Earthlike planet in Gliese 581 system?

[okiscopey (Mike)]

http://news.bbc.co.uk/2/hi/science/nature/6589157.stm

Astronomers have found the most Earth-like planet outside our Solar System to date, a world which could have water running on its surface.

The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra.


Scientists made the discovery using the Eso 3.6m Telescope in Chile.
They say the benign temperatures on the planet mean any water there could exist in liquid form, and this raises the chances it could also harbour life.


"We have estimated that the mean temperature of this 'super-Earth' lies between 0 and 40 degrees Celsius, and water would thus be liquid," explained Stephane Udry of the Geneva Observatory, lead author of the scientific paper reporting the result.

[StarKers]

Does this mean we have somewhere to go when this planet dries up?

[Ric]

A very interesting article.

At 20.5 light years we better start planning the trip now, we might need more than the cut lunch and a thermos.

Cheers

[ballaratdragons (Ken)]

'The Goldilocks Zone'?

Scientists come up with some strange terms!

[Ric]

I got a good chuckle out of that Ken, it's good to see Astronomers with a sense of humour.

Cheers

[[1ponders] (Paul)]

If it has oceans, imagine the tides it must get with a 15 earth mass planet between it and it's sun. With this planet only having a 13 day year there would be hardly spittin' distance between it and the 15 masser.

It would be a stange planet though. That close to it's paretn star it is most probably tidally locked like our moon. Although the other large inner planet may throw that out of whack now and then

If there is life there it may only be able to survive near the twilight zones.

[DobDobDob (Ron)]

Here is more on the same story, different website: http://www.sciencedaily.com/releases/2007/04/070424204528.htm
I find this a very significant marker on our search for Earth II.

Of course there will be other better candidates as time passes, but one significant factor would be the age of the sun that the planet is orbiting, it would logically, need to be a good deal younger than ours, as well as have the propensity for liquid water.

[bojan]

More here
http://en.wikipedia.org/wiki/Gliese_581

[okiscopey (Mike)]

It's mentioned in some reports that this is a variable star. Isn't this a problem for the poor old Earth2-lings?

Looked around for some data on Gliese 581 and found this (definitive?) source, but still no info on the magnitude variability.

http://www.stellar-database.com/Scripts/
search_star.exe?Catalog=Gl&CatNo=58 1

[[1ponders] (Paul)]

Here is the original paper reporting the exoplanet.
http://exoplanet.eu/papers/udry_terre_HARPS-1.pdf

[[1ponders] (Paul)]

A couple more from the observatory that was part of the discovery
http://obswww.unige.ch/exoplanets/gl581.html
http://vo.obspm.fr/exoplanetes/encyc....php?st=Gl+581

[[1ponders] (Paul)]

Here is the original press release to ESO by the discovery group from Geneva

http://www.eso.org/outreach/press-re.../pr-22-07.html

[okiscopey (Mike)]

Originally Posted by [1ponders]

Here is the original paper reporting the exoplanet.
http://exoplanet.eu/papers/udry_terre_HARPS-1.pdf

Hmmm. Looks like this variable isn't very variable. This paper reports that Gl 581 varies by less than '6mmag'.

Anyone have any idea what a 'mmag' is? Is it a millimagnitude?!?

[[1ponders] (Paul)]

mmag = millimagnitude

[[1ponders] (Paul)]

It's mentioned in some reports that this is a variable star. Isn't this a problem for the poor old Earth2-lings?

It depends on the type of variablility. For this type of star it could not be any of the catastrophic large scale variability scenarios that occur with more massive stars. It might be a problem if it was a flare star, which is probably the only type of catastrophic variability available to a M class star.

It may be as simple as the type of variability that afflicts our own sun. (Yes our sun comes under the category or a variable star). Sunspots cause our sun to vary it's solar flux over time which is classed as a form of variability.

So it just might be nice and cosy there after all. Except for my point above about if it is tidally locked. That could make life unpleasant.

[middy]

Originally Posted by StarKers

Does this mean we have somewhere to go when this planet dries up?

I hear because of the current water restrictions in QLD, the people of Brisbane will be on the first ship to leave ......... along with all the hairdressers and telephone sanitizers.

[DobDobDob (Ron)]

Originally Posted by middy

I hear because of the current water restrictions in QLD, the people of Brisbane will be on the first ship to leave ......... along with all the hairdressers and telephone sanitizers.

Not to mention the housemates from Big Brother

[casstony]

It's always nice to see 'space news' broadcast in the TV news. It might excite a few people to think more broadly about where we live and how precarious our existence is.

[StarKers]

I don't know how to waste water. I have one tank, and keep an eye permanently on the water level.

We could probably do alright if we transport the offenders who waste water, along with Peter Beatie and the slow acting polies from Canberra on the First Fleet.

[bojan]

We would be 2.22 times heavier on that planet...