Jackie's Hab-Zone Calculator

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Jackie Silver

Jackie Silver
I'm working on a program that calculates the habitable zones for stars.

It isn't finished (I need more data on some of the rarer types of planet) but it's in a good enough state that I can make it available without shame. :)

Version 0.25 (new, multiple-star systems) (Compiled Windows 64bit .exe and source.)

I've added a slightly modified version which works on Linux - install easygui for Python 3, pillow for Python 3 and then run the source from IDLE.
Keep the font file in the same folder as the source code.

Version 0.26 (Linux source only.)

Version 0.17 (older, gfx)

Version 0.14 (older, no gfx) (Windows executable.)
The Python script original is included in the archive if you're curious; if you want to compile it yourself it relies on easygui so you'll need that.

Extract the archive and run JSHZC17.exe;

jshzc13pic1.png

Enter the parameters of the star you're looking at - its radius and temperature. (Defaults are for Sol.)

jshzc13pic2.png

If you're curious about finding the expected temperature of a planet at a particular distance, enter that distance into one of the boxes here, otherwise accept the defaults.

jshzc13pic3.png

You'll get an information list which shows you where the main habitable zone is (inside which you will find terraforming candidates and earthlike worlds); it also shows rough boundaries for where you can find non-terraformable water worlds, ammonia worlds and metal-rich worlds (I need more data to narrow down these zones, but they're broadly accurate.) The values for gas giants represent the closest a gas giant of that class can be, although again I'm not 100% certain they should be fairly close; it's not particularly useful information in any case. At the bottom, the values given show the blackbody, general (albedo 0.35, most planet types) and iceball (albedo 0.6, ice and rocky ice worlds) temperatures for given distances. If you find an ordinary planet without an atmosphere, it should have the "general" temperature, or if you find an iceball the "iceball" temperature. Gas giants are higher because they contribute heat of their own, and planets with an atmosphere will also be hotter, especially if the atmosphere is CO2.

The calculations are only accurate for single-star systems, although you may get decent results on multiple stars if they are a long way apart or if the primary is much brighter than the other stars.

There are some (very rare) handcoded systems (generally of type plain V) where the star's luminosity as evinced by the temperatures of planets does not match the parameters given in the system view. It's a funny old galaxy. ;)

All feedback appreciated, happy scanning!

Updated link to v. 0.14; no major changes, narrowed down the bands for Ammonia and Metal-Rich Worlds a little.

Updated link to v. 0.15; added a logarithmic graphical display for the major zone boundaries, other minor tweaks.

Updated link to v. 0.16; entering a value of 0 for star radius will default to using the radius of a Neutron star, other minor tweaks including changed output to png.

Updated link to v. 0.17; modified the graphical display, added indicator for Class II Gas Giants ("the valuable ones, innit"), other minor tweaks.

Updated link to v. 0.25; added support for multiple-star systems, added indicator for Class I Gas Giants, greatly improved ranges for WW and AMW, added support for WD, other tweaks.

ssdout.png
 
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Jackie Silver

Jackie Silver
I've uploaded a new build - I got some better data on the ranges for Ammonia worlds and Metal-rich Worlds.

I've included my data spreadsheet in the archive - it's quite interesting to try parameters from different stars and see where the hab zone falls.

Here's an H-R diagram based on that spreadsheet - while the sequence here looks very "tight" there's still some big variations in luminosity between stars of similar spectral classes and within the classes.
(I didn't normalise the luminosity on the y-axis to L/Lsol, it just needs dividing by 5778 but for some reason Excel loses the axis every time I try and I couldn't be bothered to work out how to stop it. :D )

HRplot.png
 

Reido

Reido
Hi Jackie,

I was following your work in Nutter's thread and really appreciate it.

When you say: "it also shows rough boundaries for where you can find non-terraformable water worlds, ammonia worlds and metal-rich worlds (I need more data to narrow down these zones, but they're broadly accurate.)"

Are you referring to the metal-rich planets? I'm on a long term exploration mission now and came across 4 or 5 of those in the last couple of days (two around one star), I could probably find them again (log books are handy for that) and post a screenshot of the system maps (highlighting the main/secondary stars and MR planets respectively) if that would help.

Andrew
 

Jackie Silver

Jackie Silver
Hi Andrew - yes, the metal-rich worlds that are close in to the star are one of the things I'm hoping to pin down further.

What makes things complicated is that whether a close-in planet is "High Metal Content" or "Metal Rich" depends on both its distance (hence temperature) and (so far as I can tell) its mass - small planets are more likely to be MRW and large ones more likely to be HMC. The boundary where MRWs stop is around 1000K. It's further complicated because the temperature gradient near a star is very high, but the distance readouts from the system map (in AU) are rounded so for an accurate reading of a planet's temperature when it's only say 0.02 au from the star you need to physically fly along right next to the planet's orbital track and check the distance to the star. In any case, except for the most luminous stars the metal-rich planets are always very close to the star and can be identified by their distinctive appearance on the "blue-ball" scanner.

With the ordinary main habitable zone, there's a clear zone between blackbody 314K and 224K - any HMC planet (of an appropriate size) within that boundary will be terraformable, and any HMC planet outside it will not, so it's possible to define it very exactly. The same can't be said for Ammonia worlds - I have certain temperatures for the highest and lowest blackbody temperatures of AMWs that I've seen, but no way to tell whether those represent the real boundary of the zone or whether much hotter and colder ones are possible - so it's a case of waiting to find new ones and checking to see if they extend the boundaries of the zone. And unfortunately they're rare, and I need ones that are orbiting a single star which cuts it down further. :)

I'm not sure exactly how Water Worlds are distributed - all Water World terraforming candidates lie within the main zone, but not all Water Worlds in the main zone are terraformable, and I'm not sure whether Water Worlds can be found right up to the 314K end of the main zone or whether they start appearing somewhere in the middle. Just need more data, I'll get there. :)
 

Reido

Reido
Coincidentally, the CBC Radio show Quirks & Quarks just had a segment on the formation of planets like Mercury (which is classed as a metal-rich planet in the game).

