G4V Star System Generated (Seed: 1766256360)
Star Details
Spectral Class: G8V
Temperature: 5,360 K
Mass: 0.94 sol
Luminosity: 0.81 lux
Habitable Zone (HZ)
Inner Boundary: 0.86 AU
Outer Boundary: 1.24 AU
Physical Limits
Snow Line: 4.32 AU
Max System Radius: 19.4 AU
Planetary System (9 Planets)
Asteroid Belt
Center: 0.53 AU
Composition
Type: Inner System (Rocky)
A dense region of planetesimals and debris.
Boundary
Planet 1 - Terrestrial
Semi-Major Axis: 1.06 AU
Status: HZ
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 4.63
Radius: 1.85
Gravity: 1.35 G
Time & Orbit
Eccentricity (e): 0.137
Orbit Range: 0.91 AU - 1.21 AU
Year: 411 Days
Day: 22.8 Hours
Environment
Temp: 0 °C
Axial Tilt: 114.8 °
Atmosphere: Nâ‚‚, Oâ‚‚
Biome: Oceanic/Continental
Satellites (1)
Outer Limit: 85,143,325 km
- M1: 512,822 km (0.091 R)
Planet 2 - Terrestrial
Semi-Major Axis: 1.13 AU
Status: HZ
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 2.01
Radius: 1.32
Gravity: 1.15 G
Time & Orbit
Eccentricity (e): 0.153
Orbit Range: 0.96 AU - 1.3 AU
Year: 453 Days
Day: 25.7 Hours
Environment
Temp: 6 °C
Axial Tilt: 35 °
Atmosphere: Nâ‚‚, Oâ‚‚
Biome: Oceanic/Continental
Planet 3 - Terrestrial
Semi-Major Axis: 1.64 AU
Status: Outer (Cold)
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 1.61
Radius: 1.21
Gravity: 1.1 G
Time & Orbit
Eccentricity (e): 0.223
Orbit Range: 1.27 AU - 2.01 AU
Year: 791 Days
Day: 33 Hours
Environment
Temp: -63 °C
Axial Tilt: 6.4 °
Atmosphere: Thin Nâ‚‚/CHâ‚„
Biome: Ice Cap/Desert
Satellites (2)
Outer Limit: 85,143,325 km
- M1: 620,682 km (0.107 R)
- M2: 947,254 km (0.105 R)
Planet 4 - Terrestrial
Semi-Major Axis: 3.75 AU
Status: Outer (Cold)
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 1.02
Radius: 1.01
Gravity: 1 G
Time & Orbit
Eccentricity (e): 0.235
Orbit Range: 2.87 AU - 4.63 AU
Year: 2736 Days
Day: 29 Hours
Environment
Temp: -124 °C
Axial Tilt: 7.7 °
Atmosphere: Thin Nâ‚‚/CHâ‚„
Biome: Ice Cap/Desert
Satellites (1)
Outer Limit: 85,143,325 km
- M1: 998,267 km (0.116 R)
Asteroid Belt
Center: 4.93 AU
Composition
Type: Main (Rocky/Icy Mix)
A dense region of planetesimals and debris.
