G4V Star System Generated (Seed: 1768537716)
Star Details
Spectral Class: G9V
Temperature: 5,240 K
Mass: 0.91 sol
Luminosity: 0.72 lux
Habitable Zone (HZ)
Inner Boundary: 0.81 AU
Outer Boundary: 1.17 AU
Physical Limits
Snow Line: 4.07 AU
Max System Radius: 19.1 AU
Planetary System (8 Planets)
Planet 1 - Terrestrial
Semi-Major Axis: 0.84 AU
Status: HZ
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 0.33
Radius: 0.64
Gravity: 0.81 G
Time & Orbit
Eccentricity (e): 0.238
Orbit Range: 0.64 AU - 1.04 AU
Year: 295 Days
Day: 30.9 Hours
Environment
Temp: 20 °C
Axial Tilt: 14.6 °
Atmosphere: Nâ‚‚, Oâ‚‚
Biome: Arid/Tundra
Planet 2 - Terrestrial
Semi-Major Axis: 1.22 AU
Status: Outer (Cold)
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 2.62
Radius: 1.47
Gravity: 1.21 G
Time & Orbit
Eccentricity (e): 0.19
Orbit Range: 0.99 AU - 1.45 AU
Year: 516 Days
Day: 23 Hours
Environment
Temp: -32 °C
Axial Tilt: 27.8 °
Atmosphere: Thin Nâ‚‚/CHâ‚„
Biome: Ice Cap/Desert
Satellites (1)
Outer Limit: 102,697,649 km
- M1: 168,298 km (0.058 R)
Planet 3 - Terrestrial
Semi-Major Axis: 3.41 AU
Status: Outer (Cold)
Composition: Rocky (Silicates/Metals)
Physical Data
Mass: 0.31
Radius: 0.63
Gravity: 0.78 G
Time & Orbit
Eccentricity (e): 0.241
Orbit Range: 2.59 AU - 4.23 AU
Year: 2411 Days
Day: 39.4 Hours
Environment
Temp: -124 °C
Axial Tilt: 38.9 °
Atmosphere: Thin Nâ‚‚/CHâ‚„
Biome: Ice Cap/Desert
Planet 4 - Gas Giant
Semi-Major Axis: 4.08 AU
Status: Outer (Cold)
Composition: Hydrogen/Helium Atmosphere
Physical Data
Mass: 122
Radius: 14.9
Gravity: 0.55 G
Time & Orbit
Eccentricity (e): 0.178
Orbit Range: 3.35 AU - 4.81 AU
Year: 3155 Days
Day: 6.1 Hours
Environment
Temp: -142 °C
Axial Tilt: 34.7 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (50)
Outer Limit: 102,697,649 km
- M1: 192,532 km (0.113 R)
- M2: 366,216 km (0.095 R)
- M3: 479,760 km (0.066 R)
- M4: 634,594 km (0.074 R)
- M5: 742,604 km (0.086 R)
- M6: 929,452 km (0.087 R)
- M7: 1,173,147 km (0.1 R)
- M8: 1,311,525 km (0.11 R)
- M9: 1,412,952 km (0.105 R)
- M10: 1,836,763 km (0.082 R)
- M11: 1,980,526 km (0.075 R)
- M12: 2,098,409 km (0.108 R)
- M13: 2,362,450 km (0.082 R)
- M14: 2,594,326 km (0.11 R)
- M15: 2,800,921 km (0.068 R)
- M16: 2,911,923 km (0.117 R)
- M17: 3,621,316 km (0.114 R)
- M18: 3,791,708 km (0.058 R)
- M19: 3,914,976 km (0.077 R)
- M20: 4,178,568 km (0.04 R)
- M21: 4,460,859 km (0.103 R)
- M22: 4,565,278 km (0.113 R)
- M23: 4,749,732 km (0.031 R)
- M24: 4,909,802 km (0.096 R)
- M25: 5,099,043 km (0.053 R)
- M26: 5,373,406 km (0.071 R)
- M27: 5,624,730 km (0.087 R)
- M28: 5,737,677 km (0.109 R)
- M29: 5,980,175 km (0.094 R)
