Earth. A new study shows that other stars could have up to seven Earth-like planets if there was no gas giant like Jupiter.
This is the conclusion of a study led by UC Riverside astrobiologist Stephen Kane, published this week in the United States. Astronomical magazine.
The search for life in space usually focuses on what scientists call a “habitable zone,” an area around a star in which the orbiting planet could have liquid ocean oceans – a state of life as we know it.
Kane studied a nearby solar system called Trappist-1, which has three Earth-like planets in its habitable zone.
“This made me think about the maximum number of habitable planets that a star can have and why our star has only one,” Kane said. “It didn’t seem fair!”
His team created a model system in which they simulated planets of various sizes orbiting their stars. The algorithm generated gravitational forces and helped test the interaction of planets over millions of years.
They found that it is possible for some stars to support up to seven, and that a star like our sun could potentially support six planets with liquid water.
“More than seven and the planets are too close together and destabilize the orbits of others,” Kane said.
So why does our solar system have only one habitable planet if it can support six? It helps if the movement of the planets is circular rather than oval or irregular, thus minimizing any close contact and maintaining stable orbits.
Kane also suspects that Jupiter, which weighs two and a half times the mass of all the other planets in the solar system, has limited the habitability of our system.
“It has a big impact on the habitability of our solar system because it is huge and disrupts other orbits,” Kane said.
Only a handful of stars are known to have more planets in their habitable zones. Moving forward, Kane plans to search for more stars surrounded exclusively by smaller planets. These stars will be the main targets for direct imaging with NASA telescopes, such as at Jet Propulsion Laboratory’s Exoplanet Visiting Observatory.
Kane’s study identified one such star, Beta CVn, which is relatively close to 27 light-years away. Because it does not have a planet similar to Jupiter, it will be included as one of the stars checked into more habitable zones of the planets.
Future studies will also include the development of new models that investigate the atmospheric chemistry of planetary habitable zones in other star systems.
Projects like these offer more than new paths in the search for life in space. They also provide scientists with an insight into the forces that could one day change lives on our planet.
“While we know that the Earth has been habitable for most of its history, many questions remain about the evolution of these favorable conditions over time and the specific factors behind these changes,” Kane said. “By measuring the properties of exoplanets, whose evolutionary pathways may be similar to our own, we gain an overview of the planet’s past and future – and what we need to do to maintain its habitability.”
According to new estimates, up to six billion Earth-like planets in our galaxy
Stephen R. Kane et al., Dynamic Habitat Packaging: The Case of Beta CVn, The Astronomical Journal (2020). DOI: 10.3847 / 1538-3881 / ab9ffe
Provides University of California – Riverside
Citations: A Surprising Number of Exoplanets Could Be Life (2020, July 31), acquired on July 31, 2020 from https://phys.org/news/2020-07-exoplanets-host-life.html
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