# Talk:HD 40307 g

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## German article info

This German article contains key information and quotes further sources (which probably contain that info in English): http://www.spiegel.de/wissenschaft/weltall/exoplanet-hd-40307-g-super-erde-koennte-lebensfreundlich-sein-a-866023.html

## High Eccentricity means not habitable

The data page in the extra solar planet catalogue lists the Eccentricity of this planet is anywhere from 0 to 0.58 (0.29 +/- 0.29),
and anything above the median would mean a temperature swing from Venus-like to Mars-like for the 6.5 month period.
This isn't habitable at all, not just for the extreme temperatures, but the extremely harsh weather would scour the planet clear of any life
on the surface, that was not perhaps aquatic, protected from the weather effects.
Let's stick with the mathematical facts and not hipe false ideas.
24.79.38.15 (talk) 23:35, 8 November 2012 (UTC)

Your arguments are correct, if the planet indeed has a high eccentricity. However, anything between 0.0 and 0.58 is probable atm. So, unless there is a detailed study examining the habitibility, I think the current style of the article is just right, as it describes the admittedly vague guesses of experts on the subject. Ruling it out by doing math on Wikipedia would be original research, I suppose. -- Aepsil0n (talk) 16:48, 13 January 2013 (UTC)

yeah, no since original research is for what doesn't belong in an article, discountng something with simple math is common sense. 24.79.38.15 (talk) 09:49, 1 May 2013 (UTC)

### Math

For users interested in the irradiance (Watts/ meter squared) comparisons.
Rs=0.72, Ts=4977, Dp=0.600, e=0.29
=(((0.72*695500000)^2)*(0.0000000567051)*(4977^4))/((0.6-(0.6*0.29))*149597870690)^2
DISTANCE, ..........Watts/m^2, ......Earth=100%
Perihelion, ............2124.43,........155.51%
Semi-Major Axis,... 1070.93,......78.39%
Aphelion, ...............643.55,.........47.11%

Rs=0.72, Ts=4977, Dp=0.600, e=0.6 .[1]
=(((0.72*695500000)^2)*(0.0000000567051)*(4977^4))/((0.6-(0.6*0.29))*149597870690)^2
DISTANCE, ..........Watts/m^2, ......Earth=100%
Perihelion, ............6693.29,........489.96%
Semi-Major Axis,... 1070.93,......78.39%
Aphelion, ...............418.33,.........30.62%

Sun & Earth's irradiance variance for comparison.
Rs=1.0, Ts=5778, Dp=1.0, e=0.01671123
=(((1.00*695500000)^2)*(0.0000000567051)*(5778^4))/((1.0-(1.0*0.01671123))*149597870690)^2
DISTANCE, ..........Watts/m^2, ......Earth=100%
Perihelion, ............1412.91,........103.43%
Semi-Major Axis,... 1366.08,...... 100%
Aphelion, ...............1321.54,........96.74%
24.79.38.15 (talk) 15:06, 6 January 2013 (UTC)

## The Mikko Tuomi citation

From Article: 'Lead author Mikko Tuomi, also of the University of Hertfordshire, stated "If I had to guess, I would say 50-50, But the truth at the moment is that we simply do not know whether the planet is a large Earth or a small, warm Neptune without a solid surface."[7]'

I'm not THE expert on the so called Ice giants (Uranus & Neptune). But I would think that the 'cores' of Neptune & Uranus are made of ices (from water, ammonia, methane) and rock. So if the destinction between the gas giants (Saturn & Jupiter) and the Ice giants is that a large amount of the gasses are in a frozen icy state and that there's a solid core:

How can Tuomi's assumption be explained, that HD40307g is a 'warm Neptune without a solid surface' ? If it's warm (habitable zone!) than it's not an icy neptunian world. If it doesn't have a solid surface it's just another gas planet.

Just irritated...92.230.80.255 (talk) 12:01, 21 February 2013 (UTC)

1. ^ "Trio of 'super-Earths' discovered". BBC news. 2008-06-16. Retrieved 2008-06-16. |coauthors= requires |author= (help)