- M30: 6,081,004 km (0.073 R)
- M31: 6,328,439 km (0.053 R)
- M32: 6,623,745 km (0.119 R)
- M33: 6,818,073 km (0.034 R)
- M34: 7,105,749 km (0.062 R)
- M35: 7,243,379 km (0.09 R)
- M36: 7,568,007 km (0.049 R)
- M37: 7,708,629 km (0.098 R)
- M38: 8,135,731 km (0.113 R)
- M39: 8,619,381 km (0.077 R)
- M40: 8,996,666 km (0.119 R)
- M41: 9,212,386 km (0.112 R)
- M42: 9,903,678 km (0.064 R)
- M43: 10,092,172 km (0.107 R)
- M44: 10,752,048 km (0.092 R)
- M45: 10,945,777 km (0.088 R)
- M46: 11,229,564 km (0.095 R)
- M47: 11,425,986 km (0.053 R)
- M48: 11,913,226 km (0.036 R)
- M49: 12,296,945 km (0.062 R)
- M50: 12,462,699 km (0.112 R)
Planet 5 - Gas Giant
Semi-Major Axis: 5.22 AU
Status: Outer (Cold)
Composition: Hydrogen/Helium Atmosphere
Physical Data
Mass: 761.9
Radius: 11.7
Gravity: 5.57 G
Time & Orbit
Eccentricity (e): 0.159
Orbit Range: 4.39 AU - 6.05 AU
Year: 4566 Days
Day: 13.7 Hours
Environment
Temp: -142 °C
Axial Tilt: 20.4 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (78)
Outer Limit: 102,697,649 km
- M1: 210,484 km (0.115 R)
- M2: 492,925 km (0.113 R)
- M3: 642,373 km (0.117 R)
- M4: 871,707 km (0.09 R)
- M5: 1,258,716 km (0.038 R)
- M6: 1,471,744 km (0.081 R)
- M7: 1,631,514 km (0.065 R)
- M8: 2,688,274 km (0.089 R)
- M9: 2,925,386 km (0.07 R)
- M10: 3,210,670 km (0.068 R)
- M11: 3,742,789 km (0.112 R)
- M12: 4,052,906 km (0.116 R)
- M13: 4,302,584 km (0.063 R)
- M14: 4,394,587 km (0.099 R)
- M15: 4,533,863 km (0.102 R)
- M16: 4,745,693 km (0.047 R)
- M17: 4,888,709 km (0.104 R)
- M18: 5,033,071 km (0.115 R)
- M19: 5,499,966 km (0.097 R)
- M20: 5,980,923 km (0.114 R)
- M21: 6,422,685 km (0.091 R)
- M22: 6,607,588 km (0.064 R)
- M23: 6,821,214 km (0.117 R)
- M24: 7,754,555 km (0.078 R)
- M25: 8,178,964 km (0.068 R)
- M26: 8,698,368 km (0.084 R)
- M27: 8,844,675 km (0.067 R)
- M28: 9,050,671 km (0.095 R)
- M29: 9,139,532 km (0.107 R)
- M30: 9,228,543 km (0.084 R)
- M31: 9,347,773 km (0.117 R)
- M32: 9,557,808 km (0.105 R)
- M33: 9,708,752 km (0.057 R)
- M34: 10,104,738 km (0.099 R)
- M35: 10,755,937 km (0.099 R)
- M36: 10,912,865 km (0.081 R)
- M37: 11,007,561 km (0.112 R)
- M38: 11,292,844 km (0.119 R)
- M39: 11,612,984 km (0.109 R)
- M40: 11,741,787 km (0.086 R)
- M41: 11,903,503 km (0.073 R)
- M42: 12,065,966 km (0.092 R)
- M43: 12,426,048 km (0.112 R)
- M44: 12,989,434 km (0.088 R)
- M45: 13,291,172 km (0.064 R)
- M46: 13,459,769 km (0.077 R)
- M47: 13,901,382 km (0.069 R)
- M48: 15,360,859 km (0.08 R)
- M49: 15,537,983 km (0.03 R)
- M50: 15,786,914 km (0.118 R)
- M51: 16,577,838 km (0.115 R)
- M52: 17,087,817 km (0.1 R)
- M53: 18,423,127 km (0.102 R)
