Star and System Design

This file is licensed under the Creative Commons Attribution ShareAlike 2.5 License. In short: you are free to share and make derivative works of the file under the conditions that you appropriately attribute it, and that you distribute it only under a license identical to this one. Taken from Wikipedia, stars

This game has a large database of stars and their data. This data is generated using a torus filled with high contrast Perlin noise star positions and a star system generator based on known probabilities of stars and planets and other orbiting bodies in the area of Sol. The stars are in very large open cluster numbering about 28,000 objects in total. The open cluster is believed to have evolved from a smoke ring shaped nebula.

Here is the math do calculate the habitable zone. Only planets in the HZ will have randomly generated life forms, others must me placed by the Game masters. http://en.wikipedia.org/wiki/Habitable_zone

Here is a great link to info about making systems by Tyge Sjostrand . I am sure we can use most of it.
http://www.trisen.com/sol/static/wg/wg.html

Info in the Star data base entry:
ID
Game Master (default sysop)
Game Master Group
Game Master Other
Player (default sysop)
Player Group
Player Other
Star Name
X
Y
Z
Number Of Companions.
List of companion IDs

Spectral Type
Luminosity 1 (sol L)
Mass (sol mass)
Temperature
Metallicity
Absolute Magnitude
Main Sequence Duration (Gyr)
HabZone Inner Radius (AU)
HabZone Outer Radius (AU)
Jump Out Distance
Jump In Distance
Tidal locking Outer Radius (AU)
Number of objects (planets) in primary orbit
list of pointers to (objects) planets
list of possible jump to systems
dates and times each jump system last changed state
list of active jump to systems
Last ship to vist
Date of last vist.
Average number of visits per week.

id | owner_id | owner_read | owner_write | group_id | group_read | group_write | other_read | other_write | star_name | short_description | long_description | picture | orbital_degrees | orbital_radius | orbital_speed | x | y | z | spectral_class | spectral_subclass | star_size | bolometric_magnitude | luminosity | effective_temperatures | mass | radii | inner_habitable_zone | outer_habitable_zone | number_of_planets | planet_id | number_of_objects_in_orbit | objects_id | number_of_animals | animals | number_of_plants | plants

Info in the Planet data base entry:
ID
Game Master (default sysop)
Game Master Group
Game Master Other
Player (default none)
Player Group
Player Other
Planet Name
Planet Mass (J mass)
Planet Surface Gravity
Planet Percent Water
Planet Semi axis (AU)
Orbital Ecc.
Orbital Period (sidereal days)
Orbit of Greatest Opp. (AU)
Planet Start Category
Planet's Residency in Habitable Zone (Gyr)
Tidal locking Outer Radius (AU)

Number of objects (planets) in primary orbit
list of pointers to (objects) planets

This bit is from a web site http://www.solstation.com/habitable.htm but is very relevant for the design of our system generator.

The range of star types that can support Earth-type life on planets may be limited to those lower mass stars that "live" long enough as stable luminous stars for planets to form and complex life to evolve. Although all main sequence stars generate luminous energy by converting hydrogen into helium through thermonuclear fusion, stars more massive than 1.5 times that of Sol (i.e., stars of spectral type O, B, or A dwarfs like Sirius) age too quickly to support the development of complex Earth-type life. Even the largest, possibly suitable stars — i.e., spectral type F0-4 (Kasting et al, 1993; abstract) — may only be able to support Earth-type life for around two billion years, and so planets in favorable orbits may not have sufficient time to develop complex life on land such as trees. Moreover, within a couple of billion years of a star's birth, cometary and asteroidal bombardment may still be so intense that living on such planets would be quite risky.

NASA Observatorium

See a discussion of
the "main sequence"
as part of stellar
evolution and death.

On the opposite extreme, stars with less than half of Sol's mass (e.g., smaller spectral type M dwarfs like Proxima Centauri) are more likely to tidally lock planets that are orbiting close enough to have liquid water on their surface too quickly, before life can develop (Peale, 1977). Tidally locking (or synchronous rotation of the star and planet) may eventually cause the destruction of a life-sustaining atmosphere through condensation on the cold, perpetually dark side of the planet. Moreover, most M-type red dwarf stars would tend to sterilize life on a close-orbiting Earth-type planet regularly with large stellar flares. Therefore, NASA's proposed Kepler Mission will search for habitable planets at nearby main sequence stars that are less massive than spectral type A but more massive than type M — dwarf stars of types F, G, and K. However, since low-mass M- and K-type stars so numerous, some astronomers and planetary scientists are continuing to model low-mass stars and possible planetary environments that may be potentially suitable for Earth-type plant and animal life, as well as for microbes (Helmut Hammer, 2007; Tarter et al, 2007; Scalo et al, 2007; Khodachenko et al, 2007; and Grenfell et al, 2007; and Kiang et al, 2007).