Guide / Tutorial Nutter’s explorers guide to the Galaxy

Werppa

Werppa
Jackie Silver said:
That's on the small side, but still reasonable, I think. Stars which begin life as "M" and "K" will still be on the Main Sequence as they're very long lived (and may never become red giants anyway if they're very small); a 0.4 solar mass red giant would have to be a larger star (probably "G" or "F" type) that had lost a considerable fraction of its mass somehow over time. There's various ways that happens.

The basic gist for giants is that an ordinary star is fusing hydrogen to helium in its core - when the hydrogen is running low you end up with a core of degenerate (it's only stopped from collapsing by quantum mechanical effects) helium that's too cold to fuse (it's extremely hot but not stupendously hot) and the hydrogen that's left starts fusing in a big shell around the core; the effect is that the star bloats up into a giant because more energy is being produced (pushing the outer layers further "up") but its surface temperature cools somewhat (because there's a lot more surface area) so the star gets bigger and appears cooler (i.e. shifts "down" the scale from e.g. "K" to "M.") At some point it may start fusing helium and other things, and supergiants are another thing entirely, but this has become complicated enough... :)
Click to expand...

Thanks for taking the time to reply! And they say that you don't learn anything from video games :)
 

Jackie Silver

Jackie Silver
Ambivalent said:
Regarding habitable zones, from my observations, particularly around neutron stars and red super giants I feel like star type, brightness, slar mass even can be discarded as factors in determining where it will lie. I believe its just a function of the stars temperature and surface area with which it can radiate that heat which determines where the CTF's will be.

So I think we could discard star type from the equation (though it is a very useful guide) and just makes a chart of temperature vs solar radius to see where the sweet spot will be.
Click to expand...

Yeah, seems like. I'm going to work backwards using this Python program and try to determine exactly how the game is going about things.
(bodged together from this relevant Wiki page)

Code: 
# Snowliner 2

Tsun = 5778 # Kelvin
Rsun = 6.96e8 # Metres
au = 1.496e11 # Metres
albedo = 0 # For a perfect black body

def snowliner(T,R,distance,albedo):
    distance *= au
    calc = (R / (2 * distance)) ** 0.5
    tempI = T * calc
    albedofactor = (1 - albedo) ** 0.25
    tempF = albedofactor * tempI 
    return int(tempF)

def dfort(T,R,albedo,Tdes):
    div = (Tsun / Tdes)
    divs = div ** 2
    distance = (R * divs) / 2
    distance /= au
    return round(distance,2)

for distance in range(1,21):
    print(snowliner(Tsun,Rsun,distance*.1,albedo))

The snowliner function returns the temperature at a given distance in au.

The dfort function will return the distance in au for a given temperature, e.g.:

dfort(Tsun,Rsun,0,300)

Returns 0.86 (au), which is to say that a black body at 0.86 au from the Sun should have a temperature of 300 Kelvin.
I need to mess on with this (pretty sure I've made a mistake somewhere, do say!) but it should get some in-game results when I find convenient test systems. :)
 
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Jackie Silver

Jackie Silver
Muhahahaha.

Code: 
# Snowliner 3

Tsun = 5778 # Kelvin
Rsun = 6.96e8 # Metres
au = 1.496e11 # Metres
albedo = 0 # For a perfect black body

def snowliner(T,R,distance,albedo):
    R *= Rsun
    distance *= au
    calc = (R / (2 * distance)) ** 0.5
    tempI = T * calc
    albedofactor = (1 - albedo) ** 0.25
    tempF = albedofactor * tempI 
    return int(tempF)

def dfort(T,R,albedo,Tdes):
    R *= Rsun
    div = (Tsun / Tdes)
    divs = div ** 2
    distance = (R * divs) / 2
    distance /= au
    return round(distance,2)

##for distance in range(1,21):
##    print(snowliner(Tsun,1,distance*.1,albedo))

##print(snowliner(2966,0.5441,0.03,0.25))
##print(snowliner(2966,0.5441,0.05,0.25))
##
##print(snowliner(5568,0.9921,0.07,0.3))

talb = 0.6
##print(snowliner(2369,0.4281,0.6,talb))
##print(snowliner(2369,0.4281,0.84,talb))
print(snowliner(2369,0.4281,1.07,talb))
print(snowliner(2369,0.4281,1.48,talb))
print(snowliner(2369,0.4281,1.96,talb))
print(snowliner(2369,0.4281,2.67,talb))
print(snowliner(2369,0.4281,3.45,talb))
print(snowliner(2369,0.4281,4.91,talb))

Preliminary results: tested against a singleton "M" dwarf surrounded by a bunch of atmosphere-less iceballs.
Rstar = 0.4281 solar radii. Tstar = 2369 Kelvin.
After a bit of trial and error, using an albedo of 0.6 for the iceballs.
Results agree to within rounding error. :)

distancepredictedactual
1.075757
1.484849
1.964242
2.673636
3.453232
4.912627

This is a gateway to all manner of !!SCIENCE!! - should be able to extend it to other planets (using atmosphere-less moons for those planet types which always have atmosphere), then determine the heating effects of different atmosphere compositions, and especially gas giants. Hab zones follow.
 
