quinta-feira, 23 de julho de 2015

Nasa encontra planeta similar à Terra em potencial zona habitável

Planeta Kepler-452b é 60% maior que a Terra e orbita a estrela Kepler 452.
Informação foi divulgada nesta quinta-feira pela agência espacial americana.

Do G1, em São Paulo









Cientistas da Nasa divulgaram nesta quinta-feira (23) que descobriram um exoplaneta com características muito similares à Terra e que orbita uma estrela semelhante ao Sol.
O planeta Kepler-452b foi chamado pelos cientistas de "primo distante" da Terra. Ele é 60% maior e tem boa chance de ser rochoso, embora sua massa e composição ainda não tenham sido determinados.
Ele demora 385 dias para dar uma volta completa ao redor de sua estrela, chamada de Kepler-452, astro do sistema que está a 1.400 anos-luz de distância da Terra.
Concepção artística mostra o exoplaneta Kepler-452b, o primeiro com tamanho aproximado da Terra a ser encontrado em uma zona habitável (Foto: NASA/JPL-Caltech/T. Pyle)Concepção artística mostra o exoplaneta Kepler-452b, o primeiro com tamanho aproximado da Terra a ser encontrado em uma zona habitável (Foto: NASA/JPL-Caltech/T. Pyle)


Essa estrela é um pouco mais velha que o Sol (tem "só" 1,5 bilhão de anos a mais), tem a mesma temperatura, é 20% mais brilhante e possui um diâmetro 10% maior.
Os achados desta quinta foram publicados no periódico "The Astronomical Journal". Com a descoberta, aumentou para 521 o total de exoplanetas descobertos pelo satélite Kepler.
'Condições necessárias para a vida'
Em comunicado divulgado pela Nasa, Jon Jenkins, chefe do projeto do satélite Kepler, disse que a descoberta fornece uma oportunidade de entender e refletir sobre o ambiente em evolução da Terra.
[...] Devem existir todos os ingredientes e as condições necessárias para a vida existir
neste planeta"
Jon Jenkins, chefe do projeto do satélite Kepler
"É inspirador considerar que esse planeta já vive há 6 bilhões de anos na área habitável dessa estrela, mais do que a Terra. Isso é uma oportunidade substancial para a vida surgir, devem existir todos os ingredientes e as condições necessárias para a vida existir neste planeta", afirmou o pesquisador.
Além desse achado, foram descritos ainda outros 11 candidatos à planeta que também estão em zona habitável.
A busca de planetas similares à Terra é uma das maiores aventuras na pesquisa espacial, e embora já tenham sido detectadas centenas de planetas do tamanho do nosso e outros menores, eles circulam em órbitas próximas demais de suas estrelas para que haja água líquida em sua superfície.
Comparação feita pela Nasa mostra o Sol e a Terra (à esquerda) e a estrela Kepler-452 com o planeta Kepler-452b (Foto: NASA/JPL-Caltech/T. Pyle)Comparação feita pela Nasa mostra o Sol e a Terra (à esquerda) e a estrela Kepler-452 com o planeta Kepler-452b (Foto: NASA/JPL-Caltech/T. Pyle)

Comparação entre o Sistema Kepler-452 e o Sistema Solar feita pela agência espacial americana, a Nasa (Foto: NASA/JPL-CalTech/R. Hurt)Comparação entre o Sistema Kepler-452 e o Sistema Solar feita pela agência espacial americana, a Nasa (Foto: NASA/JPL-CalTech/R. Hurt)
 www,g1,globo.com

NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth



Kepler-452b and Earth
This artist's concept compares Earth (left) to the new planet, called Kepler-452b, which is about 60 percent larger in diameter.
Credits: NASA/JPL-Caltech/T. Pyle

Scale of Kepler-452b System
This size and scale of the Kepler-452 system compared alongside the Kepler-186 system and the solar system. Kepler-186 is a miniature solar system that would fit entirely inside the orbit of Mercury.
Credits: NASA/JPL-CalTech/R. Hurt

Kepler Planet Candidates July 2015
There are 4,696 planet candidates now known with the release of the seventh Kepler planet candidate catalog - an increase of 521 since the release of the previous catalog in January 2015.
Credits: NASA/W. Stenzel

