A recent study has revealed that all the seven exoplanetas 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 exoplanetas outside of solar system.
Estrellas in the galaxies have stellar systems comprising mainly of their planetas and satellites. For example, our home stellar system viz. solar system has nine planetas (of varying densities, sizes and compositions) and their satellites. Mercury, Venus, Earth and Marte, El cuatro planetas 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 avión Earth in the stellar system of Sun is unique in supporting life.
The quest for habitable worlds beyond Earth means search for habitable planetas in the stellar systems of other estrellas. There could be trillions of planets outside of the solar system. Such planetas son llamados exoplanetas. Does any of the innumerable exoplanetas support life? Any such exoplaneta can only be terrestrial one with hard rocky surface like Earth. Study of terrestrial exoplanetas therefore, is a very interesting area of study. The exoplaneta community is an active research community in pursuit of identifying potential life-bearing worlds in the stars outside of the solar system.
El enano estrella TRAPPIST-1 was discovered in 1999. This ultra-cool star is situated at a distance of 40 light years. In 2016, three exoplanetas were reported in the stellar system of this estrella which was revised to seven subsequently in 2017. Three of the exoplanets are thought to be in habitable zone (1) .
The knowledge about these exoplanetas 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 planetas have rocky surfaces hence Earth-like terrestrial planets. And, these are closely located in órbitas in close proximity to the star. The latest finding reported is that all the planets are of similar densities and made of similar materials.
Usar espacio 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 exoplanetas have similar densities and Earth-like composition possibly due to little less iron content than the Earth (2,3).
Este último desarrollo en la comprensión de la densidad y composición de planetas in the stellar system of TRAPPIST-1 is significant because it builds the knowledge-base for a model of understanding of Earth-like exoplanetas outside of solar system.
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Fuentes:
- NASA 2017. Noticias - El telescopio de la NASA revela el lote más grande de planetas de zonas habitables del tamaño de la Tierra alrededor de una sola estrella. Publicado el 21 de febrero de 2017. Disponible online en https://exoplanets.nasa.gov/news/1419/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around-single-star/ Consultado el 25 de enero de 2021.
- NASA 2021. JPL News - EXOPLANETS -Los 7 planetas Rocky TRAPPIST-1 pueden estar hechos de cosas similares. Publicado el 22 de enero de 2021. 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. Refinando el tiempo de tránsito y el análisis fotométrico de TRAPPIST-1: masas, radios, densidades, dinámica y efemérides. The Planetary Science Journal, Volumen 2, Número 1. Publicado el 2021 de enero de 22. DOI: https://doi.org/10.3847/PSJ/abd022
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