Boundary
Planet 5 - Gas Giant
Semi-Major Axis: 6.11 AU
Status: Outer (Cold)
Composition: Hydrogen/Helium Atmosphere
Physical Data
Mass: 34.5
Radius: 14.2
Gravity: 0.17 G
Time & Orbit
Eccentricity (e): 0.199
Orbit Range: 4.89 AU - 7.33 AU
Year: 5690 Days
Day: 8.9 Hours
Environment
Temp: -152 °C
Axial Tilt: 26.2 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (32)
Outer Limit: 85,143,325 km
- M1: 298,597 km (0.025 R)
- M2: 680,670 km (0.06 R)
- M3: 1,091,316 km (0.108 R)
- M4: 1,746,256 km (0.092 R)
- M5: 1,951,205 km (0.09 R)
- M6: 2,304,256 km (0.04 R)
- M7: 3,321,073 km (0.055 R)
- M8: 3,565,815 km (0.086 R)
- M9: 3,950,132 km (0.056 R)
- M10: 4,259,799 km (0.05 R)
- M11: 4,668,052 km (0.06 R)
- M12: 5,022,300 km (0.113 R)
- M13: 5,426,364 km (0.096 R)
- M14: 5,869,173 km (0.104 R)
- M15: 6,109,128 km (0.107 R)
- M16: 6,251,845 km (0.109 R)
- M17: 6,526,058 km (0.062 R)
- M18: 7,116,520 km (0.079 R)
- M19: 7,433,518 km (0.119 R)
- M20: 7,540,181 km (0.036 R)
- M21: 7,878,721 km (0.099 R)
- M22: 8,587,067 km (0.103 R)
- M23: 8,747,287 km (0.119 R)
- M24: 8,989,486 km (0.097 R)
- M25: 9,447,405 km (0.081 R)
- M26: 9,696,036 km (0.118 R)
- M27: 9,829,478 km (0.076 R)
- M28: 10,081,251 km (0.065 R)
- M29: 10,420,539 km (0.087 R)
- M30: 10,557,271 km (0.096 R)
- M31: 11,284,915 km (0.117 R)
- M32: 11,443,040 km (0.076 R)
Planet 6 - Gas Giant
Semi-Major Axis: 6.24 AU
Status: Outer (Cold)
Composition: Hydrogen/Helium Atmosphere
Physical Data
Mass: 476.4
Radius: 10.5
Gravity: 4.32 G
Time & Orbit
Eccentricity (e): 0.101
Orbit Range: 5.61 AU - 6.87 AU
Year: 5872 Days
Day: 11.6 Hours
Environment
Temp: -155 °C
Axial Tilt: 95.1 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (83)
Outer Limit: 85,143,325 km
- M1: 144,362 km (0.066 R)
- M2: 277,055 km (0.072 R)
- M3: 492,327 km (0.118 R)
- M4: 715,377 km (0.086 R)
- M5: 1,068,129 km (0.057 R)
- M6: 1,139,337 km (0.115 R)
- M7: 1,301,950 km (0.075 R)
- M8: 1,504,356 km (0.106 R)
- M9: 1,904,979 km (0.12 R)
- M10: 2,135,958 km (0.076 R)
- M11: 2,319,814 km (0.089 R)
- M12: 2,547,502 km (0.092 R)
- M13: 2,703,383 km (0.104 R)
- M14: 2,842,360 km (0.094 R)
- M15: 3,379,715 km (0.093 R)
- M16: 3,594,837 km (0.048 R)
- M17: 3,660,361 km (0.103 R)
- M18: 3,903,756 km (0.088 R)
- M19: 4,084,022 km (0.054 R)
- M20: 4,198,165 km (0.057 R)
- M21: 4,453,080 km (0.095 R)
- M22: 4,713,081 km (0.087 R)
- M23: 5,051,322 km (0.106 R)
- M24: 5,472,589 km (0.075 R)
- M25: 6,269,946 km (0.117 R)
- M26: 6,615,218 km (0.112 R)
- M27: 6,939,396 km (0.104 R)
- M28: 7,048,603 km (0.071 R)
- M29: 7,351,987 km (0.068 R)
- M30: 7,463,288 km (0.113 R)
- M31: 7,631,436 km (0.046 R)
- M32: 8,637,183 km (0.111 R)
- M33: 8,843,329 km (0.1 R)
- M34: 9,320,695 km (0.109 R)
