Worlds With Multiple Suns Abundant

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Worlds With Multiple Suns Abundant
Staff Writer
SPACE.com
Thu Jan 12, 10:00 AM ET

WASHINGTON, D.C.--Two new studies suggest that planet formation around multiple star systems may be more common than previously thought.

The findings were presented here at the 207th meeting of the American Astronomical Society.

One study, lead by doctoral student Deepak Raghavan from Georgia State University, confirmed that 29 planet-harboring star systems also contained a second star; three actually had two companions and were triple star systems.

Raghavan and his team combed through archived star data to identify 131 star systems with planets that scientists had previously suspected of having companion stars. They then used telescopes at the Cerro Tololo Interamerican Observatory in Chile to confirm the results and to also look for new systems with multiple stars.

The group found one previously unknown stellar companion around HD 38529, a star known to have planets but until now was thought to be a single star system.

Computer agrees

Theorists have long wondered if such setups could occur, given the complex gravitational situations involved.

But in a separate new computer modeling effort, Alan Boss at Carnegie Institution's Department of Terrestrial Magnetism (DTM) and colleagues determined that gas-giant planets like Jupiter can indeed form in binary star systems in much the same way that planets form around single stars such as the Sun.

"We tend to focus on looking for other solar systems around stars just like our Sun," Boss said. "But we are learning that planetary systems can be found around all sorts of stars."

It was once thought that the strong gravitational forces from stars in double star systems interfered with each other's ability to form planets.

But the new theoretical model by Boss' team shows that if the gravitational force from one star in a double star system is weaker than the other, then gas-giant planets can form in much the same way as they do around single stars.

In these theoretical systems, the whirling disks of dust and gas that form the starting material for planets could remain cool enough to grow into solid cores and form gas planets with masses thousands of times that of Earth.

In this line of thinking, the planet-forming disk condenses into dense spiral arms, within which the dust and gas clump together to eventually form planets. The process is believed to require less than 1,000 years--much shorter than previously thought by many astronomers, though Boss has for years now been modeling similar brief time spans for giant planet formation around single stars.

Other Earths?

The model also suggests that there would be plenty of room for Earth-like planets to form close to the central star after the gas giants finished developing.

"This result may have profound implications in that it increases the likelihood of the formation of planetary systems resembling our own," Boss said.

That's because binary star systems tend to be rule rather than the exception in our galaxy. It's estimated that up to two out of every three stars in the Milky Way are part of multiple star systems, many of them binary. If such systems can shelter both outer gas giant planets as well as inner Earth-like planets, then the odds of finding habitable planet in distant star systems would be increased by roughly threefold.

The team's findings will also be published in an upcoming issue of the journal Astrophysical Journal.

There are many stars in the galaxy, there are more double star systems or multiple star systems; even they should have some planets around them too. It does make sense that they to should have some planets in the end.

Interesting, when I saw the three suns in Star Wars I had thought it was just science fiction... I guess I always assumed that if two stars were in such close vicinity to each other, their gravitational force would make them collide. Now I know better, thanks!

This is really nothing new to science-fiction fans. Example:

In 1941 Dr. Issac Asimov, in his groundbreaking story "Nightfall," posited an Earth-type planet in a multi-star solar system. Six suns graced this planet. However, every twenty thousand years, all the stars went into eclipse, bringing the nightfall of the title. On the occasion of previous eclipses. civilizations that had developed on the planet disintegrated as its inhabitants went insane.

Also, any reader of science fiction or science fact knows that our own solar system nearly was a double-star system. Jupiter is what astronomers call a proto-star, lacking only sufficent mass and energy to become a sun.

Boy, I can sound pedantic, can I?

I thought it was common knowledge that multiple starsystems existed. After all the Alpha Centauri and Proxima centauri star system is only 4.22 light years away from our own solar system and that is a starsystem with two stars.

I knew that planets could form in multiple star systems because I have read about this possiblity a few times before. I have also read a article about a earth like planet existing in a multiple star system. I think the possiblity is there and perhaps people could be able to look at these star systems for possible life but I don't see this as the most likely situation. I wonder how the planet will be effected by having two stars around it and how it would manage to stay at a steady enough temperature in a safe distance away from suns. I also wonder if the effect of the graverty may some how stop the planets from rotating( I havn't researched this particular point at all) and I wonder if that could effect the chances of habbitable life in a negative way.

So all in all this is not new news but it sounds like alot of people didn't know it so it is a good thing to learn some thing new and its even better when its about some thing interesting like space rather than boring movies and stuff.

I look forward to seeing what developments to do with science and space descovery happen with in the next 50 years.

I'm sure just about everybody here remembers the scene from the original Star Wars where Luke is looking at Tatooine's twin suns setting, but in reality, a planet with even that much temperature stability is improbable. Such a planet's orbit would be so eccentric that it would be very close and then very far from a star at times depending on where the planet is at in it's orbit around the stars as well as where the stars are at in their orbit around each other.

Some double star systems could be many AUs apart in the 10s, 100s, even in the end 1000s, of AUs. So even finding maybe a earth like planet around a double star system is not so far fetched than what some may think in the end.