void generate_stellar_system()
{
planet_pointer planet;
radians_per_rotation = 2.0 * PI;
stellar_mass_ratio = random_number(0.6,1.3);
stellar_luminosity_ratio = luminosity(stellar_mass_ratio);
planet = distribute_planetary_masses(stellar_mass_ratio,stellar_luminosity_ratio,0.0,stellar_dust_limit(stellar_mass_ratio));
main_seq_life = 1.0E10 * (stellar_mass_ratio / stellar_luminosity_ratio);
if ((main_seq_life >= 6.0E9))
age = random_number(1.0E9,6.0E9);
else
age = random_number(1.0E9,main_seq_life);
r_ecosphere = sqrt(stellar_luminosity_ratio);
r_greenhouse = r_ecosphere * GREENHOUSE_EFFECT_CONST;
while (planet != NULL)
{
planet->orbit_zone = orbital_zone(planet->a);
if (planet->gas_giant)
{
planet->density = empirical_density(planet->mass,planet->a,planet->gas_giant);
planet->radius = volume_radius(planet->mass,planet->density);
}
else
{
planet->radius = kothari_radius(planet->mass,planet->a,planet->gas_giant,planet->orbit_zone);
planet->density = volume_density(planet->mass,planet->radius);
}
planet->orbital_period = period(planet->a,planet->mass,stellar_mass_ratio);
planet->day = day_length(planet->mass,planet->radius,planet->orbital_period,planet->e,planet->gas_giant);
planet->resonant_period = spin_resonance;
planet->axial_tilt = inclination(planet->a);
planet->escape_velocity = escape_vel(planet->mass,planet->radius);
planet->surface_accel = acceleration(planet->mass,planet->radius);
planet->rms_velocity = rms_vel(MOLECULAR_NITROGEN,planet->a);
planet->molecule_weight = molecule_limit(planet->a,planet->mass,planet->radius);
if ((planet->gas_giant))
{
planet->surface_grav = INCREDIBLY_LARGE_NUMBER;
planet->greenhouse_effect = FALSE;
planet->volatile_gas_inventory = INCREDIBLY_LARGE_NUMBER;
planet->surface_pressure = INCREDIBLY_LARGE_NUMBER;
planet->boil_point = INCREDIBLY_LARGE_NUMBER;
planet->hydrosphere = INCREDIBLY_LARGE_NUMBER;
planet->albedo = about(GAS_GIANT_ALBEDO,0.1);
planet->surface_temp = INCREDIBLY_LARGE_NUMBER;
}
else
{
planet->surface_grav = gravity(planet->surface_accel);
planet->greenhouse_effect = greenhouse(planet->orbit_zone,planet->a,r_greenhouse);
planet->volatile_gas_inventory = vol_inventory(planet->mass,planet->escape_velocity,planet->rms_velocity,stellar_mass_ratio,planet->orbit_zone,planet->greenhouse_effect);
planet->surface_pressure = pressure(planet->volatile_gas_inventory,planet->radius,planet->surface_grav);
if ((planet->surface_pressure == 0.0))
planet->boil_point = 0.0;
else
planet->boil_point = boiling_point(planet->surface_pressure);
iterate_surface_temp(&(planet));
}
planet = planet->next_planet;
}
display_system( );
}
stellar_system* generate_stellar_system(unsigned long random_seed)
{
planet* planet;
double outer_dust_limit;
stellar_system *system = malloc(sizeof(stellar_system));
system->first_planet = NULL;
setup_seed(system, random_seed);
system->star_mass_r = random_number(0.6, 1.3); /* was 0.6, 1.3 */
system->star_radius_r = about(pow(system->star_mass_r, 1.0 / 3.0), 0.05);
/* for some unknown reason, only 3 digits wanted... */
system->star_radius_r = floor(system->star_radius_r * 1000.0) / 1000.0;
system->star_lum_r = luminosity(system->star_mass_r);
/* luminosity is proportional to T^4 and to area of star */
/* so temp is Tsol * 4th-root ( Lum / r^2 ) */
system->star_temp = 5650 * sqrt(sqrt(system->star_lum_r) / system->star_radius_r);
/* ignore fractional degrees */
system->star_temp = floor(system->star_temp);
sprintf(system->star_class, "%.16s", find_star_class(system->star_temp));