- M35: 9,745,254 km (0.096 R)
- M36: 9,837,107 km (0.063 R)
- M37: 10,207,212 km (0.065 R)
- M38: 10,644,786 km (0.049 R)
- M39: 11,024,765 km (0.089 R)
- M40: 11,441,544 km (0.073 R)
- M41: 12,522,539 km (0.056 R)
- M42: 12,756,061 km (0.108 R)
- M43: 12,957,270 km (0.115 R)
- M44: 13,058,249 km (0.057 R)
- M45: 13,295,062 km (0.091 R)
- M46: 13,431,046 km (0.095 R)
- M47: 14,014,029 km (0.118 R)
- M48: 14,256,527 km (0.106 R)
- M49: 14,325,941 km (0.068 R)
- M50: 15,275,738 km (0.047 R)
- M51: 15,704,336 km (0.109 R)
- M52: 15,812,046 km (0.073 R)
- M53: 16,100,620 km (0.032 R)
- M54: 16,245,581 km (0.095 R)
- M55: 16,976,965 km (0.041 R)
- M56: 17,161,419 km (0.074 R)
- M57: 17,235,470 km (0.095 R)
- M58: 17,495,321 km (0.116 R)
- M59: 17,868,718 km (0.1 R)
- M60: 18,282,505 km (0.101 R)
- M61: 18,890,172 km (0.086 R)
- M62: 19,119,655 km (0.117 R)
- M63: 20,086,057 km (0.116 R)
- M64: 20,242,237 km (0.079 R)
- M65: 20,634,184 km (0.086 R)
- M66: 21,107,960 km (0.081 R)
- M67: 21,705,155 km (0.056 R)
- M68: 21,905,616 km (0.075 R)
- M69: 21,985,801 km (0.063 R)
- M70: 22,146,768 km (0.101 R)
- M71: 23,120,351 km (0.112 R)
- M72: 23,777,235 km (0.093 R)
- M73: 23,942,391 km (0.065 R)
- M74: 24,149,285 km (0.062 R)
- M75: 25,235,366 km (0.085 R)
- M76: 26,081,491 km (0.105 R)
- M77: 26,851,023 km (0.091 R)
- M78: 27,454,650 km (0.076 R)
- M79: 27,758,184 km (0.064 R)
- M80: 27,932,166 km (0.087 R)
- M81: 28,150,131 km (0.05 R)
- M82: 29,204,048 km (0.054 R)
- M83: 29,425,303 km (0.119 R)
Planet 7 - Gas Giant
Semi-Major Axis: 6.47 AU
Status: Outer (Cold)
Composition: Hydrogen/Helium Atmosphere
Physical Data
Mass: 247.2
Radius: 13.8
Gravity: 1.3 G
Time & Orbit
Eccentricity (e): 0.041
Orbit Range: 6.2 AU - 6.74 AU
Year: 6200 Days
Day: 5.5 Hours
Environment
Temp: -169 °C
Axial Tilt: 3.7 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (73)
Outer Limit: 85,143,325 km
- M1: 173,833 km (0.071 R)
- M2: 398,978 km (0.1 R)
- M3: 561,291 km (0.08 R)
- M4: 837,000 km (0.074 R)
- M5: 962,513 km (0.046 R)
- M6: 1,208,751 km (0.115 R)
- M7: 1,421,180 km (0.119 R)
- M8: 1,763,460 km (0.09 R)
- M9: 1,868,328 km (0.116 R)
- M10: 1,975,589 km (0.115 R)
- M11: 2,164,232 km (0.115 R)
- M12: 2,425,430 km (0.07 R)
- M13: 2,576,823 km (0.093 R)
- M14: 2,766,513 km (0.069 R)
- M15: 3,086,952 km (0.067 R)
- M16: 3,251,809 km (0.116 R)
- M17: 3,783,480 km (0.118 R)
- M18: 3,960,304 km (0.079 R)
- M19: 4,079,684 km (0.095 R)
- M20: 4,322,182 km (0.075 R)
- M21: 4,507,234 km (0.104 R)
- M22: 4,970,838 km (0.058 R)
- M23: 5,164,866 km (0.097 R)
- M24: 5,875,456 km (0.051 R)
- M25: 6,288,795 km (0.097 R)
- M26: 6,499,130 km (0.047 R)
- M27: 6,974,702 km (0.074 R)
- M28: 7,119,662 km (0.116 R)
