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Astrophysical Seminar (23 January 2020, 11:00)

Опубликовано: 17/01/2020

1) Speaker: Shingo Kameda (College of Science Rikkyo University, Japan)

Title:  “Extended Exospheres of Earth-like Exoplanets”

Abstract: Many Earth-sized planets have already been discovered and some seem located in the habitable zone. Moreover, several Earth-sized planets were recently detected around low temperature stars near the Solar system. However, it is difficult to characterize them as Earth-like or Venus-like, even though they are relatively close to us. Transit spectroscopy for exoplanetary atmosphere has been performed to characterize larger exoplanets but it requires very high accuracy for much smaller Earth-like planets.
Earth’s exosphere is far-extended, but Venus’ and Mars’ hydrogen exosphere is not so much because of its low temperature of upper atmosphere. This is caused by the difference of mixing ratio of CO2 in the upper atmosphere. On Earth, CO2 was removed from its atmosphere by a carbon cycle with its ocean and tectonics. Translating these arguments to exoplanets in a habitable zone presents a possible marker to distinguish an Earth-like planet from a Mars-like or Venus-like planet. The expanded exospheres can be observed in UV, during the exoplanet transit event in a primary eclipse.

2) Speaker: A.P. Topchieva (INASAN)

Title:  “Morphology and evolution of infrared ring nebulae around HII regions”

Abstract: see Russian version

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