| Event ID: | 36684 |
| Contact Name: | Instituto Nacional de Pesquisas Espaciais INPE |
| Contact Email: | divulgacao.das@inpe.br |
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| Organization: | Instituto Nacional de Pesquisas Espaciais INPE |
| Event Web Site: | https://www.youtube.com/watch?v=e6DmIYKZTDE |
| Dates: | 6th October 2020 to 10th October 2020 |
| Physical Event: | No |
| Type: | Other |
| Start/End Type: | Both Starts and Ends During WSW |
| Country: | Brazil |
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| Event Name: | Seminário INPE: Planetary Habitability: Limitations and Timescales Related to Stellar Magnetic |
| Event Description: | Dia 06 de outubro às 15h Seminário: Astrofísica Planetary Habitability: Limitations and Timescales Related to Stellar Magnetic Por: Gustavo Porto de Mello, Observatório do Valongo UFRJ - http://lattes.cnpq.br/1918385364299862 O seminário será proferido em Português. Moderador: André Milone, Pesquisador da Divisão de Astrofísica INPE Resumo The habitable zone is a unifying and central concept in astrobiology, collecting different perspectives and classes of questions under a concrete model with observational and theoretical undertones. Its classical definition demands a planet of adequate mass orbiting its star at a distance which allows liquid water on the surface for long timescales. There is growing recognition that the habitable zone is a multidimensional concept and that dynamo-generated magnetic processes in low mass stars, driven by rotation and surface convective zones, significantly constrain habitability timescales. These processes convert rotational into magnetic energy, which is dissipated at the stellar surface as far ultraviolet and X-ray fluxes plus stellar winds composed of energetic particles. These high energy photons and particles affect the structure and very existence of atmospheres and water oceans of earthlike planets, having a direct bearing on the emergence and maintenance of life. This energetic early phase lasts less than 100 million years for sunlike stars yet may adversely affect the habitability of low mass planets as witnessed by the example of Mars. Very low mass stars, however, owing to low luminosities, request habitable planets to lie much closer in order to achieve adequate temperatures, exposing them to hugely enhanced X-UV fluxes and winds. Moreover, their magnetically active phase lasts many giga-years, severely taxing the ability of rocky planets to hold on to their volatile inventories. We present two case studies concerning timescales of magnetic activity and their bearing on planetary habitability. Kappa Ceti is a very sunlike star closely resembling the properties of the young Sun as life was arising on the Earth and Venus and Mars were losing their surface bodies of water. In the very low mass star domain, we approach the case of Proxima Centauri, which harbours an Earth-like planet within its habitable zone. |
| Promotional Image: | No Image. |
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| Attendance: | 0 |
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| Media Impressions: | 0 |
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