Earth-Like Planet Can Sustain Life !

[APODman]

"Earth-Like Planet Can Sustain Life
Located in a solar system that parallels our own, the new world could be habitable -- or even inhabited.

A new member in a family of planets circling a red dwarf star 20 light-years away has just been found. It's called Gliese 581g, and the 'g' may very well stand for Goldilocks.

Gliese 581g is the first world discovered beyond Earth that's the right size and location for life.

"Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it," Steven Vogt, professor of astronomy and astrophysics at University of California Santa Cruz, told Discovery News."

(...)

More in: http://news.discovery.com/space/earth-like-planet-life.html

[ ]´s

[Darvince]

There have been at least 10 of these so far. >_>

Wait G! Woo! More than Cancri! Take THAT, Cancri.

[atomic7732]

Wtf, I have been far behind on extrasolar planets. How the heck do we all of a sudden have two systems with more than 55 Cancri???

Edit: Odd... I look back to how far it's been since I last checked... and there was no 851 f or g... I do remember e being discovered though.

Edit2: Oh it was discovered today! lol exoplanet.eu still doesn't have it.

[APODman]

As soon as the orbital elements was published lets go insert the planets in US !

[Naru523]

Epic. Hopefully it is because I would love to see a map of another planet 

[Bla]

Awesome. More information is available on it's Wikipedia page.
Looks like the orbit isn't very eccentric (which would had made it very hard for it to have life anyways), but it crosses the orbit of Gilese 581 d according to the 2d graphic. :/
It's SM axis is 0,146 AU.

[APODman]

Finally released the article with the details of the discovery.

I used the data to put the planet in the U.S. but still it is beyond the habitable zone of the star, which I have done wrong?

The paper of discovery can be read here:
- http://fr.arxiv.org/PS_cache/arxiv/pdf/1009/1009.5733v1.pdf

More here: http://exoplanet.eu/star.php?st=Gl+581

[atomic7732]

US's calculations of habitable zone may be different.

[Dan Dixon]

I used the data to put the planet in the U.S. but still it is beyond the habitable zone of the star, which I have done wrong?

You've done nothing wrong. That was my result as well.

The US Habitable zone calc is based on the luminosity of the star and apparently my range and their range are different. Let me know if you see anything about the habitable zone range that they used.

[Dan Dixon]

Turns out the formula I'm using to calculate the habitable zone is wrong at more extreme ranges. I think I'll be able to fix this in (maybe) the next release.

[Darvince]

I wonder if the planet can sustain ice at its poles...

[atomic7732]

Idk. Let's make a detector with a mass of near 0, so it can go near the speed of light, and make it Gliese 581 g in about 20 years!

[Naru523]

A radiowave was sent into the system in 2000 I think.
Should reach in 2020.

[atomic7732]

A radiowave was sent into the system in 2000 I think.
Should reach in 2020.

One was sent to 55 Cancri too.

A Message From Earth (AMFE) is a high-powered digital radio signal that was sent on 9 October 2008 towards Gliese 581 c, a large terrestrial extrasolar planet orbiting the red dwarf star Gliese 581. The signal is a digital time capsule containing 501 messages that were selected through a competition on the social networking site, Bebo. The message was sent using the RT-70 radar telescope of Ukraine's National Space Agency. The signal will reach Gliese 581 in early 2029.

Sucks don't it? Send one to g...

I suspect there may be planet h between c and g... and j outside of f. I suspect the won't use i, cause asteroids dont. No clue why.

[Darvince]

What? No Gliese 581 i? Why not? Asterpids don't?

[atomic7732]

Yeah... Asteroids go 2010 AG, AH, AJ or, HX, HY, HZ, JA, JB, JC

[Naru523]

Gliese 581 f passes Venus' orbit.


Not to mention that G518's planets almost dominates for Most earth-like exoplanets... haha.

[atomic7732]

Link to Most earthlike thing?

[Bla]

Link to Most earthlike thing?

Link.

[Dan Dixon]

I think I'll be able to fix this in (maybe) the next release.

Barring a quick reply on an email I just sent, this fix won't be in the next release. I don't yet have a good formula to calculate this. I definitely want to fix this however. Formula anyone?

[atomic7732]

ask http://exoplanet.eu They have an app with a habitable zone on it.

[Dan Dixon]

I can't find a habitable zone app on exoplanet.eu.