The gist of it is that in the early solar system there may have been as many as 4 small planets orbiting inside the orbit of where Mercury is now and that due to the inherent instability of most planetary orbits they eventually collided with the result being that the lighter elements were thrown off due to the high velocities and the dust getting blown away by the solar winds leaving the heavier elements behind to form Mercury. This theory would also explain Mercury's orbital eccentricities.

Here's a link to the podcast of that segment:

http://podcast.cbc.ca/mp3/podcasts/quirks_20150314_30725.mp3

Just finished breakfast here so it'll be a couple of hours before I fire up the big computer, but I'll post some more data points for you (about 6 I think) and keep an eye out for any more as I'm expecting to stay out until patch 1.3 comes out. Right now I'm plotting economical routes from one type G star to the next with a few other star types thrown in between so I should be seeing a good representative sample of most common systems types.

I'm not actually headed anywhere in particular, although I'm going in the general direction of the Elephant's Trunk Nebula to keep me from going in circles. I'm more or less just "filling in the blanks" of plain old cartographic work so it'll be nice to send the occasional preliminary report "back home" to the Stellar Cartographic Research Facility :D

Andrew

EDIT: Added info

I've got the system map screenshots ready for 6 metal-rich planets (1 image of main/secondary stars and 1 image per planet, one system has two side by side). Where would you like me to post them? I don't want to clog up your thread regarding the software program you've made available.
 
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Jackie Silver

Jackie Silver
Mmm, you could stick them up on Imgur and PM me the link if that works for you? Interesting to see if you've got any that are out of the usual bounds. There's some kind of capture mechanism in the model which can lead to High Metal Content planets being left in far-out orbits, I don't think there's anything in principle to stop a Metal-Rich planet ending up the same way but I've never seen one.
 

Jackie Silver

Jackie Silver
I've uploaded a new version of the calculator which adds a basic graphical display for the major zone boundaries.
It uses a logarithmic scale going from 0.01 to 100 aus.
Grey is for Metal-Rich Worlds, Green for the main habitable zone, Blue for Water Worlds, Red-brown for Ammonia Worlds.
The background dark yellow represents High Metal Content planets which can be found everywhere, and the background white loosely represents iceballs and riceballs.
(The present dividing line is set at about 150K and is very imprecise - that's one of the areas for improvement.)

Here are example outputs for stars with the Sun's temperature and 1, 2 and 3 solar radius: you can see how the hab-zones shift outwards and expand with the increasing luminosity.

ssdout5778-1.png

ssdout5778-2.png

ssdout5778-3.png

The image is displayed after you enter star parameters and a copy is saved to the program folder.
(They're bitmaps, I'll change the output to .png next time as they're 300k each which is a pain.)
 

_Dastardly_

D
Neutron stars (radius 0) break it :( (Or I'm doing something wrong...)

Main Habitable Zone (WW/CFT, HMC/CFT, Rocky/CFT, ELW)
------------------------------
Lower Bound: 0.0 au (about 0 ls.)
Upper Bound: 0.0 au (about 0 ls.)
 

Jackie Silver

Jackie Silver
_Dastardly_ said:
Neutron stars (radius 0) break it :( (Or I'm doing something wrong...)
Click to expand...

No, that's a good point - I hadn't anticipated using it on Neutron stars. I've uploaded a new build which assumes that a value of 0 for radius implies a Neutron star.

Obviously I haven't yet checked this against Neutron stars in the game. :D
 
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Jackie Silver

Jackie Silver
New look, cleaned-up, totally innocent zone display graphics.

ssdout.png

Next stage is to add lines at the distance points specified by the user, and lines for the gas giant closest points.

I've changed the close-in boundary for water worlds to represent the highest temperature I've observed; I'm still not sure whether they can go right up to the boundary.

I'll build and upload it some time tomorrow.

Here's a ludicrously hot iceball (846K blackbody temperature) in the meantime, just to confound all expectations of where to find them. :)

BhaSQqx.jpg
 

Jackie Silver

Jackie Silver
Andargor said:
Now to find a way to overlay this on the System map...
Click to expand...

Yes, I'd like to do something like that - I managed something similar with a map mod for the nifty Sir, You Are Being Hunted but only by good fortune. I'm no great shakes as a programmer, if that's not already apparent... :D

I've uploaded version 0.17, which changes the display output and adds an indicator for the range where Class II Gas Giants can be found. (The code is in to add lines for the various user-specified points and for the other gas giant ranges, but it's too cluttered.) Also changed the ranges slightly to reflect better data.

ssdout.png
 

Jackie Silver

Jackie Silver
I'm working on expanding this to cover systems with multiple stars. Progress is slow, but the current version is able to handle the basics.
I'm checking it against the game now and expect to be disappointed. ;)
 

J. diGriz

J
what info do you need on neutron stars, I'm 25,000 LY out and have been scanning neutrons for the quick credits. Off the cuff I can tell you that there are terraform worlds at approx ~1200Ls-~1800Ls from the neutron star. As I have found a few when they look earth-like.
 
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