Astronomers find planet made of diamond

[applesnail]

Forget the diamond as big as the Ritz - astronomers believe they have found one bigger than Earth.

Orbiting a star that is visible to the naked eye, astronomers have discovered a planet twice the size of our own made largely out of diamond.

The rocky planet, called 55 Cancri e, orbits a sun-like star in the constellation of Cancer and is moving so fast that a year there lasts a mere 18 hours.

Discovered by a US-Franco research team, its radius is twice that of Earth's but it is much more dense with a mass eight times greater.

It is also incredibly hot, with temperatures on its surface reaching 1,648 degrees Celsius.

"The surface of this planet is likely covered in graphite and diamond rather than water and granite," said Yale researcher Nikku Madhusudhan, whose findings are due to be published in the journal Astrophysical Journal Letters.

The study - with Olivier Mousis at the Institut de Recherche en Astrophysique et Planetologie in Toulose, France - estimates that at least one-third of the planet's mass, the equivalent of about three Earth masses, could be diamond.

Diamond planets have been spotted before but this is the first time one has been seen orbiting a sun-like star and studied in such detail.

"This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth," Mr Madhusudhan said.

He said the discovery of the carbon-rich planet meant distant rocky planets could no longer be assumed to have chemical constituents, interiors, atmospheres or biologies similar to Earth.

David Spergel, an astronomer at Princeton University, said it was relatively simple to work out the basic structure and history of a star once you know its mass and age.

"Planets are much more complex," he said.

"This 'diamond-rich super-Earth' is likely just one example of the rich sets of discoveries that await us as we begin to explore planets around nearby stars."

[ballzac]

...its radius is twice that of Earth's but it is much more dense with a mass eight times greater.

Lol

[Thelema]

I don't get it, why is that LOL?

[SunChaser]

This one is actually a very exciting discovery. Since alpha centuari is only just over 4 light years away, it opens up the possibility of us being able to design a probe, which could reach the star system within a reasonable amount of time. Giving us the opportunity to study and actually observe a planet outside of our solar system. Maybe even within our lifetime.

Although, I think it’s still about a 40 thousand year trip with our current technology.

Earth-sized world found next door

Scientists have found an Earth-sized planet circling a neighbour star just four light-years away.

No need to brush up on extraterrestrial etiquette quite yet, however. The planet, which flies around its parent star 10 times closer than Mercury orbits the Sun, which means its surface temperature would be more than 2000°C - far too hot for liquid water to exist on the surface. Water is believed to be necessary for life.

But the newly found planet orbiting Alpha Centauri B, a Sun-like star roughly 25 trillion miles away, could have better-positioned siblings.

"From statistical studies, low-mass planets are very frequently found in multiple systems," says lead researcher Xavier Dumusque, with the University of Geneva in Switzerland.

So far, scientists have only ruled out the possibility of massive planets with orbital periods of 200 days or less around Alpha Centauri B, so that leaves plenty of room for the detection of low-mass planets in the star's so-called "habitable zone" - the distance where water can exist on a planet's surface, says Dumusque.

Planets positioned the same distance as Earth is to the Sun would take 365 days to orbit a parent star of the same type and size as the Sun. Alpha Centauri B's newly found world circles in just 3.2 days, but the star is roughly half the size of the Sun, which puts its habitable zone about where Venus is in our solar system. Venus orbits in 225 days.

Habitable zones

Scientists already have found nearly 800 planets beyond the solar system, about 10 per cent of which are considered low-mass worlds, meaning they are up to about 10 times the size of Earth or smaller.

"Most of the low-mass planets are in systems of two, three, up to six or seven planets, so finding in our closest neighbour one Earth-mass planet ... opens a really good prospect for detecting planets in the habitable zone in the system that is very close to us," says astronomer Stephane Udry, with Geneva University in Switzerland.

"In that sense, it is a landmark," Udry said.

Scientists using Europe's HARPS telescope spent four years trying to ferret out telltale signs of a small planet's gravitational tug on light coming from Alpha Centauri B.

The measurement is difficult because of variations in the star's light caused by other phenomenon, such as flares and magnetic storms, similar to sunspots on the sun.

"Trying to extract a signal that you are interested in when it is in the presence of "noise" - in this case the variability of the star -- is difficult. One has to apply special analysis methods and tricks. The real challenge, in this particular case, was in how to analyze the data," says astronomer Artie Hatzes, with Thuringian State Observatory in Tautenburg, Germany.

"I still have my doubts," Hatzes adds. "Even though there is clearly a signal in the data at 3.26 days, the nature of this is still open to debate."

More data - and more sensitive instruments - will nail down whether the planet actually exists or not, and if it has any siblings.

"Everything we know about this system so far is extremely tantalising," says astronomer Greg Laughlin, with the University of California in Santa Cruz. "This is our backyard and to find out that planet formation did occur there is just extraordinarily exciting."

http://www.abc.net.a.../17/3612356.htm

[ballzac]

I don't get it, why is that LOL?

 

Just the way they present it. It does sound "much more dense" when it's put that way. Sorry, I'm really nit-picking, but I just find it funny how popular media present science. If you take it literally, it puts the density at 12% higher. If you take it to mean "eight times as massive", it puts the density at 0% higher. The figures on wikipedia put it at about 7% higher, so the reality is somewhere in the middle. It's not really an astonishing difference, but I guess it depends on how you mean "much more". It's much less difference than the difference between the density of, say, Earth and Mars.

[cactuscarl]

Um I think they mean 8x as dense ie 800%

[ballzac]

No, I think they do actually mean 8 times more mass, but it wouldn't have sounded so cool to say, "it is much more dense with a density 1.07 times Earth's density."