Most Stars in the Universe Host an Alien Planet

By Bill Andrews | March 4, 2014 12:30 pm

red dwarf and planet

Fans of exoplanets have had an exciting few days. First the long-awaited Kepler results were announced, confirming over 700 new worlds outside our solar system. Exciting! That was tempered just a day later, however, by the news that many of the “super earths” astronomers have discovered over the years — worlds larger than Earth, but smaller than Neptune — may in fact be inhospitable, even within their stars’ habitable zones.

But the latest exoplanet news buoys hopes of off-Earth habitability: a new study indicates that potentially habitable exoplanets are much more common that we’d thought.

The Odds Are Ever in Your Favor

The study authors, an international team of astronomers, combined and analyzed existing data from two planet surveys run by the European Southern Observatory: HARPS (High Accuracy Radial Velocity Planet Searcher)  and UVES (Ultraviolet and Visual Echelle Spectrograph). By applying advanced statistical techniques to the data, the researchers discovered that a specific kind of star called a red dwarf is extremely likely to host at least one low-mass exoplanet (less than 10 times Earth’s mass). Scientists had expected planets to be plentiful throughout the cosmos, but at least one around every red dwarf turns out to be quite a pleasant surprise, since red dwarfs are particularly abundant — some estimates say at least three quarters of all the stars in the universe are red dwarfs.

But that’s not all: It also turns out that nearly a quarter of low-mass, red dwarf exoplanets orbit within their star’s habitable zone. So, basically, if you pick 16 random stars, odds are that about 12 should have at least one low-mass planet in orbit, and three of those should be potentially habitable. Not bad, considering exoplanets were still purely hypothetical just 25 years ago. The study is forthcoming in the Monthly Notices of the Royal Astronomical Society.

Bonus Exoplanets

As if that weren’t enough, the paper also announced the discovery of 8 new exoplanets (3 of them in their suns’ habitable zones). All orbit red dwarfs relatively nearby Earth, 15 to 80 light-years from the sun, and have orbital periods (i.e., years) ranging from two weeks to nine years. The study also confirmed the existence of two previously suspected exoplanets, and announced 10 new possible planets that need more study before they can be confirmed.

All of which points to a fruitful new focus for exoplanet hunters. With their increasingly powerful instruments and analyzing techniques, astronomers’ attention to red dwarf systems is sure to go up, along with the official exoplanet count. And, while these findings don’t necessarily guarantee we’ll end up finding a habitable planet, in a place as big as space, it always helps to know where to look.

Image credit: D. Aguilar/Harvard-Smithsonian Center for Astrophysics

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: exoplanets
  • coreyspowell

    Running the statistics:

    There are 7 red dwarfs within 10 light years of home, so there is a good chance of a habitable super-Earth circling one of the very nearest stars.

    Going the other way, there are about 200 billion red dwarfs in the Milky Way. If 1/4 of them have habitable planets, that is 50 billion potential places for life–in our galaxy alone.

    • Walter Savage

      Since our home star, solar is not a red dwarf, what`s the point of searching the belts of red dwarfs for habitable planets when we should be looking for solar like- stars?

      • coreyspowell

        Red dwarfs are vastly more abundant than G-type stars like our sun. If planets around red dwarfs could support life–and the current thinking is that they could–then most of the potentially habitable worlds exist around red dwarfs as well. As Dimitar Sasselov says, “Earth may be common, even though the sun is not.”

        Furthermore, there are a number of reasons why it is much easier to study planets around red dwarfs than around bigger, hotter, sunlike stars. Since we know very little about how life got started here, if it exists on other worlds, and if so what forms it might take–the best approach is to look and see. Red dwarf planets may be the best place to start.

        • melitagnm105

          My Uncle Caleb just got red Ford Focus ST by working off of
          a computer. try this J­u­m­p­9­9­9­.­ℂ­o­m

    • symbolset

      We will find that *all* of the stars within 10 light years of home have bodies that can sustain life in them, and they already have life on them. Even in the debatable case that life’s genesis started on Earth, Earth’s life has polluted all these stars.

  • symbolset

    It has been a huge week for the Drake equation.

  • http://blogs.discovermagazine.com Victor Freitas

    Discover technology? We didn’t discover technology, we created it… Definition from wikipedia: “is the making, modification, usage, and knowledge of tools, machines, techniques, crafts, systems, and methods of organization, in order to solve a problem…”

    Now tell me how do you discover that?

    On aliens visiting earth: well there’s a lot you could say about that but the first one is on physics… remember, if we think that the nearest habitable planet might be at 10 light years away, it would take us 10 years traveling at light speed to get there, now, traveling at light speed as organic creatures as we are is (at the moment) impossible… You would be torn apart while on acceleration… But still let’s imagine that there’s some technology we don’t now about that could overcome that and a lot of other troubles, and some alien civilization had it. Don’t you think that that technological superior race could mask (I don’t mean a literal mask) themselves so we wouldn’t know they would be here… I mean i could go on with this… but the only real thing we know is: we haven’t seen them yet! At least not me!

    As for the future… wow… if we don’t kill ourselves first, that would be the most fantastic thing to see: where we’re heading to…

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