outer_dust_limit = stellar_dust_limit(system->star_mass_r);
system->first_planet = distribute_planetary_masses(system, 0.0, outer_dust_limit);
system->main_seq_life = 1.0E10 * (system->star_mass_r / system->star_lum_r);
if (system->main_seq_life > 6.0E9)
system->star_age = random_number(1.0E9, 6.0E9);
else if (system->main_seq_life > 1.0E9)
system->star_age = random_number(1.0E9, system->main_seq_life);
else
system->star_age = random_number(system->main_seq_life/10, system->main_seq_life);
system->r_ecosphere = sqrt(system->star_lum_r);
system->r_greenhouse = system->r_ecosphere * GREENHOUSE_EFFECT_CONST;
for (planet = system->first_planet; planet != NULL; planet = planet->next_planet)
{
planet->orbit_zone = orbital_zone(system, planet->a);
if (planet->gas_giant)
{
planet->density = empirical_density(system, planet->mass, planet->a,
planet->gas_giant);
planet->radius = volume_radius(planet->mass, planet->density);
}
else
{
planet->radius = kothari_radius(planet->mass, planet->gas_giant,
planet->orbit_zone);
planet->density = volume_density(planet->mass, planet->radius);
}
planet->orb_period = period(planet->a, planet->mass, system->star_mass_r);
planet->day = day_length(system, planet->mass, planet->radius, planet->e,
planet->density, planet->a,
planet->orb_period, planet->gas_giant,
system->star_mass_r);
planet->resonant_period = system->resonance;
planet->axial_tilt = inclination(planet->a);
planet->esc_velocity = escape_velocity(planet->mass, planet->radius);
planet->surf_accel = acceleration(planet->mass, planet->radius);
planet->rms_velocity = rms_velocity(system, MOL_NITROGEN, planet->a);
planet->molec_weight = molecule_limit(planet->mass, planet->radius);
if ((planet->gas_giant))
{
planet->surf_grav = INCREDIBLY_LARGE_NUMBER;
planet->greenhouse_effect = false;
planet->volatile_gas_inventory = INCREDIBLY_LARGE_NUMBER;
planet->surf_pressure = INCREDIBLY_LARGE_NUMBER;
planet->boil_point = INCREDIBLY_LARGE_NUMBER;
planet->hydrosphere = INCREDIBLY_LARGE_NUMBER;
planet->albedo = about(GAS_GIANT_ALBEDO, 0.1);
planet->surf_temp = INCREDIBLY_LARGE_NUMBER;
}
else
{
planet->surf_grav = gravity(planet->surf_accel);
planet->greenhouse_effect = greenhouse(planet->orbit_zone, planet->a,
system->r_greenhouse);
planet->volatile_gas_inventory = vol_inventory(planet->mass,
planet->esc_velocity,
planet->rms_velocity,
system->star_mass_r,
planet->orbit_zone,
planet->greenhouse_effect);
planet->surf_pressure = pressure(planet->volatile_gas_inventory,
planet->radius, planet->surf_grav);
if (planet->surf_pressure == 0.0)
planet->boil_point = 0.0;
else
planet->boil_point = boiling_point(planet->surf_pressure);
iterate_surface_temp(system, &(planet));
}
#ifdef MOON
if (args.make_moon)
{
#ifdef PROPER_MOON
planet->first_moon = dist_moon_masses(planet->mass,
star_lum_r, planet->e,
0.0, planet_dust_limit(planet->mass));
#else
planet->first_moon = do_dist_moon_masses(planet->mass, planet->radius);
{
planet* moon = planet->first_moon;
while (moon)
{
moon->radius = kothari_radius(moon->mass, 0, planet->orbit_zone);
moon->density = volume_density(moon->mass, moon->radius);
moon->density = random_number(1.5, moon->density * 1.1);
if (moon->density < 1.5)
moon->density = 1.5;
moon->radius = volume_radius(moon->mass, moon->density);
moon->orb_period = period(moon->a, moon->mass, planet->mass);
moon->day = day_length(system, moon->mass, moon->radius, moon->e,
moon->density, moon->a,
moon->orb_period, moon->gas_giant,
