IS ANYONE THERE?: This artist’s impression shows the newfound potentially habitable alien planet HD 40307 g in the foreground, with its host star and two other worlds in the six-planet system also depicted. The atmosphere and continents shown are neither detected nor constrained by the discovery team's observations.
Image: J. Pinfield, for the RoPACS network at the University of Hertfordshire.
Astronomers have detected an alien planet that may be capable of supporting life as we know it — and it's just a stone's throw from Earth in the cosmic scheme of things.
The newfound exoplanet, a so-called "super-Earth" called HD 40307g, is located inside its host star's habitable zone, a just-right range of distances where liquid water may exist on a world's surface. And the planet lies a mere 42 light-years away from Earth, meaning that future telescopes might be able to image it directly, researchers said.
"The longer orbit of the new planet means that its climate and atmosphere may be just right to support life," study co-author Hugh Jones, of the University of Hertfordshire in England, said in a statement. "Just as Goldilocks liked her porridge to be neither too hot nor too cold but just right, this planet or indeed any moons that it has lie in an orbit comparable to Earth, increasing the probability of it being habitable."
HD 40307g is one of three newly discovered worlds around the parent star, which was already known to host three planets. The finds thus boost the star's total planetary population to six. [Video: Super Earth May Have Liquid Water]
Finding new signals in the data
The star HD 40307 is slightly smaller and less luminous than our own sun. Astronomers had previously detected three super-Earths — planets a bit more massive than our own — around the star, all of them in orbits too close-in to support liquid water.
In the new study, the research team re-analyzed observations of the HD 40307 system made by an instrument called the High Accuracy Radial velocity Planet Searcher, or HARPS.
HARPS is part of the European Southern Observatory's 11.8-foot (3.6 meters) telescope at the La Silla Observatory in Chile. The instrument allows astronomers to pick up the tiny gravitational wobbles an orbiting planet induces in its parent star.
The researchers' new analysis techniques enabled them to spot three more super-Earths around the star, including HD 40307g, which is thought to be at least seven times as massive as our home planet.
HD 40307g may or may not be a rocky planet like Earth, said study lead author Mikko Tuomi, also of the University of Hertfordshire.
"If I had to guess, I would say 50-50," Tuomi told SPACE.com via email. "But the truth at the moment is that we simply do not know whether the planet is a large Earth or a small, warm Neptune without a solid surface."
A jam-packed extrasolar system
HD 40307g is the outermost of the system's six planets, orbiting at an average distance of 56 million miles (90 million kilometers) from the star. (For comparison, Earth zips around the sun from about 93 million miles, or 150 million km, away.)
The other two newfound exoplanets are probably too hot to support life as we know it, researchers said. But HD 40307g — which officially remains a "planet candidate" pending confirmation by follow-up studies — sits comfortably in the middle of the star's habitable zone.
Further, HD 40307g's orbit is distant enough that the planet likely isn't tidally locked to the star like the moon is to Earth, researchers said. Rather, HD 40307g probably rotates freely just like our planet does, showing each side of itself to the star in due course.
The lack of tidal locking "increases its chances of actually having Earth-like conditions," Tuomi said.
See what we're tweeting about
13 Comments
Add CommentCurious...not sure what 'direct imaging' means at 42 light years. But, does the luminosity of the parent star have a big impact? Is it better if the star is more bright or less bright than our Sun?
Reply | Report Abuse | Link to thisThe first thing that struck me was what the gravity would be like on the surface of such a large planet, and how that would affect the evolution a whatever life existed if it does.
Reply | Report Abuse | Link to thisWonder if " Paul " stopped there for a top-up on his eventual encounter with our planet, and subsequent presumed "Guest" status at Area 51.
Reply | Report Abuse | Link to thisTwo planets are reserved for us earthlings.Don't expect that we will be allowed to take over the galaxy ,as implied by Star Trek.
Reply | Report Abuse | Link to thisIt depends on its size and density. If it's big and fluffy enough, surface gravity could be quite confy even with the 7x mass estimation. Other 'perks' on there, like atmosphere, magnetic shielding, etc. would probably not be as nice, though, for fluffy planets. Then again, it's not like we've seen tons of these, right?
Reply | Report Abuse | Link to thisSuper - Earth - bla bla bla .....imaginations at work, we dont know even what is life in its fundamental reality
Reply | Report Abuse | Link to this*theatrical sigh*
Reply | Report Abuse | Link to thisalan, you are clearly mentally unstable. Please stop commenting here and trying to convince us of the veracity of Nostradamus.
Excellent article. Now we just need warp drive and the Enterprise, and we can go find Ricardo Montalban in outer space.
Reply | Report Abuse | Link to this(sorry, I'm a big Khan fan).
Seriously, though, wouldn't it be possible for the new planet to be a small gas giant, and for it to have a habitable moon? That would be one heck of a find, and more likely to be habitable.
Does tidal locking of a planet or satellite means lack of spinning? Does'nt moon spins around its axis while revolving around earth due to tidal locking with earth?
Reply | Report Abuse | Link to thisYes, but one side of the moon always faces Earth, while the dark side always faces away. In the same way, tidal locking would keep a planet always facing its sun in the same way.
Reply | Report Abuse | Link to thisIn case of Moon, only one side always faces earth since spin ( rotation) period of Moon around its axis and orbital period around earth are same at about 29 days. In case of an exo planet also, with only one side facing its star, are spin ( rotational) period and orbital period same? How equality of spin period and orbital period linked to tidal locking? What does the term "tidal locking" signifies exactly?
Reply | Report Abuse | Link to thisI'm assuming the "two" planets you speak of are Earth and Mars. Am I correct? But theoretically speaking it could be three planets if we are able to terraform Venus in the future. Just sayin...
Reply | Report Abuse | Link to thisIntelligent discussion (mostly,) although (a) to b/t/d/geek, as I'm sure you realize, there is no "dark side" of our tidal-locked moon (only a "Far Side, ala Gary Larson) and (b) to r-bozo-V: Yes, Virginia, we DO know what life is "in its fundamental reality": the Chemistry of Replication.
Reply | Report Abuse | Link to thisAnd although it's been quite a while since Copernicus then Darwin then Einstein reminded us that there's nothing special about us or our place in the universe, we still think ethno/geo-centrically as reflexively as we say "dark side." Yes, Newton tells us the intrinsic gravity of a planet EIGHT times that of Earth (a little more massive than HD40307g) would be EIGHT times that of Earth. But there's an "r-squared" in the denominator of that same Universal Law of Gravitation, so for a rock/iron planet of roughly the same average density a Earth, (~5.54 g/cm^3,) one EIGHT times as massive would have EIGHT times the volume or TWICE the radius, hence that mass factor of EIGHT would be divided by FOUR (i.e., TWICE-squared) and the SURFACE gravitational force would be only 8/4=TWICE as great.
Could creatures evolve to handle a perpetual 2gs? I think so, particularly since in the suggested liquid water, neutral buoyancy would make it irrelevant (why whales had to return from land to the ocean to reach their current size.) Even on land, since volume & mass decrease as size-cubed but surface area/musculature decrease only as size-squared, smaller creatures could readily handle double gravity: ants can lift ten times their own weight and birds are flightless at much over Condor-weight for the same reason.
As always, it's all in the numbers.