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mossfoot

mossfoot
Jackie Silver said:
Muhahahaha.

Code: 
# Snowliner 3

Tsun = 5778 # Kelvin
Rsun = 6.96e8 # Metres
au = 1.496e11 # Metres
albedo = 0 # For a perfect black body

def snowliner(T,R,distance,albedo):
    R *= Rsun
    distance *= au
    calc = (R / (2 * distance)) ** 0.5
    tempI = T * calc
    albedofactor = (1 - albedo) ** 0.25
    tempF = albedofactor * tempI 
    return int(tempF)

def dfort(T,R,albedo,Tdes):
    R *= Rsun
    div = (Tsun / Tdes)
    divs = div ** 2
    distance = (R * divs) / 2
    distance /= au
    return round(distance,2)

##for distance in range(1,21):
##    print(snowliner(Tsun,1,distance*.1,albedo))

##print(snowliner(2966,0.5441,0.03,0.25))
##print(snowliner(2966,0.5441,0.05,0.25))
##
##print(snowliner(5568,0.9921,0.07,0.3))

talb = 0.6
##print(snowliner(2369,0.4281,0.6,talb))
##print(snowliner(2369,0.4281,0.84,talb))
print(snowliner(2369,0.4281,1.07,talb))
print(snowliner(2369,0.4281,1.48,talb))
print(snowliner(2369,0.4281,1.96,talb))
print(snowliner(2369,0.4281,2.67,talb))
print(snowliner(2369,0.4281,3.45,talb))
print(snowliner(2369,0.4281,4.91,talb))

Preliminary results: tested against a singleton "M" dwarf surrounded by a bunch of atmosphere-less iceballs.
Rstar = 0.4281 solar radii. Tstar = 2369 Kelvin.
After a bit of trial and error, using an albedo of 0.6 for the iceballs.
Results agree to within rounding error. :)

distancepredictedactual
1.075757
1.484849
1.964242
2.673636
3.453232
4.912627

This is a gateway to all manner of !!SCIENCE!! - should be able to extend it to other planets (using atmosphere-less moons for those planet types which always have atmosphere), then determine the heating effects of different atmosphere compositions, and especially gas giants. Hab zones follow.
Click to expand...

Dude, I love the fact you're getting into this in this fashion :) Can't wait for the results to be broken down and conclusions made.

So we're going to have people conducting scientific observations of a simulation of a world, based on scientific observations in the real world... how meta! I should drop some different sized canonballs and a feather on board a rotating space station's hanger to double check the 0.1g effect ;)
 

Ambivalent

A
Jackie Silver said:
Muhahahaha.

Code: 
# Snowliner 3

Tsun = 5778 # Kelvin
Rsun = 6.96e8 # Metres
au = 1.496e11 # Metres
albedo = 0 # For a perfect black body

def snowliner(T,R,distance,albedo):
    R *= Rsun
    distance *= au
    calc = (R / (2 * distance)) ** 0.5
    tempI = T * calc
    albedofactor = (1 - albedo) ** 0.25
    tempF = albedofactor * tempI 
    return int(tempF)

def dfort(T,R,albedo,Tdes):
    R *= Rsun
    div = (Tsun / Tdes)
    divs = div ** 2
    distance = (R * divs) / 2
    distance /= au
    return round(distance,2)

##for distance in range(1,21):
##    print(snowliner(Tsun,1,distance*.1,albedo))

##print(snowliner(2966,0.5441,0.03,0.25))
##print(snowliner(2966,0.5441,0.05,0.25))
##
##print(snowliner(5568,0.9921,0.07,0.3))

talb = 0.6
##print(snowliner(2369,0.4281,0.6,talb))
##print(snowliner(2369,0.4281,0.84,talb))
print(snowliner(2369,0.4281,1.07,talb))
print(snowliner(2369,0.4281,1.48,talb))
print(snowliner(2369,0.4281,1.96,talb))
print(snowliner(2369,0.4281,2.67,talb))
print(snowliner(2369,0.4281,3.45,talb))
print(snowliner(2369,0.4281,4.91,talb))