planet->mass);
moon->resonant_period = system->resonance;
moon->axial_tilt = inclination(moon->a);
moon->esc_velocity = escape_vel(moon->mass, moon->radius);
moon->surf_accel = acceleration(moon->mass, moon->radius);
moon->rms_velocity = rms_vel(system, MOL_NITROGEN, planet->a);
moon->molec_weight = molecule_limit(moon->mass, moon->radius);
moon->surf_grav = gravity(moon->surf_accel);
moon->greenhouse_effect = grnhouse(planet->orbit_zone,
planet->a,
system->r_greenhouse);
moon->volatile_gas_inventory = vol_inventory(moon->mass,
moon->esc_velocity,
moon->rms_velocity,
system->star_mass_r,
planet->orbit_zone,
moon->greenhouse_effect);
moon->surf_pressure = pressure(moon->volatile_gas_inventory,
moon->radius, moon->surf_grav);
if ((moon->surf_pressure == 0.0))
moon->boil_point = 0.0;
else
moon->boil_point = boiling_point(moon->surf_pressure);
iterate_surface_temp_moon(system, &planet, &moon);
moon = moon->next_planet;
}
}
#endif /* CC_MOON */
}
#endif /* MOON */
}
return system;
}
main()
{
int year,month,day;
double lon, lat;
double daylen, civlen, nautlen, astrlen;
double rise, set, civ_start, civ_end, naut_start, naut_end,
astr_start, astr_end;
int rs, civ, naut, astr;
char buf[80];
printf( "Longitude (+ is east) and latitude (+ is north) : " );
fgets(buf, 80, stdin);
sscanf(buf, "%lf %lf", &lon, &lat );
for(;;)
{
printf( "Input date ( yyyy mm dd ) (ctrl-C exits): " );
fgets(buf, 80, stdin);
sscanf(buf, "%d %d %d", &year, &month, &day );
daylen = day_length(year,month,day,lon,lat);
civlen = day_civil_twilight_length(year,month,day,lon,lat);
nautlen = day_nautical_twilight_length(year,month,day,lon,lat);
astrlen = day_astronomical_twilight_length(year,month,day,
lon,lat);
printf( "Day length: %5.2f hours\n", daylen );
printf( "With civil twilight %5.2f hours\n", civlen );
printf( "With nautical twilight %5.2f hours\n", nautlen );
printf( "With astronomical twilight %5.2f hours\n", astrlen );
printf( "Length of twilight: civil %5.2f hours\n",
(civlen-daylen)/2.0);
printf( " nautical %5.2f hours\n",
(nautlen-daylen)/2.0);
printf( " astronomical %5.2f hours\n",
(astrlen-daylen)/2.0);
rs = sun_rise_set ( year, month, day, lon, lat,
&rise, &set );
civ = civil_twilight ( year, month, day, lon, lat,
&civ_start, &civ_end );
naut = nautical_twilight ( year, month, day, lon, lat,
&naut_start, &naut_end );
astr = astronomical_twilight( year, month, day, lon, lat,
&astr_start, &astr_end );
printf( "Sun at south %5.2fh UT\n", (rise+set)/2.0 );
switch( rs )
{
case 0:
printf( "Sun rises %5.2fh UT, sets %5.2fh UT\n",
rise, set );
break;
case +1:
printf( "Sun above horizon\n" );
break;
case -1:
printf( "Sun below horizon\n" );
break;
}
switch( civ )
{
case 0:
printf( "Civil twilight starts %5.2fh, "
"ends %5.2fh UT\n", civ_start, civ_end );
break;
case +1:
printf( "Never darker than civil twilight\n" );
break;
case -1:
printf( "Never as bright as civil twilight\n" );
break;
}
switch( naut )
{
case 0:
printf( "Nautical twilight starts %5.2fh, "
"ends %5.2fh UT\n", naut_start, naut_end );
break;
case +1:
printf( "Never darker than nautical twilight\n" );
break;
case -1:
printf( "Never as bright as nautical twilight\n" );
break;
}
switch( astr )
{
case 0:
printf( "Astronomical twilight starts %5.2fh, "
"ends %5.2fh UT\n", astr_start, astr_end );
break;
case +1:
printf( "Never darker than astronomical twilight\n" );
break;
case -1:
printf( "Never as bright as astronomical twilight\n" );
break;
}
return 0;
}
}
main()
{
int year,month,day;
