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.
【視聽版科學小組榮譽出品】
make way for gobbled up hanging around swallow up jibe with
發(fā)現(xiàn)有行星繞著不同以往類型的恒星轉(zhuǎn) 天文學家已發(fā)現(xiàn)了數(shù)以百計的太陽系外行星。但是，現(xiàn)在該給新成員騰讓地方了，這顆行星圍繞著某顆恒星旋轉(zhuǎn)，用事實證明了傳統(tǒng)理論可不完全正確。 研究人員是在研究HIP 13044恒星的時候發(fā)現(xiàn)了這顆太陽系外行星。恒星HIP 13044 又名Sergio（塞爾吉奧），取“在銀河系外起源的恒星”之意。它在曾經(jīng)是一個獨立的星系，在幾十億年前被銀河系吞并了。 科學家們觀察到Sergio（塞爾吉奧）由于受到一個木星大小的氣態(tài)行星造成的引力而變得不穩(wěn)定，科學家將這顆氣態(tài)行星戲稱為Sergio（塞爾吉奧）二世。他們在《科學》雜志上詳細敘述了自己的發(fā)現(xiàn)。 通常，你不會在如Sergio（塞爾吉奧）這樣的恒星周圍發(fā)現(xiàn)行星。首先，它非常非常老了——它經(jīng)歷過紅巨星階段，這一階段的恒星會急劇膨脹，吞噬在臨近軌道運行的行星。而行星往往會在富含金屬的恒星——好似我們的太陽這種恒星——周圍形成?？蒘ergio（塞爾吉奧）的金屬含量只有太陽的百分之一。這種情況跟一個被廣泛接受的行星形成模型并不一致。 Sergios（塞爾吉奧）或許可以讓我們一窺自己的行星系統(tǒng)——大約50億年后的未來。到那時候，我們希望還能回來再更新 節(jié)目給大家。