Skip to comments.First habitable Earth like planet outside Solar System discovered
Posted on 04/24/2007 1:41:01 PM PDT by Sopater
Munich, April 24: An international team of astronomers from Switzerland, France and Portugal have discovered the most Earth-like planet outside our Solar System to date.
The planet has a radius only 50 percent larger than Earth and is very likely to contain liquid water on its surface.
The research team used the European Southern Observatorys (ESOs) 3.6-m telescope to discover the super-Earth, which has a mass about five times that of the Earth and orbits a red dwarf already known to harbour a Neptune-mass planet.
Astronomers believe there is a strong possibility in the presence of a third planet with a mass about eight times that of the Earth in the system.
However, unlike our Earth, this planet takes only 13 days to complete one orbit round its star. It is also 14 times closer to its star than the Earth is from the Sun.
However, since its host star, the red dwarf Gliese 581, is smaller and colder than the Sun and thus less luminous the planet lies in the habitable zone, the region around a star where water could be liquid!
We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid, said Stéphane Udry from the Geneva Observatory, Switzerland and lead-author of the paper in the journal Astronomy and Astrophysics.
Moreover, its radius should be only 1.5 times the Earths radius, and models predict that the planet should be either rocky like our Earth or covered with oceans, he said.
Liquid water is critical to life as we know it and because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X, added Xavier Delfosse, a member of the team from Grenoble University, France.
According to the research team, the host star, Gliese 581, is among the 100 closest stars to us, located only 20.5 light-years away in the constellation Libra (the Scales).
The star has a mass only one third that of the Sun. Such red dwarfs are at least 50 times intrinsically fainter than the Sun and are the most common stars in our Galaxy. Among the 100 closest stars to the Sun, 80 belong to this class.
Red dwarfs are ideal targets for the search for such planets because they emit less light, and the habitable zone is thus much closer to them than it is around the Sun. Any planets that lie in this zone are more easily detected with the radial-velocity method, the most successful in detecting exoplanets, said Xavier Bonfils, a co-worker from Lisbon University.
“orbits a red dwarf”
I can see how that’d make it easier to find, but wow, how unlikely is it that something the right size and composition would also be in the star’s itsy bitsy habitable zone.
A red dwarf's solar wind is pretty pathetic compared to the sun's
Tides are something with which I have a fair familiarity. I seem to remember that there is a way that moons can be detected on faraway planets like this one, though it’s not mentioned in the article.
You’re right about the angular momentum. THe planet’s round though. So I’d expect the order of magnitude for that kind of a correction to be smaller by less than 2. Earth’s is ~0.3% at the equator.
There could be a good basis for these things. We roughly know what mass the star is since we know it’s luminosity and its distance. In turn, we can tell what the planet’s mass is by the motion of Gleise around their mutual centers of gravity. The orbital period is simply the time it takes for the star to make a single complete “wobble.”
This takes a bit of computation since the wobble we want to measure has to be sifted out from the larger effects of the larger Neptune class planet, but it can be done without too much hassle. Since we know the distance from the star, the star’s energy output, and the planet’s mass, we can say whether or not the world lies in the “habitable zone” wherein liquid water can exist in an equilibrium environment.
The presence of water is suspected on account of current models of the growth and evolution of planetary systems. We won’t know for sure until one of the proposed next-generation spectrometers is launched, but that seems more likely now that we have a definite target, and one that’s pretty close by to boot!
That is, of course, providing there aren't any illegals there. LOL!
A space shuttle would leave too big of a carbon footprint. Better if we send him in a one man Mercury capsule.
Note to everyone. Gravitational force scales with radius as well as mass.
F = G(m1)(m2)/R^2
The force experience there by someone on the new world with mass M is
F1 = G(M)(5m(Earth))/(1.5R(earth))^2
The force experience here on earth is
F2 = G(M)(m(Earth))/(R(earth))^2
The ratio of these two forces is:
F1/F2 = 5/(1.5)^2 = 2.22..
So a 150 lb man here would weigh about 333 lb there. It’s a big difference, it would certainly be inconvenient for us, but it wouldn’t be lethal for a wide variety of earthborn species.
Also, a planet so close to it’s sun would be tidally locked, i.e. the same part of the planet would always face it, much like the same side of the moon always faces Earth (this is true for most moons of every planet in the solar system) therefore making one side of the planet super-hot and the other ice cold.
So we have to round up potential (almost prenatal) NFL offensive lineman to send there?
Maybe, maybe not. Mercury isn’t tidally locked, and it’s a lot closer to the Sun than this planet is claimed to be. The planet isn’t likely to be a pleasant place though. With liquid water on the surface and such close proximity to the host star, there’s a strong chance that the planet will have tidal action in the oceans driven by the star itself. The Earth does experience tidal effects in the seas due to our own Sun, but they are largely invisible due to the much stronger tidal pull of our moon. Since the tidal pull of our own sun is 46% the strength of the tidal pull of our moon, one can only imagine the tidal pull a star would exert on the liquid surface of a planetary body 14 times closer.
It’s true that X-rays and tidal locking would be a huge problem for life on a rocky planet but aquatic life might survive with water to provide some protection from the radiation and also to serve to spread the heat around.
I will take your word for it LOL!
For what it’s worth, 120 miles is 20.4 light years.
Assuming current technolgy, a massive effort to build a nuclear-pulse engine and space craft(probably could be done in 10-15 years time, if we REALLY got after it) -— say by a benevolent dictator of USA that was really into space.
I bet a voyage would take 30 years one-way, our relativistic time, (5 years to accellerate, 5 to decellerate, 20 years or so at 3/4 speed of light).
Let’s go visit and find out.
I’m thinking women would really need bed rest during the last trimester.
A newborn baby! A mere 32lbs!
Red Sun? Greater gravity? Might have to be kinda strong huh to get around?
.....models predict that the planet should be either rocky like our Earth or covered with oceans,...
Fifty fifty chance . The man could recall that earth has both
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