A recent study has revealed that all the seven 외계 행성 in the stellar system of TRAPPIST-1 have similar densities and Earth-like composition.This is significant because it builds the knowledge-base for a model of understanding of Earth-like 외계 행성 outside of solar system.
별 in the galaxies have stellar systems comprising mainly of their 행성 and satellites. For example, our home stellar system viz. solar system has nine 행성 (of varying densities, sizes and compositions) and their satellites. Mercury, Venus, Earth and 화성, 네 행성 closet to Sun have rocky surfaces hence are referred to as terrestrial planets. On the other hand, Jupiter, Saturn, Uranus, Neptune are made of gases. The 행성 Earth in the stellar system of Sun is unique in supporting life.
The quest for habitable worlds beyond Earth means search for habitable 행성 in the stellar systems of other 별. There could be trillions of planets outside of the solar system. Such 행성 부르다 외계 행성. Does any of the innumerable 외계 행성 support life? Any such exoplanet can only be terrestrial one with hard rocky surface like Earth. Study of terrestrial 외계 행성 therefore, is a very interesting area of study. The exoplanet community is an active research community in pursuit of identifying potential life-bearing worlds in the stars outside of the solar system.
난쟁이 별 TRAPPIST-1 was discovered in 1999. This ultra-cool star is situated at a distance of 40 light years. In 2016, three 외계 행성 were reported in the stellar system of this 별 which was revised to seven subsequently in 2017. Three of the exoplanets are thought to be in habitable zone (1) .
The knowledge about these 외계 행성 in the stellar system of TRAPPIST-1 is growing continuously. The earlier studies had revealed that these planets are roughly the size and mass of the Earth. This meant these 행성 have rocky surfaces hence Earth-like terrestrial planets. And, these are closely located in 궤도 in close proximity to the star. The latest finding reported is that all the planets are of similar densities and made of similar materials.
사용 공간 and ground-based telescopes, the scientists have done a precise measurement of the transit times (the time taken by the planets to transit the star measured indirectly by dips in the brightness of the star when the planets cross in front of it) which enabled them refine the mass ratios of the planets to the star. Following this, they carried out photodynamical analysis and derived the densities of the star and the planets. This revealed that all the seven 외계 행성 have similar densities and Earth-like composition possibly due to little less iron content than the Earth (2,3).
밀도 및 구성에 대한 이해의 최신 개발 행성 in the stellar system of TRAPPIST-1 is significant because it builds the knowledge-base for a model of understanding of Earth-like 외계 행성 outside of solar system.
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출처 :
- NASA 2017. 뉴스 – NASA 망원경은 단일 항성 주위에 지구 크기의 거주 가능 영역 행성의 가장 큰 배치를 보여줍니다. 21년 2017월 XNUMX일 게시. https://exoplanets.nasa.gov/news/1419/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around-single-star/ 25년 2021월 XNUMX일에 액세스함.
- NASA 2021. JPL 뉴스 – EXOPLANETS - 7개의 암석 TRAPPIST-1 행성이 비슷한 물질로 만들어졌을 수 있습니다. 22년 2021월 XNUMX일에 게시됨. https://www.jpl.nasa.gov/news/the-7-rocky-trappist-1-planets-may-be-made-of-similar-stuff/
- Agol E., Dorn C., et al 2021. TRAPPIST-1: 질량, 반경, 밀도, 역학 및 천문력의 이동 타이밍 및 광도 분석 개선. The Planetary Science Journal, 2권, 1호. 2021년 22월 XNUMX일 발행. DOI: https://doi.org/10.3847/PSJ/abd022
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