外星星球正在走向“毁灭的边缘”

外星星球正在走向“毁灭的边缘”

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

专家们一直在密切关注一颗离其恒星非常近的系外行星，它很可能处于“毁灭的边缘”。

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.

这颗行星被称为NGTS-10b，是一颗“热木星”，它是一颗气体巨星，围绕其恒星运行。到目前为止，大约有400颗系外行星符合“热木星”的定义，但这颗特殊的行星一年只持续18个小时，使得它正“危险地接近”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.”

该研究的主要作者詹姆斯·麦考马克在一份声明中说:“尽管从理论上讲，短轨道周期(少于24小时)的热木星是最容易被探测到的，因为它们体积大，凌日频繁，但事实证明它们极其罕见。”“目前已知的数百颗热木星中，只有7颗的轨道周期不到24小时。”

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

NGTS-10b的18小时轨道是迄今为止发现的轨道最短的“热木星”。

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大约有100亿年的历史，不属于宜居区——尽管这个星球的表面可能存在液态水。它距离地球1000光年。一光年相当于6万亿英里。

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.

这颗行星很可能被潮汐锁定(它的一侧总是面向恒星)，所以天文学家估计它的平均温度超过1000摄氏度或华氏1832度。NGTS-10b大概比木星本身大20%，质量是木星的两倍多。大家还认为，NGTS-10比同样有大约100亿年的历史太阳低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.

该研究的合著者戴维·布朗(David Brown)和另一位合著者丹尼尔·贝利斯(Daniel Bayliss)表示，这种大小、轨道特别短的行星最终会分裂。

“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说:“在未来的10年里，我们可能会看到这颗行星螺旋上升。”“未来十年内，我们将能够使用NGTS来监测这一情况。如果我们能看到轨道周期开始减少，行星开始螺旋上升，这将告诉我们很多我们还不知道的关于行星结构的信息。”

“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补充说:“要么是我们看到它生命的最后阶段，要么是它在这里生存的时间比预期的要长。”

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

这项研究发表在《皇家天文学会月刊》上。