Twelve Small Habitable Zone Kepler Planets
Since Kepler launched in 2009, twelve planets less than twice the size of Earth have been discovered in the habitable zones of their stars.
Credits: NASA/N. Batalha and W. Stenzel

Kepler-452 in space
This artist's concept depicts one possible appearance of the planet Kepler-452b, the first near-Earth-size world to be found in the habitable zone of star that is similar to our sun.
Credits: NASA/JPL-Caltech/T. Pyle
NASA's Kepler mission has confirmed the first near-Earth-size planet in the “habitable zone” around a sun-like star. This discovery and the introduction of 11 other new small habitable zone candidate planets mark another milestone in the journey to finding another “Earth.” 
The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone -- the area around a star where liquid water could pool on the surface of an orbiting planet -- of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030.
"On the 20th anniversary year of the discovery that proved other suns host planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble the Earth and our Sun," said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “This exciting result brings us one step closer to finding an Earth 2.0."
Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. While its mass and composition are not yet determined, previous research suggests that planets the size of Kepler-452b have a good chance of being rocky.
While Kepler-452b is larger than Earth, its 385-day orbit is only 5 percent longer. The planet is 5 percent farther from its parent star Kepler-452 than Earth is from the Sun. Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger.
“We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment," said Jon Jenkins, Kepler data analysis lead at NASA's Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b. "It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth. That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.”
To help confirm the finding and better determine the properties of the Kepler-452 system, the team conducted ground-based observations at the University of Texas at Austin's McDonald Observatory, the Fred Lawrence Whipple Observatory on Mt. Hopkins, Arizona, and the W. M. Keck Observatory atop Mauna Kea in Hawaii. These measurements were key for the researchers to confirm the planetary nature of Kepler-452b, to refine the size and brightness of its host star and to better pin down the size of the planet and its orbit.
The Kepler-452 system is located 1,400 light-years away in the constellation Cygnus. The research paper reporting this finding has been accepted for publication in The Astronomical Journal.
In addition to confirming Kepler-452b, the Kepler team has increased the number of new exoplanet candidates by 521 from their analysis of observations conducted from May 2009 to May 2013, raising the number of planet candidates detected by the Kepler mission to 4,696. Candidates require follow-up observations and analysis to verify they are actual planets.
Twelve of the new planet candidates have diameters between one to two times that of Earth, and orbit in their star's habitable zone. Of these, nine orbit stars that are similar to our sun in size and temperature.
“We've been able to fully automate our process of identifying planet candidates, which means we can finally assess every transit signal in the entire Kepler dataset quickly and uniformly,” said Jeff Coughlin, Kepler scientist at the SETI Institute in Mountain View, California, who led the analysis of a new candidate catalog. “This gives astronomers a statistically sound population of planet candidates to accurately determine the number of small, possibly rocky planets like Earth in our Milky Way galaxy.”
These findings, presented in the seventh Kepler Candidate Catalog, will be submitted for publication in the Astrophysical Journal. These findings are derived from data publicly available on the NASA Exoplanet Archive.
Scientists now are producing the last catalog based on the original Kepler mission’s four-year data set. The final analysis will be conducted using sophisticated software that is increasingly sensitive to the tiny telltale signatures of Earth-size planets.
Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.
For more information about the Kepler mission, visit:
A related feature story about other potentially habitable planets is online at:http://www.nasa.gov/jpl/finding-another-earth
-end-
Felicia Chou
Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov
Michele Johnson
Ames Research Center, Moffett Field, Calif.
650-604-6982
michele.johnson@nasa.gov
Last Updated: July 23, 2015
Editor: Michele Johnson

www.nasa.gov

NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth




NASA's Kepler mission has confirmed the first near-Earth-size planet in the “habitable zone” around a sun-like star. The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone -- the area around a star where liquid water could pool on the surface of an orbiting planet -- of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030. For more information about the Kepler mission, please visit http://www.nasa.gov/kepler For more information about NASA Ames, please visit http://www.nasa.gov/ames.

www,nasa.gov

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