Astroblog: Not Kevin Costner's Water World (in Celestia)

Thursday, February 23, 2012

Not Kevin Costner's Water World (in Celestia)

GJ 1214b visualised in Celestia.

I'm still continually amazed about what we find out about extrasolar planets, I know I shouldn't be, but I am.

Just finding these worlds is amazing enough, but for a couple of these worlds we know what's in their atmospheres. For a Neptune sized world 40 light years from us, GJ 1214b, it looks like it's a water world.

Weeellll sort a water world, according to a recently released paper, it's a hellish steam bath world, with perhaps 50% of it's atmosphere water vapour at a temperature of 230° Celsius (but see this paper as well, which is more suggestive of haze). The rest of the atmosphere is more likely hydrogen and helium. Of course, more onservation is needed, but it's amazing to think we can glimpse what this world is like from fleeting dips in a stars light.

Hubble press release here, and thoughtful commentary by the Bad Astronome r . Once again I've made Celestia files for the system. One for the star (which isn't in the default files) and one for the planet.

As usual, copy the data here to plain text files (GJ1214.stc and GJ1214b.ssc), copy both of the files to the Celestia extras folder. The star is around 950 lightyears away in Lyra, so in the Celestia star browser, you will have to show around 500 stars to see Kepler-20 in the list.
I'll have to update my Celestia Exoplanet Tour as well.

===============GJ1214.stc======================================
#Mearth Project

"GJ 1214"
{
RA 258.8292
Dec 4.9639
Distance 40 # light years from published data
SpectralType "M4.5"
AppMag 14.67
}
=======================================================
==================GJ1214b.ssc============================
"b" "GJ 1214"

# Neptune like world
# All data from original papers or URL

{
Texture "exo-class4.*"
NightTexture "exo-class4night.*"

Mass 6.55 # M.sin(i) = 6.55 Earth
Radius 17080.284 # 2.678 Earth radi, from URL

#InfoURL "http://en.wikipedia.org/wiki/GJ_1214_b"
#InfoURL "http://exoplanet.eu/star.php?st=GJ+1214"

EllipticalOrbit {
Period 0.004326842
SemiMajorAxis 0.014
Eccentricity 0.27
ArgOfPericenter 267 #guess
Inclination 88.8
#MeanAnomaly 271
}

# likely to be in captured synchronous rotation
}

AltSurface "limit of knowledge" "GJ 1214/b"
{
Texture "extrasolar-lok.*"

}

==============================================================

Labels: celestia, exoplanet, extrasolar planet