Preliminary results: tested against a singleton "M" dwarf surrounded by a bunch of atmosphere-less iceballs.
Rstar = 0.4281 solar radii. Tstar = 2369 Kelvin.
After a bit of trial and error, using an albedo of 0.6 for the iceballs.
Results agree to within rounding error. :)

distancepredictedactual
1.075757
1.484849
1.964242
2.673636
3.453232
4.912627

This is a gateway to all manner of !!SCIENCE!! - should be able to extend it to other planets (using atmosphere-less moons for those planet types which always have atmosphere), then determine the heating effects of different atmosphere compositions, and especially gas giants. Hab zones follow.
Click to expand...


Repped! Also, selling data still takes a reallllly long time but its cool to be able to see all the info! First time i've been in dock since before 1.1 and its all rather different, but in a good way.
 

Jackie Silver

Jackie Silver
After some more observations, it looks like the albedo for Rocky/Ice worlds is also 0.6, and the albedo for High Metal Content worlds is 0.35.

Working hypothesis is that the albedos for Rocky, Metal-Rich, Water-World and Earth-likes are also 0.35, and that all worlds of a particular type have the same albedo.
Another hypothesis is that a world being a terraforming candidate has no effect on the albedo.

Working out the effects of the atmospheres is proving difficult but I should get there with a lot more data.

By looking at the black body equivalent temperatures for a particular distance, and assuming that the albedo of all similar types of worlds are similar, it should be possible to given a "black body equivalent" hab zone range.
E.g. I found a Water World / CFT at a black body equivalent temperature of 251 Kelvin, while its actual temperature was higher due to its atmosphere and would be lower due to albedo, it should be possible to build the hab zones based purely on the black body temperatures because as far as I can tell the game does it without reference to the atmosphere. Same for other world types.

One thing I'm wondering is whether the frost line is calculated in game based on the luminosity of the star during planet formation (which will be lower) - that would be the accurate way to do it - or the luminosity of the star as it presently is. Hopefully can find that out soon.
 

Jackie Silver

Jackie Silver
I confirm that Metal-rich Worlds and Rocky worlds are definitely also albedo 0.35

Class I, Class II, Class III, Class IV Gas Giants and Gas Giants with Water- or Ammonia-based Life are albedo 0.35; probably all gas giants but I need to check more.

The temperature of a gas giant is made of two components:

Firstly its "natural" temperature, call it Tnat, based on its position from the star, the star's temperature and radius and the gas giant's albedo.
Tnat = ((1-albedo)**.25) * Tstar * ((Rstar / 2*distance)**.5)
(Think I've written that out right. It works in the program at any rate. This is the same as for other planets.) ;)

Secondly its "increase" temperature, call it Tinc, based on its mass.
Tinc ~ 0.02 * (Mass ** 1.3)
(The coefficient and power here may not be exactly right, but they're certainly close.)

Final temperature = Tnat + Tinc
Works to within a few degrees on the ones I've looked at so far. :D

(edited to add)

Following from this we can derive theoretical maximum masses for the gas giants. (like the way I switch into pompous didactic mode? :) )
If a gas giant is sufficiently far from its star that almost all the heat is coming from itself, then at some mass it will be too hot to be a Class I, again at some higher mass it will be too hot for Class II, and so on.
Tnat = 0; T = Tinc only
So maximum mass = (boundary temperature / .02)**0.7692

The boundaries between the gas giant types are implemented, I think, as:
Class I - 0 to 150K
Class II - 150K to 250K
Class III - 250K to 800K
Class IV - 800K to 1400K
Class V - over 1400K

Which gives us:
Class I - maximum 956 Earth masses
Class II - maximum 1416 Earth masses
Class III - maximum 3467 Earth masses
Class IV - maximum 5331 Earth masses (which is over the approximately 13 Jupiter mass (4121 Earth mass) traditional limit at which a gas giant becomes a brown dwarf)
Class V - unbounded

From the Universal Cartographics book of records, the highest reported values at present are:
Class I - 769 Earth masses (80% of max)
Class II - 1085 Earth masses (76% of max)
Class III - 3230 Earth masses (93% of max)

Current version of the program.
 
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Nutter

Nutter
Awesome Stuff Jackie - do you have a SS you could share?

