Number of habitable worlds within170 light years?

[cupbearer]

Hi,

I know nobody can really answer this with true certainty, but what do you think a reasonable amount of habitable worlds would be to place in a campaign if you traveled in every direction up to 170 light years away?

[JulianLW]

There are more than 60 G-type stars (like Sol) within 50 parsecs (just under 170 ly) from Earth:

http://www.solstation.com/stars3/100-gs.htm

There are many many many M-type stars (Red Dwarfs likely to have habitable zones) within 50 parsecs. It's up for debate, though, whether these stars are really likely to have habitable worlds:

http://www.solstation.com/stars3/100-ms.htm#40-50

And maybe the likeliest to have habitable worlds are K-type stars, with an estimated >200 within 50 ly and maybe as many as 2,000 within 100 ly.

http://www.solstation.com/stars3/100-ks.htm

Hope these pages help!

EDIT: In other words, probably far, far more than it would be possible to stat for any playable game! Guesstimate 10% of these stars host habitable worlds and you're still looking at more than a thousand habitable worlds within 50 parsecs at the very least.

[Agemegos]

I ran the GURPS Space generator over data from the XHIP catalogue. Disregarding a lot of synchronously-rotating planets of M and late K stars that I didn’t think would actually be habitable, and adopting a somewhat higher bar for habitability than the standard Habitability rating, I got one thousand habitable planets within 175 light years.

That’s optimistic, but not incredible.

[cupbearer]

Originally Posted by Agemegos

I ran the GURPS Space generator over data from the XHIP catalogue. Disregarding a lot of synchronously-rotating planets of M and late K stars that I didn’t think would actually be habitable, and adopting a somewhat higher bad for habitability than the standard Habitability rating, I got one thouasnd habitable planets within 155 light years.

That’s optimistic, but not incredible.

Awesome thank you

[Anthony]

A lot depends on your definition of habitable, and on some assumptions (I would note that Earth has not been human-habitable for most of its lifespan, and we have far less information about alien planets)

[Phantasm]

I use K, G, and F type stars for hunting down habitable worlds. A generous estimate is likely to be 50% of the stars have a planet in the habitable zone, with 50% of those planets being habitable without some form of terraforming.

That said, in my own space opera setting I have a habitable planet in each of those that has a stable zone (F types with orbiting white dwarfs - like Procyon - don't count) - and even those whose planets aren't habitable still get inhabited by humans in pressure domes. So even the M-types are inhabited, even if not inhabitable.

(A-types like Vega aren't likely to have habitable planets, due to being too young, if they have planets in the first place.)

[Agemegos]

Originally Posted by Anthony

(I would note that Earth has not been human-habitable for most of its lifespan…)

What, because of the lack of oxygen and toxic concentration of CO₂ in the atmosphere?

Little thing like that!

[cupbearer]

Originally Posted by JulianLW

There are more than 60 G-type stars (like Sol) within 50 parsecs (just under 170 ly) from Earth:

http://www.solstation.com/stars3/100-gs.htm

There are many many many M-type stars (Red Dwarfs likely to have habitable zones) within 50 parsecs. It's up for debate, though, whether these stars are really likely to have habitable worlds:

http://www.solstation.com/stars3/100-ms.htm#40-50

And maybe the likeliest to have habitable worlds are K-type stars, with an estimated >200 within 50 ly and maybe as many as 2,000 within 100 ly.

http://www.solstation.com/stars3/100-ks.htm

Hope these pages help!

EDIT: In other words, probably far, far more than it would be possible to stat for any playable game! Guesstimate 10% of these stars host habitable worlds and you're still looking at more than a thousand habitable worlds within 50 parsecs at the very least.

Thank you very much