- M54: 18,573,473 km (0.096 R)
- M55: 18,648,871 km (0.104 R)
- M56: 18,951,357 km (0.107 R)
- M57: 19,217,492 km (0.068 R)
- M58: 19,599,715 km (0.105 R)
- M59: 19,753,202 km (0.074 R)
- M60: 19,830,245 km (0.045 R)
- M61: 20,332,744 km (0.06 R)
- M62: 20,410,385 km (0.108 R)
- M63: 20,566,117 km (0.074 R)
- M64: 20,878,627 km (0.087 R)
- M65: 21,271,620 km (0.09 R)
- M66: 21,985,053 km (0.064 R)
- M67: 22,304,594 km (0.091 R)
- M68: 23,150,869 km (0.072 R)
- M69: 24,130,885 km (0.091 R)
- M70: 24,295,592 km (0.073 R)
- M71: 24,626,053 km (0.025 R)
- M72: 25,082,776 km (0.118 R)
- M73: 25,207,840 km (0.078 R)
- M74: 25,333,203 km (0.025 R)
- M75: 28,358,072 km (0.071 R)
- M76: 28,924,150 km (0.111 R)
- M77: 29,186,694 km (0.099 R)
- M78: 29,406,154 km (0.108 R)
Planet 6 - Ice Giant
Semi-Major Axis: 11.77 AU
Status: Outer (Cold)
Composition: Methane/Ammonia Ices
Physical Data
Mass: 641
Radius: 3.4
Gravity: 55.45 G
Time & Orbit
Eccentricity (e): 0.092
Orbit Range: 10.69 AU - 12.85 AU
Year: 15461 Days
Day: 24.7 Hours
Environment
Temp: -189 °C
Axial Tilt: 21.1 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (85)
Outer Limit: 102,697,649 km
- M1: 52,509 km (0.119 R)
- M2: 169,046 km (0.069 R)
- M3: 384,167 km (0.108 R)
- M4: 940,073 km (0.091 R)
- M5: 962,961 km (0.089 R)
- M6: 1,104,481 km (0.094 R)
- M7: 1,252,583 km (0.104 R)
- M8: 1,380,788 km (0.092 R)
- M9: 1,406,968 km (0.088 R)
- M10: 2,083,001 km (0.112 R)
- M11: 2,390,424 km (0.1 R)
- M12: 2,911,025 km (0.102 R)
- M13: 3,184,191 km (0.088 R)
- M14: 4,866,269 km (0.119 R)
- M15: 5,067,478 km (0.041 R)
- M16: 6,200,533 km (0.104 R)
- M17: 6,374,814 km (0.116 R)
- M18: 6,907,233 km (0.039 R)
- M19: 7,500,089 km (0.089 R)
- M20: 7,592,690 km (0.087 R)
- M21: 8,108,953 km (0.042 R)
- M22: 8,977,967 km (0.111 R)
- M23: 9,373,653 km (0.098 R)
- M24: 9,977,729 km (0.068 R)
- M25: 10,181,930 km (0.064 R)
- M26: 10,233,093 km (0.096 R)
- M27: 11,435,411 km (0.104 R)
- M28: 12,188,786 km (0.092 R)
- M29: 12,958,168 km (0.075 R)
- M30: 13,236,719 km (0.115 R)
- M31: 14,198,484 km (0.114 R)
- M32: 14,485,562 km (0.102 R)
- M33: 15,065,702 km (0.096 R)
- M34: 15,182,538 km (0.098 R)
- M35: 15,358,465 km (0.07 R)
- M36: 15,417,257 km (0.101 R)
- M37: 16,068,906 km (0.097 R)
- M38: 16,669,092 km (0.109 R)
- M39: 16,911,291 km (0.028 R)
- M40: 17,154,537 km (0.116 R)
- M41: 17,399,130 km (0.059 R)
- M42: 18,201,423 km (0.114 R)
- M43: 19,332,383 km (0.102 R)
- M44: 20,615,185 km (0.098 R)
- M45: 21,005,486 km (0.116 R)
- M46: 21,266,983 km (0.082 R)
- M47: 24,693,971 km (0.117 R)
- M48: 26,154,046 km (0.06 R)
- M49: 26,505,900 km (0.063 R)
