관심 & 배움/과학 & 우주

외계생명체 존재 가능한 ‘슈퍼지구’ 발견

淸山에 2011. 9. 13. 14:57

 

  

  

 

 

외계생명체 존재 가능한 ‘슈퍼지구’ 발견

서울신문

 

 

유럽 천문학자들이 최근 무더기로 발견한 외계행성 50개 가운데 생명체가 존재할 가능성이 있는 이른바 슈퍼지구 행성도 포함된 것으로 밝혀져 학계가 주목하고 있다.

스위스 제네바 대학의 미셸 메이어 박사가 이끄는 연구팀은 칠레 천체망원경을 이용해 외계행성 50개를 발견했으며, 이 가운데는 지구보다 더 크지만 가스의 양이 목성보다 더 적은 슈퍼지구도 16개나 포함돼 있다고 최근 와이오밍 주에서 열린 천문학회에서 발표했다.

 

 

한꺼번에 이렇게 많은 슈퍼지구가 발견된 건 이번이 최초다. 이번 발견이 새 행성 발견에 대한 연구가 본격적으로 가속화 되는 시점이라고 보는 이들도 많다. 더욱이 발견된 16개 슈퍼지구 가운데 한 곳에는 생명체가 존재하고 있을 가능성 있는 것으로 추정돼 눈길을 끈다.

외계생명체가 살 수도 있다고 지목된 행성은 HD85512b. 태양보다 작고 온도가 낮은 주황색 항성 HD85512을 59일 주기로 도는 이 행성은 지구와는 36광년 떨어져 있다. 크기는 지구의 3.6배이며, 표면에는 생명체 존재의 필수조건인 물이 존재할 것으로 추측된다.

HD85512b는 2007년 발견된 글리제 581d에 이어 두 번째로 발견된 생명체 존재 가능성이 있는 슈퍼지구다. 이 행성 대기에 두터운 구름층이 존재해 물이 끓지 않고 기온을 낮게 유지할 수 있다면 지구처럼 액체 형태의 물이 흐르는 것도 기대할 수 있다.

하지만 아직 이 행성이 암석행성인지 목성처럼 가스가 차있는지는 알 수 없기 때문에 확신하기는 이르며 추가적인 연구와 관찰이 필요하다고 연구진은 강조했다.

강경윤기자 newsluv@seoul.co.kr

 

 
 

 

 

'Super-Earth,' 1 of 50 Newfound Alien Planets, Could Potentially Support Life

More than 50 new alien planets  including one so-called super-Earth that could potentially support life  have been discovered by an exoplanet-hunting telescope
 

 

Image: ESO/M. Kornmesser

More than 50 new alien planets — including one so-called super-Earth that could potentially support life — have been discovered by an exoplanet-hunting telescope from the European Southern Observatory (ESO).

 

The newfound haul of alien planets includes 16 super-Earths, which are potentially rocky worlds that are more massive than our planet. one in particular - called HD 85512 b - has captured astronomers' attention because it orbits at the edge of its star's habitable zone, suggesting conditions could be ripe to support life.

 

The exoplanet findings came from observations from the High Accuracy Radial velocity Planet Searcher instrument, or HARPS. The HARPS spectrograph is part of ESO's 11.8-foot (3.6-meter) telescope at the La Silla Observatory in Chile. 

[Illustration and video of alien planet HD 85512 b]

 

"The harvest of discoveries from HARPS has exceeded all expectations and includes an exceptionally rich population of super-Earths and Neptune-type planets hosted by stars very similar to our sun," HARPS team leader Michel Mayor of the University of Geneva in Switzerland said in a statement. "And even better — the new results show that the pace of discovery is accelerating." 

 

The potentially habitable super-Earth, officially called HD 85512 b, is estimated to be only 3.6 times more massive than Earth, and its parent star is located about 35 light-years away, making it relatively nearby. HD 85512 b was found to orbit at the edge of its star's habitable zone, which is a narrow region in which the distance is just right that liquid water could exist given the right conditions. [Gallery: The Strangest Alien Planets]

 

"This is the lowest-mass confirmed planet discovered by the radial velocity method that potentially lies in the habitable zone of its star, and the second low-mass planet discovered by HARPS inside the habitable zone," said exoplanet habitability expert Lisa Kaltenegger, of the Max Planck Institute for Astronomy in Germany and Harvard Smithsonian Center for Astrophysics in Boston.

 

Further analysis of HD 85512 b and the other newfound exoplanets will be able to determine more about the potential existence of water on the surface. 

 

"I think we're in for an incredibly exciting time," Kaltenegger told reporters in a briefing today (Sept. 12). "We're not just going out there to discover new continents — we're actually going out there to discover brand new worlds."

[Infographic: Alien Planet HD 85512 b Holds Possibility of Life]

 

The HARPS spectrograph is designed to detect tiny radial velocity signals induced by planets as small as Earth if they orbit close to their star.

 

Astronomers used HARPS to observe 376 sunlike stars. By studying the properties of all the alien planets detected by HARPS so far, researchers found that approximately 40 percent of stars similar to the sun is host to at least one planet that is less massive than the gas giant Saturn.

 

In other words, approximately 40 percent of sunlike stars have at least one low-mass planet orbiting around it. on the other hand, the majority of alien planets with a mass similar to Neptune appear to be in systems with multiple planets, researchers said.

Astronomers have previously discovered 564 confirmed alien planets, with roughly 1,200 additional candidate worlds under investigation based on data from the Kepler space observatory, according to NASA's Jet Propulsion Laboratory in Pasadena, Calif.

 

 

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This artist rendering provided by The Europeans Southern Observatory shows the planet orbiting the Sun-like star HD 85512 in the southern constellation of Vela (The Sail).
(AP Photo/artist rendering provided by The Europeans Southern Observatory) 
 
 

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