Also in other news - 1.2 fixes the confused metal rich descriptions - Metal rich is now Metal rich :D
 

Jackie Silver

Jackie Silver
Nutter, this is the spreadsheet I'm working with at the moment. It's in two main parts.
Firsty I'm trying to narrow down the boundaries within which certain types of planet appear. The temperatures given are the absolute calculated blackbody temperatures (so what they would have if they were albedo 0 and had no atmosphere) so they don't represent the temperature you'd see on a planet. They're the "underlying" temperature for a lump of coal floating around in the same orbit. :)

Secondly I'm trying to get the boundaries between different spectral types for "G" stars - GVAB, GVA, GVB 0-9 - to see what the maximum and minimum radius and temperature are for each subclass.
When I get this I can work out what an average star of that precise subclass looks like and then use it to generate a graph showing the absolute calculated blackbody temperatures around it.

For example, here's one for our own Sun: (distance in aus on the x axis, temperature in K on the y)

sun bb curve hab.jpg

I think the habitable zone for terraforming candidates of all types lies broadly between blackbody 215 K and 315 K (ish) which I've marked on the diagram.
(I could just get the exact distances by saying "computer, what distance has temperature 215K, what distance has 315K" so that can be marked up properly.
It will be interesting to see how broad the different spectral subclasses are - what the most difference is between the habitable zones of one G4VAB and another G4VAB say.
Hopefully not very much, or we'll end up with dozens and dozens and dozens of graphs. :D )

I need more data to narrow down the ranges for particular things like earth-likes.

(As ever it all goes out the window when there's more than star around, and even gas giants can be a significant source of heat to their orbiting moons. But we're good for single stars.
Except that the more massive stars usually have a bunch of companion brown dwarfs, t-tauris and other big bright hot things with them.)
 
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Heater

Heater
All,

General question about the route planner and fuel scooping...
Does the route planner take the max jump range and scooping (Star type FOG KABM) in to account when plotting the routes?
 

graham.reeds

G
Heater said:
All,

General question about the route planner and fuel scooping...
Does the route planner take the max jump range and scooping (Star type FOG KABM) in to account when plotting the routes?
Click to expand...

No. So scoop often.

What I do is slow to stop immediately after exiting hyperspace. This enables me to scan the sun and fire my space horn. While scanning I nudge myself closer until I am scooping but dont go above 100% heat. Takes a while but I am in no hurry.
 

Heater

Heater
graham.reeds said:
No. So scoop often.

What I do is slow to stop immediately after exiting hyperspace. This enables me to scan the sun and fire my space horn. While scanning I nudge myself closer until I am scooping but dont go above 100% heat. Takes a while but I am in no hurry.
Click to expand...


Thanks for the confirmation.
 

Jackie Silver

Jackie Silver
Here's a plot of those G-type star radii and temperatures:

gtypespectra.png

This confirms what we already suspected about the VB - VAB - VA classes with VA as the brightest.

It also shows (or at least implies very strongly, more data needed) that the G0 to G9 subdivisions are of precisely 80K width,
G9 is 5200K to 5280K
G8 is 5280K to 5360K
...and so on.

I looked at the blackbody temperature curves for a few similar G stars to see how broad a variation there is.

gtypesbbtemps.png

They're fairly close, but enough to make putting a precise figure on the habitable zones for a given subclass impractical. There's also a degree of overlap between adjacent bands; in this case one of the G4VAB and one of the G5VAB stars have almost identical curves.
(The curves follow T = Tstar * (Rstar**.05) / ((2*distance)**.05), which is effectively equal to a constant / ((2*distance)**.05). For any two stars where Tstar1 * (Rstar1**.05) = Tstar2 * (Rstar2**.05) the curves will be equal.)

This is a close-up of the habitable zones for those same stars:

gtypesbbtempszoom.png

I had a go at extrapolating backwards from my earlier data (which just had e.g. G2V, Earthlike at 1.08au) but there's too much variation for it to be useful so I'll have to collect new data. I could do the whole thing by tediously flicking between already explored systems around Sol but I'd rather explore! :D
 

Werppa

Werppa
Quick question again... What kind of star is WNCO I? I just fooled around in galaxy map and found it, seems that it's too far away for you to jump there.
 

Zeeman

Zeeman
Sssooo... Field Maintenance Units... I'm currently outfitting my exploration Asp... Can anyone tell me what benefit higher class/rating modules give me?

Been trying to search to figure it out, but it's doing my head in...


This is my target Asp loadout...

I like my guns and shields - Prefer to be able to fight back if need be... If for no other reason, than to survive long enough to get my FSD back online after an interdiction. I usually submit to them to save damage.

Z...
 
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