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تسجيل مستخدم جديدهل يمكن أن يكاد الهجرة الجوپيرية تسريع تطور الغلاف الجوي لفينوس؟
Could the Migration of Jupiter have Accelerated the Atmospheric Evolution of Venus?
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في دراسة سبل سكنان الكواكب وتطور الغلاف الجوي الأرضي، يظل الانحدار في ظروف السطح بين الفينوس والأرض مجالاً من البحوث النشطة. بين التأثيرات الذاتية والخارجية على تاريخ المناخ الفينوسي هي التغيرات المؤثرة في المدار الناجمة عن نقل الكواكب العملاقة التي تحمل كل من الإشعاع الواقع والتسخين المثلج. هنا، نقدم نتائج دراسة تطرق لتأثير موقع اليوبيتر على المعلمات المدارية للفينوس والسيناريوهات المحتملة لخسارة الماء الناجمة عن ذلك. تظهر تحليلات الديناميكا الخاصة بنا أن العديد من سيناريوهات نقل اليوبيتر المحتملة قد أدت إلى نسب مؤولات مدارية للفينوس تصل إلى 0.31. نقيم آثار الإشعاع المؤول المرتفع، بما في ذلك الإشعاع الحراري السطحي والإشعاع الضوئي المتغير المتوقع من الشمس الضعيفة الشابة. وتظهر الحسابات لوقت التجديد المثلج ان نسبة التسخين المثلج المرتفعة مطلوبة لتقليل نسبة الإشعاع المؤول للفينوس إلى القيمة الحالية، مما يدل على وجود مخزون ماء عالي الأولي. كما نقدر آثار نسبة الإشعاع المؤول المرتفعة على فقدان الماء، ونحتسب أن نسبة فقدان الماء قد زادت على الأقل بنسبة 5٪ نسبة إلى السيناريو المدار الدائري. ونحاول التأكيد على أن هذه التغيرات في الإشعاع المؤول للفينوس الشاب قد تسرعت تطور الغلاف الجوي للفينوس بشكل لا مردود إلى حالة الحمام الغابون المشتعل. وقد يزيد وجود الكواكب العملاقة في أنظمة الكواكب الخارجية من المناحي المتوقعة للفينوس المشابهة في تلك الأنظمة.
In the study of planetary habitability and terrestrial atmospheric evolution, the divergence of surface conditions for Venus and Earth remains an area of active research. Among the intrinsic and external influences on the Venusian climate history are orbital changes due to giant planet migration that have both variable incident flux and tidal heating consequences. Here, we present the results of a study that explores the effect of Jupiters location on the orbital parameters of Venus and subsequent potential water loss scenarios. Our dynamical simulations show that various scenarios of Jovian migration could have resulted in orbital eccentricities for Venus as high as 0.31. We quantify the implications of the increased eccentricity, including tidal energy, surface energy flux, and the variable insolation flux expected from the faint young Sun. The tidal circularization timescale calculations demonstrate that a relatively high tidal dissipation factor is required to reduce the eccentricity of Venus to the present value, which implies a high initial water inventory. We further estimate the consequences of high orbital eccentricity on water loss, and estimate that the water loss rate may have increased by at least $sim$5% compared with the circular orbit case as a result of orbital forcing. We argue that these eccentricity variations for the young Venus may have accelerated the atmospheric evolution of Venus towards the inevitable collapse of the atmosphere into a runaway greenhouse state. The presence of giant planets in exoplanetary systems may likewise increase the expected rate of Venus analogs in those systems.
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