星的轨道周期也异乎寻常地长，分别为139天和232天。
超蓬松行星在宇宙中被认为十分罕见，它们被认为形成于新生恒星周围的气体和尘埃盘，其中气体含量多于尘埃。随着时间推移，它们会剥离掉大部分物质，甚至被进一步剥离。
“研究这些行星的主要意义在于，我们原本根本就没指望能发现它们，”位于加州硅谷的NASA艾姆斯研究中心科学处理运营中心科学主管乔恩·詹金斯说道，“它们为我们解开木星这类巨型行星和超蓬松行星的形成之谜提供了新的难题。”
NASA目前确认的太阳系外行星总数接近6300颗。据德兰斯菲尔德统计，其中超蓬松行星还不到40颗。
“最终，通过研究包含罕见行星类型的特殊系统，我们能为行星形成之谜补上更多拼图，也能进一步了解我们在宇宙中的位置，”她说道。
Astronomers find 2 gigantic planets lighter than cotton candy: “Comparable to a nice blob of shaving foam”
June 25, 2026 / 8:39 AM EDT / CBS/AP
Astronomers have uncovered a pair of giant planets that are lighter than cotton candy — super-puffs the size of Jupiter.
The featherweight pair — orbiting a star 1,110 light-years away — are the biggest exoplanets found to have less density than cotton candy.
That makes them the lightest known planets of their size, said the University of Oxford’s George Dransfield.
“These two planets have densities comparable to a nice blob of shaving foam, fresh from the can,” Dransfield said in an email. She and her team reported their findings Wednesday in Monthly Notices of the Royal Astronomical Society.
Dransfield suspects these fluffy, wispy worlds are probably white or blue, depending on whether the skies there are cloudy — not shades of cotton-candy pink. The planets are probably mostly hydrogen and helium, although it will take follow-up observations by NASA’s Webb Space Telescope to confirm their chemical makeup.
Detected by NASA’s Tess satellite over the past decade, these two especially puffy puffs orbit a star in the southern constellation Volans, known as the flying fish. The researchers studied the planets’ orbits using telescopes on Earth to determine their density, from 1,110 light-years away. A light-year is nearly 6 trillion miles.
This illustration provided by NASA depicts the Sun-like star TOI-791, background left, and two giant planets that NASA’s TESS space telescope discovered in its orbit. Daniel Rutter/NASA via AP
In 2024, researchers found a super-puff planet 1,200 light years from Earth, calling it a “cosmic mystery.”
Jupiter, by comparison, is as much as 35 times denser than these two lightweights.
The newly found planets also have unusually long orbits, with one taking 139 days and the other taking 232 days to circle the host star, NASA said in a news release.
Considered rare in the cosmos, super-puffs are thought to form around the disk of gas and dust around a newborn star where there is more gas than dust. They shed much of the material over time, stripping down even more.
“The main reason these planets are interesting to study is that we didn’t expect to see them at all,” said Jon Jenkins, the science lead for the Science Processing Operations Center at NASA’s Ames Research Center in California’s Silicon Valley. “They represent a puzzle for us to solve about how giant planets like Jupiter and the super-puffs form.”
NASA’s tally of worlds outside our solar system currently stands at nearly 6,300 confirmed. Fewer than 40 are super-puffs, according to Dransfield.
“Ultimately, by studying exotic systems containing rare planet types, we add further pieces to the puzzle of planet formation and learn more about our place in the cosmos,” she said.
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