外星星球正在走向“毀滅的邊緣”

外星星球正在走向“毀滅的邊緣”

Experts have been intensely watching an exoplanet that is so close to its star, it may well be on the “edge of destruction.”

專家們一直在密切關(guān)注一顆離其恒星非常近的系外行星，它很可能處于“毀滅的邊緣”。

Known as NGTS-10b, this planet is a “hot Jupiter,” a gas giant that orbits its star very closely. So far, approximately 400 exoplanets have met the “hot Jupiter” definition, but this particular one has a year that only lasts 18 hours, making it “perilously close” to its star.

這顆行星被稱為NGTS-10b，是一顆“熱木星”，它是一顆氣體巨星，圍繞其恒星運(yùn)行。到目前為止，大約有400顆系外行星符合“熱木星”的定義，但這顆特殊的行星一年只持續(xù)18個小時，使得它正“危險地接近”它的恒星。

“Although in theory hot Jupiters with short orbital periods (less than 24 hours) are the easiest to detect due to their large size and frequent transits, they have proven to be extremely rare,” the study’s lead author, James McCormac, said in a statement. “Of the hundreds of hot Jupiters currently known there are only seven that have an orbital period of less than one day.”

該研究的主要作者詹姆斯·麥考馬克在一份聲明中說:“盡管從理論上講，短軌道周期(少于24小時)的熱木星是最容易被探測到的，因?yàn)樗鼈凅w積大，凌日頻繁，但事實(shí)證明它們極其罕見。”“目前已知的數(shù)百顆熱木星中，只有7顆的軌道周期不到24小時。”

The 18-hour orbit of NGTS-10b is the shortest discovered for a “hot Jupiter” to date.

NGTS-10b的18小時軌道是迄今為止發(fā)現(xiàn)的軌道最短的“熱木星”。

NGTS-10b, which is believed to be roughly 10 billion years old, is not in the habitable zone — an area that could allow for liquid water to be on the surface.— and is 1,000 light-years from Earth. One light-year is the equivalent of 6 trillion miles.

NGTS-10b大約有100億年的歷史，不屬于宜居區(qū)——盡管這個星球的表面可能存在液態(tài)水。它距離地球1000光年。一光年相當(dāng)于6萬億英里。

The planet is likely tidally locked (one side of it always faces the star), meaning astronomers estimate its average temperature to be more than 1,000 degrees Celsius or 1,832 degrees Fahrenheit. NGTS-10b is believed to be 20 percent larger than Jupiter itself and more than twice its mass. It’s also believed that the star, NGTS-10, is 1,000 degrees cooler than the sun and is roughly 10 billion years old as well.

這顆行星很可能被潮汐鎖定(它的一側(cè)總是面向恒星)，所以天文學(xué)家估計(jì)它的平均溫度超過1000攝氏度或華氏1832度。NGTS-10b大概比木星本身大20%，質(zhì)量是木星的兩倍多。大家還認(rèn)為，NGTS-10比同樣有大約100億年的歷史太陽低1000度。

Planets of this size with exceptionally short orbits are believed to eventually tear themselves apart, the study’s co-author, David Brown said, with another co-author, Daniel Bayliss, adding it could happen in the next decade.

該研究的合著者戴維·布朗(David Brown)和另一位合著者丹尼爾·貝利斯(Daniel Bayliss)表示，這種大小、軌道特別短的行星最終會分裂。

“Over the next 10 years, it might be possible to see this planet spiraling in,” Bayliss said. “We’ll be able to use NGTS to monitor this over a decade. If we could see the orbital period start to decrease and the planet start to spiral in, that would tell us a lot about the structure of the planet that we don’t know yet.”

Bayliss說:“在未來的10年里，我們可能會看到這顆行星螺旋上升。”“未來十年內(nèi)，我們將能夠使用NGTS來監(jiān)測這一情況。如果我們能看到軌道周期開始減少，行星開始螺旋上升，這將告訴我們很多我們還不知道的關(guān)于行星結(jié)構(gòu)的信息。”

“Either we are seeing it in the last stages of its life, or somehow it’s able to live here longer than it should,” Bayliss added.

Bayliss補(bǔ)充說:“要么是我們看到它生命的最后階段，要么是它在這里生存的時間比預(yù)期的要長。”

The research was published in the scientific journal Monthly Notices of the Royal Astronomical Society.

這項(xiàng)研究發(fā)表在《皇家天文學(xué)會月刊》上。