Researchers map out regions where exoplanets can exist within triple star systems

June 13, 2018, Wits University
Researchers map out regions where exoplanets can exist within triple star systems.
Credit: Wits University

Researchers from the University of the Witwatersrand in South Africa (Wits) and the University of Grenoble Alpes in France have mapped out regions where exoplanets can exist within triple star systems.

The study, led by Franco Busetti, at the School of Computer Science and Applied Mathematics at Wits, shows that there are large stable areas where exoplanets can indeed exist in both binary and triple star systems. A binary star system is where two are in around each other, while a triple system is when a third star orbits around both the stars in a binary system.

"Because of the complex dynamics between these stars and planets, it was previously thought improbable that many planets would have stable orbits in these regions," says Busetti.

As part of his Ph.D., Busetti worked with Hervé Beust of the Institute of Planetology and Astrophysics at the University of Grenoble Alpes in France, and Charis Harley at Wits. Together they ran over 45 000 high-performance computer simulations over a three-year period, examining all the possible combinations of orbits, dimensions, masses and other variables of a series of 24 different stellar combinations. They showed that it was indeed possible for exoplanets to exist within large regions of these systems. They also mapped out areas where it was most likely that these planets could be found.

"We ran the simulations for periods ranging from 1 million to 10 million years, in order to see if the systems are stable over very long periods. If a planet is ejected from that system during this time, it is not stable."

Exoplanets are planets that exist outside of our Solar System. Of the 3700 exoplanets that have been found to date, less than 40 are in triple star systems. Busetti says this is partially because very few triple systems have been searched.

"The analysis shows that most configurations had large enough stable regions for planets to exist. Many of these areas are actually very habitable for planets."

The research has been submitted for consideration to be published in the journal Astronomy & Astrophysics. Busetti has been invited to present this research at the 232nd Meeting of the American Astronomical Society in Denver, Colorado, in June 2018. The work could assist in guiding future observational campaigns to discover planets in triple star systems.

"It could assist in selecting suitable candidates for a survey of such systems and guide the observational searches for them," says Busetti. "The geometry of the stable zone indicates not only where to look for but how to look."

The results can also be used by other astronomers to quickly determine the feasibility of their initial observations of orbits.

Explore further: AI beats astronomers in predicting survivability of exoplanets

Related Stories

The impossible triple star KIC 2856960

September 9, 2014

There's news this week of an "impossible" triple star system recently discovered by astronomers. One that "defies known physics." Needless to say, there's no need to abandon physics quite yet.

Planets around other stars are like peas in a pod

January 9, 2018

An international research team led by Université de Montréal astrophysicist Lauren Weiss has discovered that exoplanets orbiting the same star tend to have similar sizes and a regular orbital spacing. This pattern, revealed ...

Is our solar system weird?

July 18, 2014

Is our Solar System normal? Or is it weird? How does the Solar System fit within the strange star systems we've discovered in the Milky Way so far?

Planet with triple-star system found

April 1, 2016

A team of researchers working at the Harvard-Smithsonian Center for Astrophysics has announced the finding of a triple-star system—one that also as has a stable orbit planet in it. In their paper published in The Astronomical ...

Astronomers bring a new hope to find 'Tatooine' planets

July 16, 2015

Sibling suns – made famous in the "Star Wars" scene where Luke Skywalker gazes toward a double sunset – and the planets around them may be more common than we've thought, and Cornell astronomers are presenting new ideas ...

Recommended for you

Meteorite source in asteroid belt not a single debris field

February 17, 2019

A new study published online in Meteoritics and Planetary Science finds that our most common meteorites, those known as L chondrites, come from at least two different debris fields in the asteroid belt. The belt contains ...

Diagnosing 'art acne' in Georgia O'Keeffe's paintings

February 17, 2019

Even Georgia O'Keeffe noticed the pin-sized blisters bubbling on the surface of her paintings. For decades, conservationists and scholars assumed these tiny protrusions were grains of sand, kicked up from the New Mexico desert ...

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (2) Jun 13, 2018
I realize that this research is still in it's infancy and the development of sophisticated instruments needs to continue.

But claiming 'stability' seems rather dubious. A few million or even few tens of millions of years of planetoid survival is rather ephemeral in the greater scheme of things.

Questions that need to be answered are: How old are these stars? How stable are their binary orbits?

How well developed are their proto-planetary disks?
Would not the aggregate disks be disrupted before planetary formation is possible?

After a few tens of millions of years, what happens next?
In the article it was implied that these planets could eventually be ejected from these multiple star systems.
Is this a predictable event? That we should be watching for?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.