Marx posted a helpful thread about the rarity of various Earthlike worlds. Going on that topic, and because of the repeat questions I see of "what is really rare or unusual?", presented here is a list of things that are unusual or rare. These are rare enough that the Galactic Mapping Project would consider entry as a Point of Interest. Where possible, I have included statistics on how rare they are or how many are known.
This isn't a list of everything that is interesting! It's a list of rarity, which is one of many entry points to "interesting". Particularly if you're trying to earn that one EDSM badge!
In almost all cases below "orbiting" means "directly orbiting", not "in the same system as" (for multiple-star systems), but I've sometimes used "directly" to try to clarify.
My general upper limit on these things are "20 known", with some exceptions for other things that are rare to start with. Finding more than 1 of a thing in a system would immediately make it significantly more rare. As usual thanks to both EDSM for cataloging the data and EDastro for providing selective dumps of that database to work with.
I will be adding more body types/info. These stats take a while to generate.
As of 12/21/2019 bodies listed: Earth-like worlds, Water worlds, Ammonia worlds, Combo systems of ELW/AW/WW, Water giants, Helium-rich gas giants, Stars with rings, class V gas giants
Earthlike worlds: See marx's thread.
Water worlds:
Ammonia worlds:
Less rare AW than you might expect:
Combo systems:
Water giants:
Less rare WG than you might expect:
Helium-Rich Gas Giants:
Less rare HRGG than you might expect:
Stars with Rings [excluding T-Tauri and brown dwarves]:
Note: Due to how the logs show very close asteroid belts as "rings" in ED logs, these numbers may have some inaccuracy.
Less rare ringed stars than you might expect:
O-class star records (where the O-class is by itself)
Class V Gas Giants (total: 54312)
This isn't a list of everything that is interesting! It's a list of rarity, which is one of many entry points to "interesting". Particularly if you're trying to earn that one EDSM badge!
In almost all cases below "orbiting" means "directly orbiting", not "in the same system as" (for multiple-star systems), but I've sometimes used "directly" to try to clarify.
My general upper limit on these things are "20 known", with some exceptions for other things that are rare to start with. Finding more than 1 of a thing in a system would immediately make it significantly more rare. As usual thanks to both EDSM for cataloging the data and EDastro for providing selective dumps of that database to work with.
I will be adding more body types/info. These stats take a while to generate.
As of 12/21/2019 bodies listed: Earth-like worlds, Water worlds, Ammonia worlds, Combo systems of ELW/AW/WW, Water giants, Helium-rich gas giants, Stars with rings, class V gas giants
Earthlike worlds: See marx's thread.
- 4 Earth like worlds in a system (12 known; only 2 are procedurally generated systems)
- More than 4 earth-like worlds (none known)
Water worlds:
- 8 water worlds in a system (2 known)
- More than 8 water worlds in a system (none known)
- WW orbiting class-O star (4 known)
- WW orbiting class-A super giant (11, all hand placed)
- WW orbiting Class-B super giant (none known)
- WW orbiting C star (12, all hand-placed)
- WW orbiting class-F super giant (8, all hand-placed)
- WW orbiting class-G super giant (4, all hand-placed)
- WW orbiting class-M super giant [not regular giants!] (2, 1 hand placed)
- WW orbiting class I giant (7 known)
- WW orbiting class V giant (none known)
- WW orbiting gas giant with ammonia-life (2, 1 hand placed)
- WW orbiting Icy Body (14 known)
- WW orbiting Rocky Icy Body (19 known)
- WW orbiting Water Giant (20 known)
- WW orbiting any WR star (15 known)
- WW orbiting AW (2 known)
- WW orbiting a metal-rich body (1 known)
- WW larger than 28,500 km (3 known)
- WW heavier than 350 earth-masses (5 known)
- WW with a surface temp > 900K (1 known)
- WW with rotational period < 0.1 days [super fast rotation] (6 known)
- WW orbiting CJ star (45 known)
- WW orbiting HRGG (44 known)
- WW orbiting ELW (56 known)
- WW orbiting gas giant with water-life (91 known)
- WW orbiting black hole (153 known)
- WW orbiting an MS-type star (at least 165 known)
- WW orbiting gas giant with water-life (166 known)
- WW orbiting an WD-type star (317 known)
- WW orbiting CN star (382 known)
- WW orbiting class-K giant (558 known)
- WW orbiting a WW (6500+ known)
- WW orbiting class II, III, IV giants (at least 8000)
- WW orbiting HMCs (more than 20,000)
Ammonia worlds:
- 4 ammonia worlds in a system (6 known)
- More than 4 ammonia worlds in a system (none known)
- Massing more than 800 earth-mass (2 known)
- AW orbiting a class V giant (none known)
- AW orbiting a CN star (2 known)
- AW orbiting a WR-N star (1 known)
- AW orbiting a WR-NC star (1 known)
- AW orbiting a WR-O star (1 known)
- AW orbiting any other WR type (none known)
- AW orbiting a MS star (7 known)
- AW orbiting a S star (5 known)
- AW orbiting a Gas giant with ammonia-life (double ammonia!) (14 known)
- AW orbiting a Helium-rich gas giant (25 known) [bonus: greater than 1 earth mass, none known]
- AW orbiting an icy body (23 known)