- M29: 7,338,972 km (0.112 R)
- M30: 7,610,044 km (0.069 R)
- M31: 8,212,923 km (0.09 R)
- M32: 8,675,330 km (0.114 R)
- M33: 8,935,930 km (0.052 R)
- M34: 9,384,873 km (0.051 R)
- M35: 9,787,141 km (0.113 R)
- M36: 9,922,528 km (0.104 R)
- M37: 10,085,739 km (0.082 R)
- M38: 10,775,684 km (0.053 R)
- M39: 10,999,782 km (0.055 R)
- M40: 11,168,827 km (0.055 R)
- M41: 11,281,923 km (0.096 R)
- M42: 11,480,889 km (0.087 R)
- M43: 11,940,154 km (0.049 R)
- M44: 12,434,725 km (0.099 R)
- M45: 12,728,834 km (0.046 R)
- M46: 12,847,016 km (0.04 R)
- M47: 13,624,776 km (0.105 R)
- M48: 13,958,529 km (0.11 R)
- M49: 14,975,644 km (0.096 R)
- M50: 15,131,825 km (0.103 R)
- M51: 15,225,922 km (0.12 R)
- M52: 15,667,086 km (0.101 R)
- M53: 15,825,660 km (0.114 R)
- M54: 16,176,467 km (0.088 R)
- M55: 16,788,471 km (0.113 R)
- M56: 16,918,322 km (0.102 R)
- M57: 17,441,017 km (0.054 R)
- M58: 17,803,343 km (0.069 R)
- M59: 17,935,738 km (0.059 R)
- M60: 18,703,474 km (0.09 R)
- M61: 19,108,286 km (0.101 R)
- M62: 19,857,921 km (0.109 R)
- M63: 20,167,439 km (0.078 R)
- M64: 20,409,189 km (0.103 R)
- M65: 20,756,405 km (0.115 R)
- M66: 21,245,590 km (0.059 R)
- M67: 21,668,055 km (0.09 R)
- M68: 22,164,421 km (0.098 R)
- M69: 22,700,280 km (0.062 R)
- M70: 23,967,524 km (0.059 R)
- M71: 24,150,482 km (0.093 R)
- M72: 24,297,088 km (0.103 R)
- M73: 24,554,396 km (0.066 R)
Planet 8 - Ice Giant
Semi-Major Axis: 15.29 AU
Status: Outer (Cold)
Composition: Methane/Ammonia Ices
Physical Data
Mass: 820.6
Radius: 5.8
Gravity: 24.39 G
Time & Orbit
Eccentricity (e): 0.034
Orbit Range: 14.77 AU - 15.81 AU
Year: 22524 Days
Day: 15.7 Hours
Environment
Temp: -206 °C
Axial Tilt: 8.6 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (95)
Outer Limit: 85,143,325 km
- M1: 1,138,589 km (0.071 R)
- M2: 1,388,867 km (0.105 R)
- M3: 1,487,152 km (0.05 R)
- M4: 1,795,922 km (0.11 R)
- M5: 2,199,986 km (0.11 R)
- M6: 2,877,515 km (0.092 R)
- M7: 2,961,290 km (0.118 R)
- M8: 3,348,150 km (0.091 R)
- M9: 4,311,411 km (0.099 R)
- M10: 4,407,452 km (0.114 R)
- M11: 4,848,018 km (0.068 R)
- M12: 5,509,241 km (0.086 R)
- M13: 5,876,803 km (0.089 R)
- M14: 6,198,289 km (0.069 R)
- M15: 7,656,120 km (0.091 R)
- M16: 8,422,959 km (0.073 R)
- M17: 8,907,057 km (0.083 R)
- M18: 9,029,428 km (0.115 R)
- M19: 9,649,960 km (0.09 R)
- M20: 9,902,033 km (0.096 R)
- M21: 10,092,471 km (0.109 R)
- M22: 10,997,239 km (0.109 R)
- M23: 12,130,293 km (0.113 R)
- M24: 12,198,061 km (0.064 R)
- M25: 12,676,325 km (0.111 R)
- M26: 13,721,416 km (0.078 R)
- M27: 13,792,176 km (0.029 R)
- M28: 14,794,033 km (0.108 R)
- M29: 15,377,016 km (0.109 R)
- M30: 15,523,921 km (0.108 R)
- M31: 16,490,323 km (0.099 R)
- M32: 16,791,613 km (0.034 R)
