Astronomers have already discovered hundreds of exoplanets. But ____1____ the new kid. Which is orbiting a kind of star that models say it shouldn’t.
Researchers found the exoplanet while looking at the star HIP 13044 — or Sergio, for Star of Extra-Galactic Origin. It’s in what once was a separate galaxy, which the Milky Way ____2____ billions of years ago.
The scientists saw Sergio wobbling due to the gravitational tug of a Jupiter-sized gas planet, which the scientists dubbed Sergio Junior. They detail their find in the journal Science.
You don’t ordinarily find planets ____3____ a star like Sergio. First, it's really old — past the Red Giant phase, when stars balloon in size and ____4____ planets in close orbits. And planets tend to form around metal-rich stars, like our Sun. But Sergio has only one percent the metal content of our Sun. That doesn't ____5____ one widely accepted model of planetary formation.
The Sergios may offer a glimpse of the future of our own planetary system — in about five billion years. We hope to be back then with an update.
【视听版科学小组荣誉出品】
make way for gobbled up hanging around swallow up jibe with
发现有行星绕着不同以往类型的恒星转 天文学家已发现了数以百计的太阳系外行星。但是，现在该给新成员腾让地方了，这颗行星围绕着某颗恒星旋转，用事实证明了传统理论可不完全正确。 研究人员是在研究HIP 13044恒星的时候发现了这颗太阳系外行星。恒星HIP 13044 又名Sergio（塞尔吉奥），取“在银河系外起源的恒星”之意。它在曾经是一个独立的星系，在几十亿年前被银河系吞并了。 科学家们观察到Sergio（塞尔吉奥）由于受到一个木星大小的气态行星造成的引力而变得不稳定，科学家将这颗气态行星戏称为Sergio（塞尔吉奥）二世。他们在《科学》杂志上详细叙述了自己的发现。 通常，你不会在如Sergio（塞尔吉奥）这样的恒星周围发现行星。首先，它非常非常老了——它经历过红巨星阶段，这一阶段的恒星会急剧膨胀，吞噬在临近轨道运行的行星。而行星往往会在富含金属的恒星——好似我们的太阳这种恒星——周围形成。可Sergio（塞尔吉奥）的金属含量只有太阳的百分之一。这种情况跟一个被广泛接受的行星形成模型并不一致。 Sergios（塞尔吉奥）或许可以让我们一窥自己的行星系统——大约50亿年后的未来。到那时候，我们希望还能回来再更新 节目给大家。