A recent study has revealed that all the seven exoplanets 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 exoplanets outside of solar system.
सितारे in the galaxies have stellar systems comprising mainly of their ग्रहों and satellites. For example, our home stellar system viz. solar system has nine ग्रहों (of varying densities, sizes and compositions) and their satellites. Mercury, Venus, Earth and मार्च, चार ग्रहों 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 ग्रह Earth in the stellar system of Sun is unique in supporting life.
The quest for habitable worlds beyond Earth means search for habitable ग्रहों in the stellar systems of other सितारों. There could be trillions of planets outside of the solar system. Such ग्रहों कहा जाता है exoplanets. Does any of the innumerable exoplanets support life? Any such exoplanet can only be terrestrial one with hard rocky surface like Earth. Study of terrestrial exoplanets 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.
बौना सितारा TRAPPIST-1 was discovered in 1999. This ultra-cool star is situated at a distance of 40 light years. In 2016, three exoplanets were reported in the stellar system of this सितारा which was revised to seven subsequently in 2017. Three of the exoplanets are thought to be in habitable zone (1) .
The knowledge about these exoplanets 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 ग्रहों have rocky surfaces hence Earth-like terrestrial planets. And, these are closely located in कक्षाओं in close proximity to the star. The latest finding reported is that all the planets are of similar densities and made of similar materials.
Using space 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 exoplanets have similar densities and Earth-like composition possibly due to little less iron content than the Earth (2,3).
घनत्व और संरचना की समझ में यह नवीनतम विकास ग्रहों in the stellar system of TRAPPIST-1 is significant because it builds the knowledge-base for a model of understanding of Earth-like exoplanets outside of solar system.
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सूत्रों का कहना है:
- नासा 2017. समाचार - नासा दूरबीन ने एकल तारे के चारों ओर पृथ्वी के आकार, रहने योग्य क्षेत्र के ग्रहों के सबसे बड़े बैच का खुलासा किया। 21 फरवरी 2017 को पोस्ट किया गया। पर ऑनलाइन उपलब्ध है https://exoplanets.nasa.gov/news/1419/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around-single-star/ 25 जनवरी 2021 को एक्सेस किया गया।
- नासा 2021। जेपीएल न्यूज - एक्सोप्लानेट्स - 7 रॉकी ट्रैपिस्ट -1 ग्रह इसी तरह की सामग्री से बने हो सकते हैं। 22 जनवरी 2021 को पोस्ट किया गया। https://www.jpl.nasa.gov/news/the-7-rocky-trappist-1-planets-may-be-made-of-similar-stuff/
- एगोल ई।, डोर्न सी।, एट अल 2021। ट्रैपिस्ट -1 के ट्रांजिट-टाइमिंग और फोटोमेट्रिक विश्लेषण को परिष्कृत करना: मास, रेडी, घनत्व, गतिशीलता, और एफेमेराइड्स। द प्लैनेटरी साइंस जर्नल, वॉल्यूम 2, नंबर 1। 2021 जनवरी 22 को प्रकाशित। डीओआई: https://doi.org/10.3847/PSJ/abd022
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