Can you post the link to what you're talking about? I'd love to see this.

[Laura]

If the habitable zone is defined simply as the distance from a star where the effective temperature is in the range 0° to 100°C then it is straightforward to calculate the radii of the zone's inner and outer bounds. The relevant formula is:
L = 4πr²σT⁴

where L is the star's luminosity, r is the distance from the center of the star, σ is the Stefan-Boltzmann constant (=5.67 × 10^-8W × m^-2 × K^-1), and T is the effective temperature (in kelvin). For the Sun, this yields a range for the habitable zone of 0.7 to 1.5 AU. The zone range for other stars can then be calculated easily since, from the above formula:
L(star)/L(sun) = r(star)²/r(sun)²

In the case of Vega, L(star)/L(sun) = 53, which gives a range for the zone of 5.1 to 10.9 AU. In the case of Kapteyn's Star, L(star)/L(sun) = 0.004 and the corresponding range is 0.044 to 0.095 AU.

[Dan Dixon]

Thanks Laura.

I'm over thinking this problem and turns out I had the math wrong.

The basic formula seems to be to take the Square Root of the Luminosity (where our Sun = 1) of the star and multiply it by .7 and 1.5 to get the inner and outer ranges. Another range seems to be 0.82 and 1.2. Any thoughts on which one I should use?

Using 1.2 the outer edge of the habitable zone is just shy of catching the orbit of Gliese 581 g.

[atomic7732]

I was saying that there is an app for iPod and iPhone that has habitable zones in it. It says they calculate it based on certain things.

[Laura]

Thanks Laura.

I'm over thinking this problem and turns out I had the math wrong.

The basic formula seems to be to take the Square Root of the Luminosity (where our Sun = 1) of the star and multiply it by .7 and 1.5 to get the inner and outer ranges. Another range seems to be 0.82 and 1.2. Any thoughts on which one I should use?

Using 1.2 the outer edge of the habitable zone is just shy of catching the orbit of Gliese 581 g.

How did you arrive at the 0.82 and 1.2 results?

[Dan Dixon]

Good question. It's a value that I've seen.

This document says 0.8 - 1.2.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.140.8948&rep=rep1&type=pdf
Search for "range" to find it.

This also has those values (0.82 - 1.2):
http://www.bumply.com/astro.html

document.formSums.txtInnerHab2.value =(0.82*Math.sqrt(parseFloat(lum)));
document.formSums.txtOuterHab2.value =(1.2*Math.sqrt(parseFloat(lum)));

[Laura]

Good question. It's a value that I've seen.

This document says 0.8 - 1.2.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.140.8948&rep=rep1&type=pdf
Search for "range" to find it.

This also has those values (0.82 - 1.2):
http://www.bumply.com/astro.html

document.formSums.txtInnerHab2.value =(0.82*Math.sqrt(parseFloat(lum)));
document.formSums.txtOuterHab2.value =(1.2*Math.sqrt(parseFloat(lum)));

Well, the first document you cited, when I search it for range, does indeed find 0.8 and 1.2 but those values are not about habitable zone ranges in that context. They refer to solar masses.

The second link does use a formula for calculating habitable zones, in accordance with the 2300AD role-playing game rules.

In any event, habitable zones are tricky. They depend not only on the star, but also on the planet in question. I.e. the planet might have more or less greenhouse gases. Technically, if we could pump enough such gases into the atmosphere of Mars, it could be made habitable, yet it is outside the habitable zone (albeit not by a very wide margin).
At the end of the day, one has to make a rather arbitrary decision: What temperature range represents a habitable zone? The quote I posted earlier decides it is a 0 to 100 degrees celsius range (presumably because that is the range in which liquid water is possible). It entirely ignores the greenhouse effects of water vapour and other gases on planets in that range.
Apparently, the 2300AD rulebook thinks the margin should be narrower, and it might well be correct, at least when dealing with very Earth-similar conditions of life.

How about making the zone according to the liquid water range, but represented visually as a gradient; densest in the middle and thinning out towards either extreme?

EDIT: The first article seems to arrive at a habitable zone of about 0.8 to 1.7 AU. It doesn't provide the numbers directly, so I'm estimating them from the diagram (figure 2).

[atomic7732]

No worries, fix it later, f and g's discoveries are currently retracted.

Back to Cancri in 2nd. 

[Naru523]

But it's still fun to do with the planets, since there information are still here.