From RedOrbit and Science News Astronomers Discover Lightest Exoplanet Yet
Astronomers claim to have discovered an exoplanet that is the most similar to Earth in terms of mass than any previously discovered.
Found in the constellation Libra, the planet known as Gliese 581 represents about twice the mass of Earth.
Astronomers have previously identified some 300 exoplanets, but most are much larger than Earth.
“This is by far the smallest planet that’s ever been detected,” said Michael Mayor, from the Geneva Observatory, Switzerland.
“This is just one more step in the search for the twin of the Earth.
“At the beginning, we discovered Jupiter-like planets several hundred times the mass of the Earth; and now we have the sensitivity with new instruments to detect very small planets very close to that of the Earth,” he told BBC News.
Mayor worked alongside an international team of scientists who made the observation using the low-mass-exoplanet hunting device known as the HARPS spectrograph, which is attached to the 3.6 meter ESO telescope at La Silla, Chile.
“The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the ‘habitable zone’ – a region around the host star with the right conditions for water to be liquid on a planet’s surface,” Mayor said in a statement.
“With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet”, said co-author Xavier Bonfils from Grenoble Observatory.
Although the planet passes too close to its star for life to be possible, scientists claim that another planet in the system may be.
Previous observations using the HARPS showed that the host star was known to harbor a system with a Neptune-sized planet and two “super-Earths”.
Gliese 581 d was discovered two years ago with a mass of about seven times that of Earth. It orbits its parent star in 66.8 days, according to astronomers.
“Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” said team member Stephane Udry.
“‘d’ could even be covered by a large and deep ocean – it is the first serious ‘water world’ candidate,” she added.
Sophisticated modern technology allows astronomers to observe exoplanets by studying the tiny wobble in star motion. The discovery of low-mass red dwarf stars like Gliese 581 adds potential of finding other low-mass exoplanets in the habitable zones, scientists said.
“With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” said Bonfils. “The hunt continues.”
“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 – the one around 51 Pegasi,” says Mayor. “The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”
The international team’s findings will be published in the journal Astronomy & Astrophysics.
From Science News:
“The object, a mere 20.5 light-years away, could be as tiny as 1.9 Earths and isn’t likely to exceed twice that amount.”
This diagram shows the position of the four planets in the Gliese 581 system. The newly found, innermost body is Gliese 581 e, the smallest exoplanet yet discovered. The habitable zone (blue region), where water could exist as a liquid, clearly includes the outermost planet, Gliese 581 d.
Ray:
That sure is a wonderful sentiment, isn’t it?
But what happens when someone attacks you? Do you just “say no to war”?
There is a name for those folks: “slaves.”
Better to be the big dog on the block. Then it’s not likely you’ll be attacked.
But what is the size, in solar masses, of the star? What is its power oputput. These planets are all very close to the center.
What is the point of searching for said objects when we have no means to get to them? We should focus on our own backyard first before we go starring off down the road. Heck we cant even get the moon probably anymore.
Also all they do to find these things is study the wobble of the star, so they dont even know if these planets are rocky, atmosphereic or liquid, let alone what types of air, rock or liquid, so the whole “second earth” deal is greatly blown out of proportion. Just because a planet might have near earth like mass, it doesnt make it an earth.
Ralph Couey,
Thanks for the reminder!: click
So what surface temperature would be considered habitable by Hanson and Gore? Per AGW theory, I would guess that it must be about 15 C +/- 2 C. I think that would make for a very small habitable zone!!
Have we discounted the possibility of life (but not as we know it Jim) that does not need water – like silicat based life in a liquid ammonia substrate for example?
“Have we discounted the possibility of life (but not as we know it Jim) that does not need water – like silicat based life in a liquid ammonia substrate for example?”
Yes Phil’s Dad, that possibility was utterly ripped to shreds by Dr. Spock on Star Trek episode 14.
Robert Wood (16:45:20) :
> But what is the size, in solar masses, of the star? What is its power oputput. These planets are all very close to the center.
That’s one thing that makes them easier to locate. Earth-like planets in Earth-like orbits around Earth-like suns are tough to spot so far.
A couple attributes of the close orbit is the the planet would have massive tides, and is likely tidally locked to the star. Hot side, cold side, nicer ring, with a steady wind blowing toward the hot side. Possibly an ice cap that reaches to the top of the atmosphere. No kayakers.
Would be nice to have a weather satellite feed from there.
Smokey, that was a great article in the Onion:
http://www.theonion.com/content/news/al_gore_places_infant_son_in
The very last sentence contained this truth:
“A bold and eye-catching unitard will give Kal-Al, last son of Earth, a formidable tool for protecting his new planet, a power more awesome than any his father could have dreamed of: the power of charisma.”
Which made me wonder… is there even ONE of the screeching banshees of climate doom, who contains a scintilla of charisma, or a hint of the beginning of a real human personality?
