Astronomers have found a third planet in the Kepler-47 system dubbed Kepler-47d, and according to a new study, it is about seven times larger than Earth.
In the study, a team of astronomers used data from NASA’s Kepler space telescope to detect the new Neptune-to-Saturn size planet, which is orbiting between two previously discovered planets, Kepler-47b and Kepler-47c, said a San Diego State University (SDSU) press release. The team, which published their findings in the Astronomical Journal, revealed cool characteristics of Kepler-47d and how it can reveal more insights on the Kepler-47 system in space.
#SDSU astronomers have discovered a third planet in the Kepler-47 system, securing the system’s title as the most interesting of the binary-star worlds. See details of their research ➡️ https://t.co/IOiNmgxSZ8
Video courtesy: NASA/JPL‑Caltech/T. Pyle pic.twitter.com/yNwzHxmWZp
— San Diego State University (@SDSU) April 16, 2019
“We certainly didn’t expect it to be the largest planet in the system,” William Welsh, an astronomer at San SDSU and co-author, said in the press release. “This was almost shocking.”
The Kepler-47 system is approximately 3.5 billion-years-old and it’s 3,340 light-years from our planet, Space.com noted. One of the system’s stars resembles the sun, while the other star is much smaller and roughly one-third the mass of Earth’s sun.
Back in 2012, Welsh and his team, announced the discovery of the two planets, Kepler-47b and Kepler-47c, circling the two stars. Both planets have two suns in their skies, which are similar to Tatooine, Luke Skywalker’s home planet in the Star Wars movies. These planets were detected by the “transit method,” meaning if the orbital plane of the planet is in a straight line, edged-on as seen from Earth, the planet can pass in front of the host stars, resulting in a decrease in the observed brightness. Kepler-47d was not found earlier because of weak transit signals.
“We saw a hint of a third planet back in 2012, but with only one transit we needed more data to be sure,” said Jerome Orosz, SDSU astronomer and the paper’s lead author, in the press release. “With an additional transit, the planet’s orbital period could be determined, and we were then able to uncover more transits that were hidden in the noise in the earlier data.”
The SDSU team was shocked at the size and location of Kepler-47d, and found that it’s the biggest of the three planets in the Kepler-47 system. Its equilibrium temperature is about 50 degrees Fahrenheit, which is considerable warmer than Kepler-47c (26 degrees Fahrenheit). Kepler-47d also takes 187 days to orbit around its sun.
— Ewan Lawrenson🚀🛰️🌌 (@neucoEwan) April 16, 2019
Now that they’ve located the new planet, astronomers can better understand how the Kepler-47 system operates.
“This work builds on one of the Kepler’s most interesting discoveries: that systems of closely-packed, low-density planets are extremely common in our galaxy,” said University of California, Santa Cruz astronomer Jonathan Fortney, who was not part of the study. “Kepler-47 shows that whatever process forms these planets – an outcome that did not happen in our solar system – is common to single-star and circumbinary planetary systems.”
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