double lon, lat;
double daylen, civlen, nautlen, astrlen;
double rise, set, civ_start, civ_end, naut_start, naut_end,
astr_start, astr_end;
double daylen_int,daylen_frac; /* CWR */
int rs, civ, naut, astr;
int daylen_hours,daylen_min, gmtoff_hr; /* cwr */
double rise_int,rise_frac,set_int,set_frac;
int rise_hours,rise_min,set_hours,set_min;
time_t the_time; /* only need so can get time zone of local machine... */
struct tm *mylocal_time;
char buf[80];
/* get time and offset from GMT */
time(&the_time);
mylocal_time = localtime(&the_time);
gmtoff_hr = mylocal_time->tm_gmtoff/3600;
printf("Enter longitude and latitude in decimal degrees, i.e. -97.75 30.23\n");
printf("Hint: divide minutes by 60 to get decimal portion\n");
printf( "Longitude (+ is east) and latitude (+ is north) : " );
fgets(buf, 80, stdin);
sscanf(buf, "%lf %lf", &lon, &lat );
for(;;)
{
printf( "Input date ( yyyy mm dd ) (ctrl-C exits): " );
fgets(buf, 80, stdin);
sscanf(buf, "%d %d %d", &year, &month, &day );
daylen = day_length(year,month,day,lon,lat);
civlen = day_civil_twilight_length(year,month,day,lon,lat);
nautlen = day_nautical_twilight_length(year,month,day,lon,lat);
astrlen = day_astronomical_twilight_length(year,month,day,
lon,lat);
daylen_frac = modf(daylen,&daylen_int); /* daylen into int and fraction */
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( "Day length: %5.2f hours", daylen );
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
daylen_frac = modf(civlen,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( "With civil twilight %5.2f hours", civlen );
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
daylen_frac = modf(nautlen,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( "With nautical twilight %5.2f hours", nautlen );
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
daylen_frac = modf(astrlen,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( "With astronomical twilight %5.2f hours", astrlen );
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
daylen_frac = modf((civlen-daylen)/2.0,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( "Length of twilight: civil %5.2f hours",
(civlen-daylen)/2.0);
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
daylen_frac = modf((nautlen-daylen)/2.0,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( " nautical %5.2f hours",
(nautlen-daylen)/2.0);
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
daylen_frac = modf((astrlen-daylen)/2.0,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( " astronomical %5.2f hours",
(astrlen-daylen)/2.0);
printf( "(%2d hours %2d min)\n", daylen_hours,daylen_min );
rs = sun_rise_set ( year, month, day, lon, lat,
&rise, &set );
civ = civil_twilight ( year, month, day, lon, lat,
&civ_start, &civ_end );
naut = nautical_twilight ( year, month, day, lon, lat,
&naut_start, &naut_end );
astr = astronomical_twilight( year, month, day, lon, lat,
&astr_start, &astr_end );
daylen_frac = modf(((rise+set)/2.0)+gmtoff_hr ,&daylen_int);
daylen_hours = (int)daylen_int;
daylen_min = (int)(daylen_frac * 60);
printf( "Sun at south %5.2fh UT,%20d:%02d local\n", (rise+set)/2.0,daylen_hours,daylen_min);
switch( rs )
{
case 0:
/* add minutes and local. CWR*/
rise_frac = modf(rise+gmtoff_hr ,&rise_int);
rise_hours = (int)rise_int;
rise_min = (int)(rise_frac * 60);
set_frac = modf(set+gmtoff_hr ,&set_int);
set_hours = (int)set_int;
set_min = (int)(set_frac * 60);
printf( "Sun rises %5.2fh UT, sets %5.2fh UT;\n rises %02d:%02d, sets %02d:%02d local\n",