- M50: 28,287,910 km (0.08 R)
- M51: 28,576,634 km (0.052 R)
- M52: 29,667,951 km (0.05 R)
- M53: 30,108,367 km (0.082 R)
- M54: 30,624,779 km (0.084 R)
- M55: 31,218,682 km (0.092 R)
- M56: 32,191,667 km (0.046 R)
- M57: 33,098,678 km (0.115 R)
- M58: 34,397,936 km (0.114 R)
- M59: 34,551,872 km (0.106 R)
- M60: 35,324,994 km (0.074 R)
- M61: 35,635,858 km (0.085 R)
- M62: 36,338,669 km (0.075 R)
- M63: 36,652,376 km (0.06 R)
- M64: 37,757,755 km (0.087 R)
- M65: 39,920,341 km (0.096 R)
- M66: 41,302,327 km (0.085 R)
- M67: 42,369,707 km (0.088 R)
- M68: 42,782,597 km (0.045 R)
- M69: 43,113,957 km (0.053 R)
- M70: 44,112,971 km (0.044 R)
- M71: 46,388,654 km (0.075 R)
- M72: 48,012,689 km (0.076 R)
- M73: 49,308,057 km (0.074 R)
- M74: 50,003,537 km (0.104 R)
- M75: 50,789,823 km (0.045 R)
- M76: 52,197,839 km (0.111 R)
- M77: 52,374,813 km (0.056 R)
- M78: 52,640,499 km (0.06 R)
- M79: 53,797,040 km (0.076 R)
- M80: 56,407,224 km (0.111 R)
- M81: 56,498,029 km (0.056 R)
- M82: 58,874,242 km (0.084 R)
- M83: 59,889,413 km (0.092 R)
- M84: 60,724,319 km (0.113 R)
- M85: 62,030,607 km (0.038 R)
Planet 7 - Ice Giant
Semi-Major Axis: 13.81 AU
Status: Outer (Cold)
Composition: Methane/Ammonia Ices
Physical Data
Mass: 856.2
Radius: 4.6
Gravity: 40.46 G
Time & Orbit
Eccentricity (e): 0.056
Orbit Range: 13.04 AU - 14.58 AU
Year: 19650 Days
Day: 21.8 Hours
Environment
Temp: -197 °C
Axial Tilt: 48.1 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (93)
Outer Limit: 102,697,649 km
- M1: 59,839 km (0.085 R)
- M2: 205,847 km (0.111 R)
- M3: 236,664 km (0.117 R)
- M4: 396,584 km (0.091 R)
- M5: 520,601 km (0.092 R)
- M6: 610,060 km (0.06 R)
- M7: 962,214 km (0.113 R)
- M8: 1,492,538 km (0.049 R)
- M9: 2,098,709 km (0.098 R)
- M10: 2,390,125 km (0.061 R)
- M11: 3,764,032 km (0.092 R)
- M12: 4,480,456 km (0.118 R)
- M13: 4,665,958 km (0.068 R)
- M14: 4,759,755 km (0.11 R)
- M15: 4,854,152 km (0.097 R)
- M16: 6,084,893 km (0.103 R)
- M17: 6,187,368 km (0.068 R)
- M18: 7,570,400 km (0.094 R)
- M19: 7,736,005 km (0.105 R)
- M20: 8,524,087 km (0.107 R)
- M21: 8,638,828 km (0.081 R)
- M22: 8,985,895 km (0.091 R)
- M23: 9,044,238 km (0.118 R)
- M24: 9,102,582 km (0.089 R)
- M25: 9,278,658 km (0.113 R)
- M26: 9,455,782 km (0.042 R)
- M27: 10,603,347 km (0.12 R)
- M28: 11,413,570 km (0.036 R)
- M29: 12,502,792 km (0.106 R)
- M30: 13,291,472 km (0.11 R)
- M31: 15,892,979 km (0.118 R)
- M32: 16,890,048 km (0.108 R)
- M33: 18,869,079 km (0.036 R)
- M34: 21,697,675 km (0.088 R)
- M35: 22,881,443 km (0.115 R)
- M36: 23,441,089 km (0.108 R)
- M37: 24,329,551 km (0.1 R)
- M38: 26,139,236 km (0.12 R)