- AW orbiting a K-class giant (18 known, and they're ALL hand-placed systems)
Less rare AW than you might expect:
- AW around a Water giant (96 known)
- AW moon of another AW (72 known)
- AW around a black hole (48 known)
- AW of any class I to class IV giant (886 known)
- AW orbiting a giant with water-life (86 known)
- AW orbiting a WW (98 known)
- AW orbiting any white-dwarf type (47 known)
Combo systems:
- 2 or more of EACH TYPE: ELW, WW, AW (none)
- 5 or more WW and at least 1 ELW and 1 AW (4 known)
- 3 or more AW and at least 1 ELW and 1 WW (6 known)
- 3 or more ELW and 3 or more WW (7 known)
Water giants:
- 5 in a system (5 known)
- 4 in a system (17 known)
- In a "B" mass class system (34 known)
- In an "A" mass class system (none known)
- WG orbiting a B-class star directly (8 known; only 1 is procedurally generated)
- WG orbiting a K-class giant star directly (16 known, 9 hand-placed)
- WG orbiting an M-class giant star (none known)
- WG orbiting any WR type star (1 known)
- WG orbiting any white-dwarf star (5 known)
- WG orbiting any white-dwarf type directly (none known)
- WG orbiting an S-type star (2 known)
- WG orbiting an S-type star directly (none known)
- WG orbiting an M-class giant star (2 known)
- WG orbiting an M-class giant star directly (none known)
- WG massing more than 1000 earth-masses (5 known)
- WG massing less than 17 earth-masses (11 known)
- WG larger than 30,500 km (8 known)
- WG smaller than 16,000 km (4 known)
Less rare WG than you might expect:
- WG orbiting a black hole (87 known)
- WG orbiting a T-Tauri (512 known)
- WG orbiting a Herbig (1380+ known)
Helium-Rich Gas Giants:
- 17 or more HRGG (3 known) [Record: 23 HRGG]
- 16 HRGG (3 known)
- HRGG orbiting an A-class super-giant (17 systems known, mostly hand-placed)
- HRGG orbiting a B-class super-giant (2 systems known, 1 hand-placed)
- HRGG orbiting a F-class super-giant (4 systems known, all hand-placed)
- HRGG orbiting a G-class super-giant (2 systems known, all hand-placed)
- HRGG orbiting a gas giant with ammonia-life (1 known)
- HRGG orbiting a gas giant with water-life (10 known)
- HRGG orbing a black hole (7 known)
- HRGG orbiting a C-class star (3 systems known, all hand-placed)
- HRGG orbiting a class I or class II giant (3 known)
- HRGG orbiting a HMC world (3 known)
- HRGG orbiting an icy body (8 known)
- HRGG orbiting M-class giant star (13 systems, 9 hand-placed)
- HRGG orbiting MS-class star (2 systems known)
- HRGG orbiting an O-type star (41 known in 19 systems, some hand-placed)
- HRGG orbiting S-class star (1 systems known, hand-placed)
- HRGG orbiting a water giant (3 known)
- HRGG orbiting a water world (1 known)
- HRGG orbiting any WD-type (1 known)
- HRGG orbiting any WR-type (5 systems, all hand-placed)
Less rare HRGG than you might expect:
- HRGG orbiting another HRGG (330+ known)
- HRGG orbiting a K-class giant star (171 known in a dozen+ systems)
- HRGG orbiting a neutron star (150+ known)
Stars with Rings [excluding T-Tauri and brown dwarves]:
Note: Due to how the logs show very close asteroid belts as "rings" in ED logs, these numbers may have some inaccuracy.
- Ringed F-class star (1 known)
- Ringed G-class star (5 known)
- Ringed M-class giant star (2 known)
- Any ringed star with greater than 1 solar mass (24 known, 2 hand-placed)
Less rare ringed stars than you might expect:
- Ringed K-class star (58 known)
- Ringed M-class star (700+ known)
- Ringed Neutron star (200+ known)
- Ringed any white-dwarf (168 known)
O-class star records (where the O-class is by itself)
- Any ELW (none known)
- Any AW (none known)
- Any WW (2 known)
- Any WG (2 known, 1 is hand-placed)
- More to come....
Class V Gas Giants (total: 54312)
- 10 or more class V gas giants (1)
- 9 or more class V gas giants (4)
- Class V in a mass code "A" system (none)
- Class V orbiting C star (1, hand placed)
- Class V orbiting Y dwarf ( 7, 1 is hand placed)
- Class V orbiting CN star (11)
- Class V orbiting black hole (27)
- Class V orbiting MS star (40)
- Class V orbiting S star (40)
- Class V orbiting red super-giant (41, many hand placed)
- Class V orbiting class-B super giant (53)
- Class V orbiting red giant (53)
- Class V radius exceeds 77800 km (4)
- Class V radius less than 21100 km (2)
- Class V mass exceeds 4000 earth-mass (16, all hand placed)
- Class V mass less than 33 earth-mass (2)
- Class V temperature greater than 11100 K (4)
- Class V temperature is an impossible 0 K (many)
- This is likely to be bad data
- If you disregard the 0 K entries, the lowest temperature is 1400 K
- Class V rotational period between -0.1 and 0.1 [fast spinning] (28)
- Class V orbital period less than 0.011 days [16 minutes!] (6)
- Class V orbital period more than 800 days (2)
- Class V gravity more than 400 (2, hand placed)
- Class V gravity less than 0.60 (2)
- Class V orbiting any white dwarf (83)
- Class V orbiting class-T star (86)
- Class V orbiting any wolf-rayet (118)
- Class V orbiting Herbig (147)
- Class V orbiting class-G super giant (174)
- Class V orbiting class-K super giant (210)
- Class V orbiting class-F super giant (336)
- Class V orbiting class L star (426)
- Class V orbiting class-A super giant (1000+)
- class V orbiting anything else (exceeds 1000, or does not exist)
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