Anyone have any candidates?
http://biocab.org/Astrobiology.html#anchor_25
Sorry for posting a link to one of my articles, but on that article I explain what the optimal conditions for the origin of living beings on a given planet could be. Planets more massive than Earth could host living beings on them without any problem if other conditions are satisfied. What astronomers must seek is for stars which aren’t too hot neither too cold, which have planets with water, acetylene, methane and carbon dioxide. A planet with a mass equal to 1.9 the mass of Earth still could be a good candidate to lodge life. The water presence doesn’t guarantee the existence of living beings on any celestial body, but it would increase the possibilities of their existence.
From my conference on Astrobiology:
“Stars which are warmer or colder than the Sun shouldn’t be excluded from the catalogue because they could have planets which would be orbiting at distances where they would be receiving loads of cosmic radiation adequate for life.”
Chris H: Plugging in that the earth is 83 times as massive as the moon, one would make the plausible guess that the earth would have 83^1/3 as strong gravity.
That would be 4.36 times rather than 6 times. There seems to be an additional mass factor- the more massive the object, the denser it is, at least for terrestrial sized planets. Using just the earth and moon as data points, gravity is proportional to mass to the 0.4055 rather than 0.333…
Using those figures for the 1.9 mass planet, 1.9^.4055 = 1.297, not much larger than your original figure.
Alan D. McIntire (17:46:37) :
Chris H: Plugging in that the earth is 83 times as massive as the moon, one would make the plausible guess that the earth would have 83^1/3 as strong gravity.
That would be 4.36 times rather than 6 times. There seems to be an additional mass factor- the more massive the object, the denser it is, at least for terrestrial sized planets. Using just the earth and moon as data points, gravity is proportional to mass to the 0.4055 rather than 0.333…
Using those figures for the 1.9 mass planet, 1.9^.4055 = 1.297, not much larger than your original figure.
Exactly, living beings on a planet with 1.9 Earth’s mass would have no problems. However, it’s not enough to find water and a Sun-like star. We must find all the factors which could make the existence of life a possibility on that planet. Indeed, the discovery of all factors on a planet doesn’t guarantee the emerging and/or existence of living beings on that planet.
Mike Bryant (17:38:36) :
Can someone both be a “screeching banshee” and have “a scintilla of charisma?”
I’ll suggest Kerry Emanuel – http://wind.mit.edu/~emanuel/home.html – seems to handle himself well on interviews and at a Southern New England Weather Conference his spoke at once. I like his book “Divine Wind.”
He’s moderating a bit on his early it’s-all-a-heat-engine stance having seen what El Nino can do to a perfectly good Atlantic Hurricane season, though you probably don’t want him in the same room as Bill Gray still.
Ric,
I believe that Emanuel has changed his views once or twice. He is a thoughtful person who still believes that, perhaps hurricanes will worsen in a warming world. You are correct he is hardly a screeching banshee. He seems more like Lucia, who is thoughtful and uses the scientific method. I think he is more of a lukewarmer, not an alarmist, not a climate doomsayer.
Mike
Stef (12:12:22) and Sunfighter:
Good points. Until we get people’s heads in the real world (e.g. there is no “warp speed”, we’ve got that whole light-speed barrier thing) they will be preoccupied with things like this. Just what has happened to the space program??
Right! I’m off!
Toodles.
I, for one, welcome our carbon depleting, global cooling, Gliesian overlords.
Adam from Kansas (12:25:30) : “…What if the galaxy already has a president named Beeblebrox?”
And it surely does! Gentlebeings, I give you the chief of the Galactic Senate, President Beeblebrox:
http://www.swissinfo.ch/xobix_media/images/keystone/2007/keyimg20071016_8319949_0.jpg
Where’s Prot these days? Is he on K-Pax or back here?
Smokey (16:43:23) :
“Better to be the big dog on the block. Then it’s not likely you’ll be attacked.”
This is called being a bully. And that is exactly what the majority of people in the rest of the world think of the Americans, and even more after having a bully-in-chief as president.
And now we’ve got another volcano blowing its top (Galapagos).
The Earth is just being so unfaithful to the Alarmists.
Thanks for all the replies about gravity!!
Ray (20:00:31) :
Smokey (16:43:23) :
“Better to be the big dog on the block. Then it’s not likely you’ll be attacked.”
This is called being a bully. And that is exactly what the majority of people in the rest of the world think of the Americans, and even more after having a bully-in-chief as president.
No, it’s called being the big dog on the block, Ray. It makes being a bully unnecessary, and it makes it a lot less likely you’ll be attacked. Or are you an umbrella-waving, peace-in-our-times wuss? Didn’t work in 1938, and it’s not going to work today anywhere but in your mind.
MC (13:31:48) :
For the sake of brevity only may I suggest instead: Damn Gore and Hansen!!!
George E. Smith (15:53:39):
The search for ET intelligent life is based on the false assumption that intelligence brings superior survivability.
In reality, Intelligence is just Mother Nature’s latest gimmic in the search for survival; and so far it looks like a loser.
I disagree with those who think that intelligence brings a superior survivability. Intelligence is not privative of human beings. Besides, the evolution of intelligence is stochastic because it exhibits microstates which order and trajectories are algebraically unpredictable. So we cannot model the evolution of intelligence.