- M39: 26,640,239 km (0.12 R)
- M40: 26,892,012 km (0.117 R)
- M41: 28,761,836 km (0.104 R)
- M42: 30,322,591 km (0.088 R)
- M43: 30,673,099 km (0.117 R)
- M44: 31,644,138 km (0.09 R)
- M45: 35,627,481 km (0.097 R)
- M46: 36,740,938 km (0.029 R)
- M47: 37,020,985 km (0.104 R)
- M48: 38,054,258 km (0.101 R)
- M49: 38,243,200 km (0.1 R)
- M50: 38,811,672 km (0.117 R)
- M51: 39,669,765 km (0.095 R)
- M52: 39,861,250 km (0.047 R)
- M53: 39,957,142 km (0.114 R)
- M54: 40,149,077 km (0.086 R)
- M55: 40,630,333 km (0.064 R)
- M56: 41,404,352 km (0.119 R)
- M57: 42,868,766 km (0.115 R)
- M58: 44,350,084 km (0.07 R)
- M59: 45,346,855 km (0.067 R)
- M60: 46,552,763 km (0.113 R)
- M61: 51,167,857 km (0.05 R)
- M62: 52,738,336 km (0.052 R)
- M63: 54,112,093 km (0.025 R)
- M64: 56,356,061 km (0.073 R)
- M65: 56,571,332 km (0.093 R)
- M66: 58,957,568 km (0.115 R)
- M67: 59,723,659 km (0.103 R)
- M68: 60,603,294 km (0.112 R)
- M69: 60,823,801 km (0.092 R)
- M70: 60,934,205 km (0.085 R)
- M71: 61,487,118 km (0.069 R)
- M72: 62,375,281 km (0.083 R)
- M73: 63,603,330 km (0.066 R)
- M74: 64,501,516 km (0.098 R)
- M75: 65,743,327 km (0.111 R)
- M76: 66,651,387 km (0.028 R)
- M77: 66,993,068 km (0.113 R)
- M78: 67,563,634 km (0.081 R)
- M79: 71,370,152 km (0.081 R)
- M80: 71,486,539 km (0.105 R)
- M81: 71,836,150 km (0.108 R)
- M82: 72,888,571 km (0.113 R)
- M83: 74,299,727 km (0.08 R)
- M84: 74,772,157 km (0.085 R)
- M85: 74,890,340 km (0.116 R)
- M86: 76,195,282 km (0.071 R)
- M87: 76,433,292 km (0.073 R)
- M88: 77,507,554 km (0.117 R)
- M89: 78,586,903 km (0.036 R)
- M90: 79,429,737 km (0.101 R)
- M91: 80,396,738 km (0.114 R)
- M92: 80,881,734 km (0.063 R)
- M93: 81,003,058 km (0.037 R)
Planet 8 - Ice Giant
Semi-Major Axis: 17.82 AU
Status: Outer (Cold)
Composition: Methane/Ammonia Ices
Physical Data
Mass: 812.1
Radius: 4.6
Gravity: 38.38 G
Time & Orbit
Eccentricity (e): 0.091
Orbit Range: 16.2 AU - 19.44 AU
Year: 28803 Days
Day: 17.4 Hours
Environment
Temp: -202 °C
Axial Tilt: 17.8 °
Atmosphere: Hâ‚‚, CHâ‚„
Biome: None
Satellites (95)
Outer Limit: 102,697,649 km
- M1: 60,438 km (0.046 R)
- M2: 93,499 km (0.05 R)
- M3: 590,612 km (0.105 R)
- M4: 817,552 km (0.088 R)
- M5: 940,671 km (0.034 R)
- M6: 1,136,645 km (0.078 R)
- M7: 1,309,580 km (0.028 R)
- M8: 1,345,184 km (0.08 R)
- M9: 2,423,336 km (0.045 R)
- M10: 4,757,661 km (0.082 R)
- M11: 4,923,864 km (0.031 R)
- M12: 5,376,398 km (0.074 R)
- M13: 5,665,870 km (0.118 R)
- M14: 6,811,789 km (0.089 R)
- M15: 7,571,298 km (0.11 R)
- M16: 8,423,856 km (0.074 R)
- M17: 8,963,605 km (0.116 R)
- M18: 9,653,850 km (0.034 R)
- M19: 10,005,405 km (0.059 R)