rise, set, rise_hours,rise_min,set_hours,set_min);
break;
case +1:
printf( "Sun above horizon\n" );
break;
case -1:
printf( "Sun below horizon\n" );
break;
}
switch( civ )
{
case 0:
rise_frac = modf(civ_start+gmtoff_hr ,&rise_int);
rise_hours = (int)rise_int;
rise_min = (int)(rise_frac * 60);
set_frac = modf(civ_end+gmtoff_hr ,&set_int);
set_hours = (int)set_int;
set_min = (int)(set_frac * 60);
printf( "Civil twilight starts %5.2fh, "
"ends %5.2fh UT;\n starts %02d:%02d, ends %02d:%02d local\n",
civ_start, civ_end,
rise_hours, rise_min, set_hours, set_min);
break;
case +1:
printf( "Never darker than civil twilight\n" );
break;
case -1:
printf( "Never as bright as civil twilight\n" );
break;
}
switch( naut )
{
case 0:
rise_frac = modf(naut_start+gmtoff_hr ,&rise_int);
rise_hours = (int)rise_int;
rise_min = (int)(rise_frac * 60);
set_frac = modf(naut_end+gmtoff_hr ,&set_int);
set_hours = (int)set_int;
set_min = (int)(set_frac * 60);
printf( "Nautical twilight starts %5.2fh, "
"ends %5.2fh UT;\n starts %02d:%02d, ends %02d:%02d local\n",
naut_start, naut_end,
rise_hours, rise_min, set_hours, set_min );
break;
case +1:
printf( "Never darker than nautical twilight\n" );
break;
case -1:
printf( "Never as bright as nautical twilight\n" );
break;
}
switch( astr )
{
case 0:
rise_frac = modf(astr_start+gmtoff_hr ,&rise_int);
rise_hours = (int)rise_int;
rise_min = (int)(rise_frac * 60);
set_frac = modf(astr_end+gmtoff_hr ,&set_int);
set_hours = (int)set_int;
set_min = (int)(set_frac * 60);
printf( "Astronomical twilight starts %5.2fh, "
"ends %5.2fh UT;\n starts %02d:%02d, ends %02d:%02d local\n",
astr_start, astr_end,
rise_hours, rise_min, set_hours, set_min );
break;
case +1:
printf( "Never darker than astronomical twilight\n" );
break;
case -1:
printf( "Never as bright as astronomical twilight\n" );
break;
}
return 0;
}
}
int
main (void)
{
int year, month, day;
double lon, lat;
double len, rise, set, cur_time;
int rc;
char ch;
time_t t;
struct tm *tm;
t = time (NULL);
tm = gmtime (&t);
lon = 0;
sun_rise_set (tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
lon, 0.0, &rise, &set);
cur_time = tm->tm_hour + tm->tm_min / 60.0;
lon += (rise - cur_time) * 15.0;
if (lon > 180.0)
lon -= 360.0;
if (lon < -180.0)
lon += 360.0;
printf ("==> Sun is rising at longitude %5.2fE, latitude 0.00N\n", lon);
printf ("Longitude (+ is east) and latitude (+ is north), or * for Lugano: ");
ch = getchar ();
if (ch == '*')
lon = 8.0 + 57.0/60.0, lat = 46.0;
else
{
ungetc (ch, stdin);
while (scanf ("%lf %lf", &lon, &lat) < 2)
;
}
tm = localtime (&t);
year = tm->tm_year + 1900;
month = tm->tm_mon + 1;
day = tm->tm_mday;
do
{
len = day_length (year, month, day, lon, lat);
printf ("==> Day length: %5.2f hours\n", len);
rc = sun_rise_set (year, month, day, lon, lat, &rise, &set);
if (rc == 1)
printf ("==> Sun never sets!\n");
else if (rc == -1)
printf ("==> Sun never rises!\n");
else
{
printf ("==> Midday: %5.2f GMT\n", (rise + set) / 2);
printf ("==> Sunrise: %5.2f, Sunset: %5.2f GMT\n", rise, set);
}
rc = civil_rise_set (year, month, day, lon, lat, &rise, &set);
if (rc == 1)
printf ("==> Sun never reaches civil dusk!\n");
else if (rc == -1)
printf ("==> Sun never reaches civil dawn!\n");
else
printf ("==> Civil sunrise: %5.2f, Sunset: %5.2f GMT\n", rise, set);
printf ("Date (yyyy mm dd) (ctrl-C exits): ");
while (scanf ("%d %d %d", &year, &month, &day) < 3 && !feof (stdin))
;
}
while (!feof (stdin));
return 0;
}
