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Uma pesquisa com 10 exoplanetas do tamanho de Júpiter mostra por que alguns desses mundos parecem ter menos água do que o esperado

Uma pesquisa com 10 exoplanetas do tamanho de Júpiter realizado com telescópios Hubble e Spitzer espaciais da NASA levou uma equipe para resolver um mistério de longa data – por que alguns desses mundos parecem ter menos água do que o esperado. Os resultados oferecem novos insights sobre a ampla gama de atmosferas planetárias em nossa galáxia e como os planetas são montados.

Dos cerca de 2.000 planetas confirmados para estar orbitando outras estrelas, um subconjunto são planetas gasosos com características semelhantes
para os de Júpiter, mas orbitam muito perto das suas estrelas, tornando-as bolhas quente.
Sua proximidade com a estrela torna difícil de observar no brilho da luz das estrelas. Devido a essa dificuldade, o Hubble tem apenas explorado um punhado de Júpiteres quentes no passado. Estes estudos iniciais descobriram vários planetas para segurar menos água do que o previsto por modelos atmosféricos.

Ao combinar os dados do Hubble e Spitzer telescópios espaciais da NASA, a equipe foi capaz de alcançar um amplo espectro do comprimentos da onda de luz da cobertura do óptico ao infravermelho. A diferença de raio planetária conforme medido entre os comprimentos de onda visíveis e de infravermelhos foi usada para indicar o tipo de atmosfera planetária que se observou em cada planeta na amostra, se turva ou clara. Um planeta nublado aparecerá maior em luz visível do que em comprimentos de onda infravermelhos, que penetram mais profundamente na atmosfera. Foi essa comparação que permitiu que a equipe de encontrar uma correlação entre atmosferas nebulosas ou nublados e detecção de água leve.

 

issing Water Mystery Solved in Comprehensive Survey of Exoplanets A survey of 10 hot, Jupiter-sized exoplanets conducted with NASA’s Hubble and Spitzer space telescopes has led a team to solve a long-standing mystery -- why some of these worlds seem to have less water than expected. The findings offer new insights into the wide range of planetary atmospheres in our galaxy and how planets are assembled.   Of the nearly 2,000 planets confirmed to be orbiting other stars, a subset are gaseous planets with characteristics similar  to those of Jupiter but orbit very close to their stars, making them blistering hot. Their close proximity to the star makes them difficult to observe in the glare of starlight. Due to this difficulty, Hubble has only explored a handful of hot Jupiters in the past. These initial studies have found several planets to hold less water than predicted by atmospheric models. The international team of astronomers has tackled the problem by making the largest-ever spectroscopic catalogue of exoplanet atmospheres. All of the planets in the catalog follow orbits oriented so the planet passes in front of their parent star, as seen from Earth. During this so-called transit, some of the starlight travels through the planet’s outer atmosphere. “The atmosphere leaves its unique fingerprint on the starlight, which we can study when the light reaches us,” explains co-author Hannah Wakeford, now at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. By combining data from NASA’s Hubble and Spitzer Space Telescopes, the team was able to attain a broad spectrum of light covering wavelengths from the optical to infrared. The difference in planetary radius as measured between visible and infrared wavelengths was used to indicate the type of planetary atmosphere being observed for each planet in the sample, whether hazy or clear. A cloudy planet will appear larger in visible light than at infrared wavelengths, which penetrate deeper into the a
issing Water Mystery Solved in Comprehensive Survey of Exoplanets
A survey of 10 hot, Jupiter-sized exoplanets conducted with NASA’s Hubble and Spitzer space telescopes has led a team to solve a long-standing mystery — why some of these worlds seem to have less water than expected. The findings offer new insights into the wide range of planetary atmospheres in our galaxy and how planets are assembled.
Of the nearly 2,000 planets confirmed to be orbiting other stars, a subset are gaseous planets with characteristics similar
to those of Jupiter but orbit very close to their stars, making them blistering hot.
Their close proximity to the star makes them difficult to observe in the glare of starlight. Due to this difficulty, Hubble has only explored a handful of hot Jupiters in the past. These initial studies have found several planets to hold less water than predicted by atmospheric models.
The international team of astronomers has tackled the problem by making the largest-ever spectroscopic catalogue of exoplanet atmospheres. All of the planets in the catalog follow orbits oriented so the planet passes in front of their parent star, as seen from Earth. During this so-called transit, some of the starlight travels through the planet’s outer atmosphere. “The atmosphere leaves its unique fingerprint on the starlight, which we can study when the light reaches us,” explains co-author Hannah Wakeford, now at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
By combining data from NASA’s Hubble and Spitzer Space Telescopes, the team was able to attain a broad spectrum of light covering wavelengths from the optical to infrared. The difference in planetary radius as measured between visible and infrared wavelengths was used to indicate the type of planetary atmosphere being observed for each planet in the sample, whether hazy or clear. A cloudy planet will appear larger in visible light than at infrared wavelengths, which penetrate deeper into the a

 

Foto: NASA, ESA, and D. Sing (University of Exeter)

 

 

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