離我們最近的恒星也有一顆地球大小的行星環(huán)繞著它

離我們最近的恒星也有一顆地球大小的行星環(huán)繞著它

Researchers have confirmed that our sun's nearest celestial neighbor — Proxima Centauri — has a planet in tow. And from here, it looks a lot like Earth.

研究人員已經證實，我們的太陽最近的天體鄰居——比鄰星擁有一顆行星。從這方面看，它很像地球。

The planet, according to research published this week in the journal Astronomy & Astrophysics, boasts a mass of 1.17 Earth masses and orbits its stars in a brisk 11.2 days. It's also in the so-called "Goldilocks zone" — meaning it holds to an orbit that’s neither too hot nor too cold for the possibility of liquid water.

根據本周發(fā)表在《天文學與天體物理學》雜志上的一項研究，這顆行星的質量為地球的1.17倍，圍繞恒星公轉的時間為11.2天。它也位于所謂的“適居帶”——這意味著它的軌道既不太熱也不太冷，不可能存在液態(tài)水。

And liquid water, of course, is something of a holy grail in the search for life beyond our planet. Not only that, but at 4.2 light- years away, it's relatively close. That proximity is why the existence of the planet, Proxima b, was already suspected back in 2013, according to The Independent.

當然，液態(tài)水是尋找外星生命的圣杯。不僅如此，在4.2光年之外，它也相當接近。據《獨立報》報道，這就是為什么早在2013年，人們就懷疑比鄰星的存在。

This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to our solar system. (Photo: ESO/M. Kornmesser)

Its confirmation came courtesy of ESPRESSO, a new-generation spectrograph that’s mounted on the aptly named Very Large Telescope in Chile. Short for Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, ESPRESSO is considered the most precise planet-hunting sensor in operation. It's the successor to HARPS, a similar, but much more limited instrument.

它的確認來自于新一代的光譜儀ESPRESSO，它被安裝在智利的一個非常大的望遠鏡上，這個望遠鏡的名字很貼切。ESPRESSO是用于巖石系外行星和穩(wěn)定光譜觀測的梯形光譜儀的簡稱，被認為是運行中最精確的行星探測傳感器。它是豎琴的后繼者，豎琴是一種類似的樂器，但功能有限得多。

"We were already very happy with the performance of HARPS, which has been responsible for discovering hundreds of exoplanets over the last 17 years," Francesco Pepe, the University of Geneva astrophysicist who heads the ESPRESSO program, explains in a press release.

負責ESPRESSO項目的日內瓦大學天體物理學家弗朗西斯科·佩佩在一份新聞稿中解釋說:“我們對HARPS的表現已經非常滿意，它在過去17年里發(fā)現了數百顆系外行星。”

"We're really pleased that ESPRESSO can produce even better measurements, and it's gratifying and just reward for the teamwork lasting nearly 10 years."

“我們真的很高興ESPRESSO可以產生更好的測量結果，這是令人滿意的，也是對持續(xù)近10年的團隊合作的回報。”

ESPRESSO can measure the radial velocity of stars like Proxima Centauri with an accuracy of 11.8 inches per second — sensitive enough to determine if a star has any rocky planets in its entourage.

ESPRESSO可以測量像比鄰星這樣的恒星的徑向速度，精度為11.8英寸/秒，足夠靈敏，可以確定恒星周圍是否有巖石行星。

And sure enough, when trained on Proxima Centauri, ESPRESSO sniffed out a promising planet. Although it's a lot closer to its host star than Earth is our own sun, it basks in about the same amount of energy. That means its surface temperature could be comparable, which in turn, raises the possibility that water flows there.

果然，當在比鄰星上訓練時，ESPRESSO發(fā)現了一顆大有希望的行星。雖然它比地球離太陽更近，但它吸收的能量和太陽差不多。這意味著它的表面溫度可以比較，這反過來提高了水在那里流動的可能性。

But there's a catch. Proxima Centauri isn't like the sun we know. As a red dwarf, it's constantly radiating X-rays — several hundred times more than what we receive here on Earth.

但有個問題。比鄰星不像我們所知的太陽。作為一顆紅矮星，它不斷地發(fā)出x射線——比我們在地球上接收到的還要多幾百倍。

If there's life on Proxima b, it has found a way to overcome that steady bombardment. Or, as the researchers, suggest, the planet itself may have developed its own X-ray shielding atmosphere.

如果比鄰星上有生命，它已經找到了一種克服持續(xù)轟擊的方法?；蛘撸缪芯咳藛T所說，行星本身可能已經形成了自己的x射線屏蔽大氣層。

"Is there an atmosphere that protects the planet from these deadly rays?" study co-author Christophe Lovis muses in the release. "And if this atmosphere exists, does it contain the chemical elements that promote the development of life (oxygen, for example)? How long have these favourable conditions existed?"

研究報告的合著者克里斯托弗·洛維斯在新聞稿中沉思道:“是否有大氣層保護地球免受這些致命射線的傷害?如果這種大氣存在，它是否含有促進生命發(fā)展的化學元素(例如氧氣)?這些有利條件存在多久了?”

While Earth-like planets are being discovered with increasing frequency — thanks to new, more powerful telescopes and sensory equipment — the confirmation of Proxima b is a particularly exciting development.

由于新的、更強大的望遠鏡和感官設備的出現，類地行星被發(fā)現的頻率越來越高，而Proxima b的確認是一個特別令人興奮的進展。

Mostly because it's so close — just 4.2-million light-year rocket ride away. And also because it points to even more exciting discoveries in the future, thanks to ESPRESSO's planet-hunting prowess.

主要是因為它離我們很近，只有420萬光年的火箭飛行距離。同時也因為它指出了未來更令人興奮的發(fā)現，這要歸功于ESPRESSO的行星搜尋能力。

"ESPRESSO has made it possible to measure the mass of the planet with a precision of over one-tenth of the mass of Earth," Nobel-Prize-winning physicist Michel Mayor notes in the release. "It's completely unheard of."

諾貝爾獎得主、物理學家米歇爾·馬約爾在新聞稿中寫道:“ESPRESSO使測量地球質量的精度超過地球質量的十分之一成為可能。這完全是聞所未聞。”