- M33: 17,552,617 km (0.103 R)
- M34: 17,629,361 km (0.081 R)
- M35: 18,636,903 km (0.108 R)
- M36: 20,142,755 km (0.107 R)
- M37: 21,113,795 km (0.112 R)
- M38: 21,358,986 km (0.107 R)
- M39: 21,769,632 km (0.052 R)
- M40: 23,946,730 km (0.039 R)
- M41: 25,755,218 km (0.085 R)
- M42: 25,842,434 km (0.078 R)
- M43: 26,985,062 km (0.105 R)
- M44: 27,251,047 km (0.051 R)
- M45: 27,517,930 km (0.092 R)
- M46: 28,144,147 km (0.095 R)
- M47: 28,594,287 km (0.05 R)
- M48: 28,684,494 km (0.067 R)
- M49: 28,956,014 km (0.102 R)
- M50: 29,046,671 km (0.1 R)
- M51: 29,867,215 km (0.027 R)
- M52: 30,050,472 km (0.072 R)
- M53: 31,437,544 km (0.042 R)
- M54: 31,904,439 km (0.116 R)
- M55: 32,279,780 km (0.095 R)
- M56: 39,580,305 km (0.05 R)
- M57: 43,050,078 km (0.097 R)
- M58: 44,089,036 km (0.114 R)
- M59: 46,935,135 km (0.066 R)
- M60: 47,148,312 km (0.081 R)
- M61: 47,468,601 km (0.1 R)
- M62: 47,575,564 km (0.088 R)
- M63: 48,865,247 km (0.098 R)
- M64: 51,259,262 km (0.105 R)
- M65: 51,588,676 km (0.117 R)
- M66: 51,698,631 km (0.054 R)
- M67: 52,470,556 km (0.114 R)
- M68: 53,914,175 km (0.114 R)
- M69: 56,954,004 km (0.092 R)
- M70: 57,865,354 km (0.093 R)
- M71: 59,356,396 km (0.075 R)
- M72: 60,280,312 km (0.075 R)
- M73: 60,396,101 km (0.097 R)
- M74: 60,512,040 km (0.116 R)
- M75: 61,791,849 km (0.042 R)
- M76: 62,259,343 km (0.081 R)
- M77: 62,610,898 km (0.042 R)
- M78: 63,315,653 km (0.056 R)
- M79: 64,259,616 km (0.081 R)
- M80: 65,684,236 km (0.092 R)
- M81: 66,042,074 km (0.04 R)
- M82: 66,400,361 km (0.066 R)
- M83: 73,332,128 km (0.089 R)
- M84: 73,703,281 km (0.057 R)
- M85: 74,075,031 km (0.109 R)
- M86: 74,820,328 km (0.101 R)
- M87: 75,318,638 km (0.108 R)
- M88: 75,943,209 km (0.059 R)
- M89: 79,344,766 km (0.033 R)
- M90: 80,489,638 km (0.11 R)
- M91: 81,383,934 km (0.113 R)
- M92: 82,924,493 km (0.053 R)
- M93: 83,053,297 km (0.06 R)
- M94: 83,311,204 km (0.12 R)
- M95: 86,817,927 km (0.096 R)
Planet 9 - Ice Giant
Semi-Major Axis: 17.45 AU
Status: Outer (Cold)
Composition: Methane/Ammonia Ices
Physical Data
Mass: 509.1
Radius: 6.2
Gravity: 13.24 G
Time & Orbit
Eccentricity (e): 0.038
Orbit Range: 16.79 AU - 18.11 AU
Year: 27461 Days
Day: 16.5 Hours
Environment
Temp: -204 °C
Axial Tilt: 27.4 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (94)
Outer Limit: 85,143,325 km
- M1: 79,736 km (0.106 R)
- M2: 282,590 km (0.115 R)
- M3: 658,081 km (0.039 R)
- M4: 783,294 km (0.055 R)
- M5: 1,618,948 km (0.089 R)
- M6: 2,528,653 km (0.092 R)
- M7: 4,156,726 km (0.117 R)
- M8: 4,533,115 km (0.102 R)
- M9: 5,217,974 km (0.052 R)
- M10: 5,419,632 km (0.055 R)
- M11: 6,039,565 km (0.087 R)
- M12: 6,198,139 km (0.075 R)
- M13: 7,177,855 km (0.068 R)
- M14: 7,972,819 km (0.102 R)
