8 new planets found in ‘Goldilocks zone’, NASA may find Earth’s ‘twin’ very soon


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NASA is closer than ever to finding a twin for the Earth, astronomers said today, announcing the discovery of eight new planets that circle in the habitable zones of their stars.

Two of the eight are the most Earth-like of any known planets found so far outside our solar system, astronomers told the 225th meeting of the American Astronomical Society in Seattle, Washington.

The pair are likely to have hard, rocky surfaces in addition to being an orbiting distance from their stars that is neither too hot nor too cold for water and possibly life to exist, astronomers said. The discovery doubles the number of known planets that are close in size to the Earth and believed to be in the so-called “Goldilocks zone” of the stars they orbit.

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Representational image. AFP

“We are now closer than we have ever been to finding a twin for the Earth around another star,” said Fergal Mullally of the Kepler Science Office. “These candidates represent the closest analogs to the Earth’s own system found to date.”

The worlds were found with the help of NASA’s planet-hunting Kepler mission, a space telescope which has scoured more than 150,000 stars for planets beyond our solar system since its launch in 2009. The latest trove of candidate planets found by Kepler and announced today was 554, bringing the total potential planets to 4,175.

Scientists have recently verified the existence of the 1,000th planet found by Kepler.

“Three of the newly validated planets are located in their distant suns’ habitable zone, the range of distances from the host star where liquid water might exist on the surface of an orbiting planet,” NASA said in a statement. “Of the three, two are likely made of rock, like Earth.”

While it is intriguing to consider the possibility of life existing on another planet like ours, the two best candidates are so far away that learning more about them presents a big challenge.

Source : firstpost

ALMA Identifies Gas Spirals as a Nursery of Twin Stars


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With new Atacama Large Millimeter/submillimeter Array (ALMA) observations, astronomers led by Shigehisa Takakuwa, Associate Research Fellow at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taiwan, have found spiral arms of molecular gas and dust around “baby twin” stars. Gas motions supplying materials to the twin were also identified. These results unveil for the first time, the mechanism of the birth and growth of binary stars, which are ubiquitous throughout the Universe. The study was published on November 20 in The Astrophysical Journal.

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Fig 1. Gas and dust disks around L1551 NE spotted by ALMA. Credit: ALMA (ESO/NAOJ/NRAO) / Takakuwa et al.

Stars form in interstellar clouds of molecular gas and dust. Previous studies of star formation focused primarily on single stars like the Sun, and a standard picture of single star formation has been established. According to this picture, a dense gas condensation in an interstellar cloud collapses gravitationally to form a single protostar at the center. Previous observations have found such collapsing gas motions feeding material toward the central protostars.

Compared to single star formation, our understanding of binary star formation has been limited, even though more than half of stars with a mass similar to that of the Sun are known to be binaries. It is thus crucial to observe the physical mechanism of binary formation to obtain a more comprehensive understanding of star formation. Theory suggests that a disk surrounding a young binary will feed material to the central “baby twin” in order for them to grow. While recent observations have found such disks (known as “circumbinary disks”), it was not possible to image the structure and gas motions because of the insufficient imaging resolution and sensitivity.

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Fig 2. Comparison of the disks in simulation and observation. The right panel shows the disk image simulated with ATERUI, and the left panel the real ALMA image. Credit: ALMA (ESO/NAOJ/NRAO)/ Takakuwa et al.

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