Evidence Builds For First-Ever Exomoon Discovery Orbiting A Planet 4,000 Light Years Away

Friday, 05 October 2018 - 1:08PM
Science News
Friday, 05 October 2018 - 1:08PM
Evidence Builds For First-Ever Exomoon Discovery Orbiting A Planet 4,000 Light Years Away
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NASA JPL/Caltech
Ever since missions like Kepler and K2 launched, the discovery of new exoplanets has become a little less exciting. Sure they're important and any of the confirmed planets could be huge in the future, but there are just so many of them already... And the list is expected to grow exponentially now that TESS is on the job. According to a recent study by astronomers at Columbia University, there is something else to get excited about when it comes to Kepler data: evidence of the first-ever detected exomoon, which is orbiting a planet 4,000 light years from Earth that has a star similar to our sun.

The researchers first spotted the signal using Kepler data, and later confirmed it using NASA's Hubble Space Telescope. The exoplanet that the suspected moon is orbiting is Kepler-1625b, a giant roughly the size of Jupiter first discovered in 2017. "We find evidence in favor of the moon hypothesis, based on timing deviations and a flux decrement from the star consistent with a large transiting exomoon," the co-authors of the research article published in Science Advances wrote in their abstract. They believe that the moon is similar in mass and radius to Neptune, which could explain why it was relatively easy to find using the same method of measuring light flickers used to find exoplanets. "You can make the argument that this is the lowest hanging fruit," lead author Alex Teachey told The Verge. "Because it is so large, in some ways, this is the first thing we should detect because it is the easiest."

Thought the researchers feel confident in their discovery and have worked since July of last year testing their hypotheses, it's important to note that the moon's existence has not been made Facebook official. "We haven't confirmed this is an exomoon," senior project scientist for the Hubble Space Telescope, Jennifer Wiseman said. "We didn't even have a chance to see a full [crossing] of this potential moon, and so we don't have enough information yet to confirm whether this is truly an exomoon. But this has made us even more excited for looking at this system in the future."

More observations are needed before Kepler-1625b's satellite can earn its place in the exomoon history books, and that confirmation could be a key piece of the puzzle that is finding Earth 2. "Now if we know that in other star systems there are not only planets but moons, it gives us other locations to consider for potential habitability," Teachey said.

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