This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: New research led by the University of Michigan is helping set the stage for future observatories to characterize rocky planets outside our solar system, planets that could prove life isn't confined to Earth. The new research represents the most sensitive modern search for giant planets in a nearby binary system—a system with two stars orbiting each other—known as 70 Ophiuchi AB, or 70 Oph AB.
That search, however, didn't discover any large planets. In fact, it did the opposite: With some important caveats, it ruled out planets with the mass of Jupiter and larger. Although that may sound like a letdown, the null result is noteworthy for a few reasons.
For one, there is the record-setting sensitivity the team achieved for the system. Further, despite that sensitivity, the researchers' work, supported in part by NASA, wasn't designed to find smaller planets. That leaves the door open for planets the size of Saturn or smaller within the system's habitable zone.
This is the region where the temperature wouldn't be too hot or too cold for liquid water, a key ingredient for life as we know it, to exist on a rocky planet's surface. This work also represents the latest update to a system with a rich history. In 1855, the British astronomer William Jacob claimed the system had a planet, making 70 Oph AB the first host of an official exoplanet candidate.
Although Jacob's claim itself hasn't held up, the possibility of planets endures. "It's a mix of disappointment and excitement," said Yiting Li, a postdoctoral researcher in the U-M Department of Astronomy. "We're finding out that there isn't a Jupiter-sized planet, but we're also opening the latest chapter on this historic system." While our solar system has only one star, roughly half of the stellar systems in the Milky Way have at least two stars.
These systems are enticing targets for future astronomical studies seeking clues to how planetary systems form, evolve and perhaps even support life. 70 Oph AB is of particular interest given its proximity to Earth. At about 16 light-years away, it's the third-closest binary system to Earth, just behind Alpha Centauri (4.2 light-years) and 61 Cygni (11.4 light-years). Additionally, with this new study, published in The Astrophysical Journal, the orbits of the two stars, 70 Oph A and 70 Oph B, are among the best characterized in the sky.
Extract — continue reading at the source.