- M15: 8,204,994 km (0.101 R)
- M16: 8,676,078 km (0.057 R)
- M17: 8,795,308 km (0.044 R)
- M18: 8,914,986 km (0.061 R)
- M19: 9,035,113 km (0.091 R)
- M20: 9,706,059 km (0.071 R)
- M21: 11,681,649 km (0.06 R)
- M22: 12,211,076 km (0.087 R)
- M23: 13,430,598 km (0.066 R)
- M24: 14,265,055 km (0.099 R)
- M25: 14,547,047 km (0.094 R)
- M26: 16,645,007 km (0.074 R)
- M27: 17,240,107 km (0.096 R)
- M28: 17,691,145 km (0.095 R)
- M29: 17,993,931 km (0.105 R)
- M30: 18,681,632 km (0.085 R)
- M31: 19,611,682 km (0.108 R)
- M32: 20,636,278 km (0.113 R)
- M33: 21,355,694 km (0.081 R)
- M34: 21,436,178 km (0.077 R)
- M35: 21,516,662 km (0.096 R)
- M36: 23,479,835 km (0.111 R)
- M37: 24,146,892 km (0.1 R)
- M38: 24,820,232 km (0.111 R)
- M39: 26,185,162 km (0.079 R)
- M40: 26,616,603 km (0.061 R)
- M41: 26,876,753 km (0.083 R)
- M42: 30,695,538 km (0.095 R)
- M43: 30,877,300 km (0.095 R)
- M44: 30,968,255 km (0.102 R)
- M45: 31,059,360 km (0.088 R)
- M46: 32,343,808 km (0.107 R)
- M47: 33,271,763 km (0.08 R)
- M48: 33,365,112 km (0.062 R)
- M49: 34,208,545 km (0.11 R)
- M50: 34,491,285 km (0.075 R)
- M51: 35,154,004 km (0.093 R)
- M52: 35,439,287 km (0.109 R)
- M53: 35,916,504 km (0.101 R)
- M54: 36,588,198 km (0.061 R)
- M55: 38,334,454 km (0.104 R)
- M56: 38,530,128 km (0.107 R)
- M57: 38,628,115 km (0.07 R)
- M58: 39,513,585 km (0.116 R)
- M59: 40,505,119 km (0.098 R)
- M60: 40,804,315 km (0.114 R)
- M61: 42,614,150 km (0.102 R)
- M62: 46,624,570 km (0.11 R)
- M63: 47,567,037 km (0.114 R)
- M64: 47,672,204 km (0.036 R)
- M65: 48,410,021 km (0.113 R)
- M66: 48,727,467 km (0.07 R)
- M67: 49,257,941 km (0.09 R)
- M68: 52,916,058 km (0.119 R)
- M69: 53,461,342 km (0.102 R)
- M70: 54,118,227 km (0.094 R)
- M71: 54,227,882 km (0.119 R)
- M72: 58,002,386 km (0.068 R)
- M73: 59,467,846 km (0.097 R)
- M74: 61,746,222 km (0.087 R)
- M75: 64,517,522 km (0.117 R)
- M76: 65,216,743 km (0.086 R)
- M77: 65,567,251 km (0.052 R)
- M78: 65,801,371 km (0.117 R)
- M79: 66,505,080 km (0.071 R)
- M80: 67,565,430 km (0.067 R)
- M81: 67,920,126 km (0.117 R)
- M82: 68,275,421 km (0.093 R)
- M83: 68,512,534 km (0.106 R)
- M84: 69,464,126 km (0.099 R)
- M85: 70,659,861 km (0.12 R)
- M86: 72,586,832 km (0.109 R)
- M87: 76,123,624 km (0.08 R)
- M88: 77,232,594 km (0.073 R)
- M89: 77,479,729 km (0.089 R)
- M90: 78,098,765 km (0.068 R)
- M91: 79,715,918 km (0.097 R)
- M92: 80,340,938 km (0.086 R)
- M93: 83,997,559 km (0.097 R)
- M94: 84,124,567 km (0.045 R)
Kuiper Belt
Range: 30 - 47 AU
Composition
Type: Dwarf Planets/TNOs (Ices)
Reservoir of dwarf planets and volatile ices.
Outer System
Oort Cloud
Range: 494 - 11,521 AU
Composition
Type: Cometary Reservoir
System's final boundary, containing trillions of icy planetesimals.