Researchers from the Massachusetts Institute of Technology and Aarhus University have found that 74 small exoplanets orbit their stars in circular rather than eccentric patterns, suggesting that orbital regularity is common. The results could enhance the odds of finding Earth-sized exoplanets hospitable to life:
These 74 exoplanets, which orbit 28 stars, are about the size of Earth, and their circular trajectories stand in stark contrast to those of more massive exoplanets, some of which come extremely close to their stars before hurtling far out in highly eccentric, elongated orbits.
"Twenty years ago, we only knew about our solar system, and everything was circular and so everyone expected circular orbits everywhere," says Vincent Van Eylen, a visiting graduate student in MIT's Department of Physics. "Then we started finding giant exoplanets, and we found suddenly a whole range of eccentricities, so there was an open question about whether this would also hold for smaller planets. We find that for small planets, circular is probably the norm."
Ultimately, Van Eylen says that's good news in the search for life elsewhere. Among other requirements, for a planet to be habitable, it would have to be about the size of Earth — small and compact enough to be made of rock, not gas. If a small planet also maintained a circular orbit, it would be even more hospitable to life, as it would support a stable climate year-round. (In contrast, a planet with a more eccentric orbit might experience dramatic swings in climate as it orbited close in, then far out from its star.)
The team chose 28 stars with multiplanet systems that have been previously observed by the Kepler space observatory, and for which mass and radius had been determined using asteroseismology. Every one of the 74 known exoplanets orbiting those 28 stars were found to maintain circular orbits.
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NASA Retires Kepler Space Telescope
After nine years in deep space collecting data that indicate our sky to be filled with billions of hidden planets - more planets even than stars - NASA's Kepler space telescope has run out of fuel needed for further science operations. NASA has decided to retire the spacecraft within its current, safe orbit, away from Earth. Kepler leaves a legacy of more than 2,600 planet discoveries from outside our solar system, many of which could be promising places for life.
"As NASA's first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the solar system and beyond," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate in Washington. "Not only did it show us how many planets could be out there, it sparked an entirely new and robust field of research that has taken the science community by storm. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars."
(Score: 3, Interesting) by ikanreed on Wednesday June 03 2015, @03:59PM
Live as we know it (probably) can't arise without liquid water.
But I've often wondered, given the power of evolution, if some photosythesizers could adapt to a world that got flung to snowball territory. Like the lichens that manage in northern Canada through the winter, is it possible that living on fractional sunlight is possible at all.
(Score: 2) by Tork on Wednesday June 03 2015, @05:07PM
🏳️🌈 Proud Ally 🏳️🌈
(Score: 2) by takyon on Wednesday June 03 2015, @07:55PM
That's the best chance of finding life on say, Mars/Europa IMO. Get single-celled organisms, fling them off after a meteor hits.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by anubi on Thursday June 04 2015, @06:58AM
Extremophiles" [google.com] may be the word you are looking for.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: -1, Troll) by Anonymous Coward on Wednesday June 03 2015, @04:49PM
any of them near Uranus?
(Score: 4, Insightful) by Covalent on Wednesday June 03 2015, @06:32PM
You can't rationally argue somebody out of a position they didn't rationally get into.
(Score: 2) by takyon on Wednesday June 03 2015, @07:57PM
http://www.theatlantic.com/technology/archive/2012/10/atlast-the-gargantuan-telescope-designed-to-find-life-on-other-planets/263409/ [theatlantic.com]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by cmdrklarg on Wednesday June 03 2015, @07:22PM
Now we need some geek to figure out FTL and we are golden.
The world is full of kings and queens who blind your eyes and steal your dreams.
(Score: 3, Insightful) by frojack on Wednesday June 03 2015, @11:57PM
I'd be happy with some significant percentage of the speed of light.
There are stars we could send probes to at 50% of the speed of light and expect them to arrive, go into scout mode and start beaming back information, just in time for your New born baby's graduation for CalTech. What a job that would be for him/her!!
NASA is looking at faster engines, but their sights are set pretty low:
http://www.space.com/29540-manned-mars-mission-propulsion-technologies.html [space.com]
No, you are mistaken. I've always had this sig.
(Score: 1, Informative) by Anonymous Coward on Wednesday June 03 2015, @07:53PM
Mr. Visiting Graduate Student is incorrect. For multi-planet systems, expecting circular orbits comes from orbital stability arguments. These arguments are very old, but this issue was HUGE in the mid- to late 80s when "chaos theory" (non-linear dynamics) was very popular. If you have one or more planets with high eccentricity, they will interact with the other bodies in resonances such that they will collide, or perhaps eject one or both planets. Either he is not familiar with the history of his field, or he is building their observations up more than is warranted ("nobody expected our results!").
(Score: 0) by Anonymous Coward on Thursday June 04 2015, @12:14AM
Is that where the idea Saturn migrated inward and flung stuff around then migrated back out came from?
(Score: 2, Informative) by Anonymous Coward on Thursday June 04 2015, @03:23AM
I'm not familiar with that idea. However, you can find a lot of good papers from Kuiper (he of the Kuiper Belts notoriety) written in the 50's and 60's, such as this one [nih.gov], or this very readable one [harvard.edu]. This [ias.edu] is a fairly recent talk on the topic, but the issue of the stability of the solar system is centuries old. It was one of the big topics in the 80's to study within the confines of "chaos theory". The question being, is the solar system stable chaotic. We still don't really know.