- M20: 11,974,711 km (0.051 R)
- M21: 13,507,940 km (0.111 R)
- M22: 13,586,329 km (0.066 R)
- M23: 13,664,718 km (0.068 R)
- M24: 13,743,257 km (0.118 R)
- M25: 14,297,517 km (0.12 R)
- M26: 14,778,474 km (0.099 R)
- M27: 15,838,525 km (0.1 R)
- M28: 16,086,558 km (0.086 R)
- M29: 16,335,938 km (0.058 R)
- M30: 16,502,889 km (0.067 R)
- M31: 16,838,437 km (0.045 R)
- M32: 18,550,136 km (0.069 R)
- M33: 18,811,633 km (0.081 R)
- M34: 19,780,728 km (0.042 R)
- M35: 21,128,306 km (0.118 R)
- M36: 21,675,535 km (0.106 R)
- M37: 22,227,551 km (0.066 R)
- M38: 22,784,055 km (0.104 R)
- M39: 23,345,197 km (0.093 R)
- M40: 23,439,144 km (0.116 R)
- M41: 23,721,884 km (0.04 R)
- M42: 25,055,848 km (0.089 R)
- M43: 25,441,362 km (0.046 R)
- M44: 28,696,312 km (0.094 R)
- M45: 29,403,461 km (0.093 R)
- M46: 30,014,120 km (0.1 R)
- M47: 30,834,814 km (0.112 R)
- M48: 31,144,482 km (0.097 R)
- M49: 32,184,187 km (0.094 R)
- M50: 32,288,756 km (0.119 R)
- M51: 36,020,026 km (0.106 R)
- M52: 37,550,113 km (0.104 R)
- M53: 38,434,087 km (0.092 R)
- M54: 39,324,792 km (0.111 R)
- M55: 41,353,639 km (0.066 R)
- M56: 42,955,084 km (0.095 R)
- M57: 47,760,167 km (0.111 R)
- M58: 49,198,401 km (0.108 R)
- M59: 49,560,129 km (0.107 R)
- M60: 50,772,470 km (0.097 R)
- M61: 51,749,344 km (0.12 R)
- M62: 52,240,025 km (0.109 R)
- M63: 52,979,039 km (0.036 R)
- M64: 54,467,388 km (0.053 R)
- M65: 55,592,663 km (0.102 R)
- M66: 56,347,085 km (0.044 R)
- M67: 57,866,102 km (0.077 R)
- M68: 58,120,568 km (0.081 R)
- M69: 58,375,483 km (0.098 R)
- M70: 58,630,697 km (0.101 R)
- M71: 59,398,583 km (0.104 R)
- M72: 59,783,797 km (0.079 R)
- M73: 61,982,138 km (0.12 R)
- M74: 62,112,288 km (0.063 R)
- M75: 62,895,134 km (0.078 R)
- M76: 64,866,235 km (0.032 R)
- M77: 65,130,575 km (0.118 R)
- M78: 65,527,757 km (0.095 R)
- M79: 65,792,994 km (0.103 R)
- M80: 67,659,676 km (0.065 R)
- M81: 71,444,801 km (0.063 R)
- M82: 73,500,725 km (0.112 R)
- M83: 76,132,600 km (0.076 R)
- M84: 76,830,325 km (0.095 R)
- M85: 76,970,199 km (0.081 R)
- M86: 79,218,505 km (0.082 R)
- M87: 84,211,185 km (0.109 R)
- M88: 86,381,850 km (0.1 R)
- M89: 90,926,035 km (0.05 R)
- M90: 94,946,627 km (0.107 R)
- M91: 95,396,917 km (0.114 R)
- M92: 95,998,450 km (0.104 R)
- M93: 96,601,179 km (0.062 R)
- M94: 96,752,124 km (0.094 R)
- M95: 98,720,832 km (0.085 R)
Kuiper Belt
Range: 30 - 53 AU
Composition
Type: Dwarf Planets/TNOs (Ices)
Reservoir of dwarf planets and volatile ices.
Outer System
Oort Cloud
Range: 267 - 11,662 AU
Composition
Type: Cometary Reservoir
System's final boundary, containing trillions of icy planetesimals.