10.5 Light Years

[JudgeKing]

Epsilon Eridani might contain Earth-like planets

WASHINGTON - For the first time, astronomers think that they've found evidence of an alien solar system around a star close enough to Earth to be visible to the naked eye.

They say that at least one and probably three or more planets are orbiting the star Epsilon Eridani, 10.5 light-years - about 63 trillion miles - from Earth. Only eight stars are closer.

The host star, slightly smaller and cooler than our sun, is in the constellation Eridanus - the name of a mythological river - near Orion in the northern sky.

Epsilon Eridani is much younger than the sun, about 850 million years old compared with 4.5 billion years for our system.

"This really is a system like our solar system was when it was five times younger than it is now," said one of the discoverers, Massimo Marengo , an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "It's like a time machine for our solar system."

"This system probably looks a lot like ours did when life first took root on Earth," said Dana Backman , of the SETI Institute in Mountain View, Calif. , the lead author of a report to be published Jan. 10 in The Astrophysical Journal .

SETI chose Epsilon Eridani as one of the first targets in its long - but so far vain - search for signs of extraterrestrial intelligence in 1960.

The suspected planets are too far away to be detected directly, so their presence has to be inferred by indirect measurements. Their star is so near, however, that some astronomers think that they may be able to see its planets with better telescopes within the next decade.

One of the planets, a gas giant 1 { times heavier than Jupiter, was discovered in 2000 by Barbara McArthur , an astronomer at the University of Texas in Austin . She measured the slight wobble in the star's position as the planet swung around it. Further observations by the Hubble Space Telescope in 2006 confirmed its existence, McArthur said at the time.

Now Backman's team has deduced the presence of at least two more planets, after space- and ground-based telescopes separately revealed two belts of rocky asteroids and an outer icy ring circling Epsilon Eridani.

The inner asteroid belt is about 280 million miles from its host star, the same distance as our own ring of asteroids orbiting between Mars and Jupiter. The second belt is about the same distance as Uranus is in our system.

Finally, a wide, third ring of icy objects extends billions of miles beyond Epsilon Eridani, resembling the so-called Kuiper Belt of mini-planets outside Pluto.

In 2002, Alice Quillen , an astronomer at the University of Rochester in New York state , reported that unusual clumps of material in the outer ring probably indicated the presence of a Saturn -size planet in a Pluto-like orbit. Her finding hasn't been confirmed, but "I still think there is a planet out there of this size," Quillen said in an e-mail.

According to Marengo, the gaps between these belts were created when clouds of dust and rocks consolidated into planets, as happened in the early days of our solar system. He likened the process to the formation of Saturn's famous rings, which are separated by spaces cleared out by little moons.

"The easiest way to explain the gaps is to say there are planets there," Marengo said. "It's the same way as the rings of Saturn are kept stable by the moons of Saturn ."

"I think these rings are probably telling us about how systems clear out after planets have formed," Quillen said. "It's pretty exciting to catch such a nearby system in this critical stage."

Marengo raised the possibility that more Earthlike planets might exist in the space between Epsilon Eridani and the inner dust ring.

"The inside belt is cleared, like in our solar system," he said. "There could be terrestrial planets inside, but we can't detect them yet."

What do you think? Score 1 for Babylon Five.

[Mark]

Isn't that also known as the Vulcan system?

[JudgeKing]

Isn't that also known as the Vulcan system?

Vulcan is sixteen Light Years away, not 10.5 Light Years away.

[Teaos]

Yeah read this somewhere the other day. They're finding planets all the time at the moment.

[Sionnach Glic]

Awesome. Hopefully there's someone look back at us.

[stitch626]

Interesting. Only thing I don't get is this part:

a gas giant 1 { times heavier than Jupiter

So, as heavy as Jupiter?

[Teaos]

From what I understand planets cant get much bigger than Jupiter, if they were they would ignite into a star.

[Mikey]

Really? Jupiter's pretty friggin' big, but I didn't think it was massive enough for spontaneous fusion. Besides, it comprises a lot of heavier-than-hydrogen elements.

[Captain Picard's Hair]

There are known planets several times as massive as jupiter. The biggest known is over 11 Jupiter masses!

http://en.wikipedia.org/wiki/List_of_st ... ar_planets

[RK_Striker_JK_5]

Awesome. Hopefully there's someone look back at us.

*Looks up into the sky and waves*

[JudgeKing]

Interesting. Only thing I don't get is this part:

a gas giant 1 { times heavier than Jupiter

So, as heavy as Jupiter?

One confirmed jupiter sized planet, and possibly at least one Earth like planet closer to the star. The Gas Giant apparently is about as far away from the star as Jupiter is to our sun. it also helps that the system is only 850 million years old. Please see my diagram below.

Sun
Possible Earth-like planets
Inner Asteroid Belt
Gas Giant
Outer Asteroid Belt

[stitch626]

Ah, thank you. I was just wondering why they said "1 times heavier than Jupiter" when "as heavy as Jupiter" would do.

[shran]

Then they suddenly find a strange peak in the radiation profile of the star and discover a new element. WOuld be awesome if they would name it Quantium 40. It would be even more awesome if a probe, if it ever ets there, or a mission actually starts sweeping scans for the great Machine....

[JudgeKing]

Here's a more accurate version of what the system looks like compared to our own.

[Sionnach Glic]

Interesting. Good find, JK.