Mass Codes and Star Types

[marx]

Prompted by a question from @LordFerret , I went through the EDSM data again to make an analysis of mass codes and star types, in a more thorough way than I did before. The data is from the EDSM dumps, and @Orvidius 's processed data dumps on EDAstro saved me quite a lot of work to be done there, so thanks for making and sharing those!
I looked at primary stars (when the star is the main star, visible on the galaxy map, and there are other stars in the system) and single stars, excluding secondaries. There are three categories: one with only primaries, one with only singles, and one with the two combined. Usually, there's barely any difference between the two: pretty much the only time there is a significant difference is with T and Y dwarfs, as there are very few systems where they are the primary stars and there are other stars present too.

Here's the data: https://docs.google.com/spreadsheets/d/1auRhEiIvl7o5bpCY-68tgAnGlpp44qSoSIDVL0WOOW8/edit?usp=sharing
Broken down into just main sequence (for easier visibility there), and into an extended version with the "exotic" stars as well.

Don't forget that this data would be affected by peoples' travel habits too! While all stars are auto-scanned since 2018. Dec., many people restrict their route plotter to scoopable stars only. It's likely that those are over-represented to some degree. (Then they might also be leaving out M, K, and so on.)


So, what is there to be found from this? Let's see...

First, most star types fall strongly into one mass code, with G stars being an interesting exception: they are split almost evenly between mass codes C and D. There are always some outliers though, and don't forget that the data includes giant stars as well. Also, the suppression corridor sometimes produces some weird stuff. (For example, mass code H, single T star.)
As an interesting bit, M dwarfs and T Tauri Stars are the only star types which appear across all mass codes, although this should be little wonder. In the case of M, this is only because of giant stars, too - if we were to move those into their own categories, then it'd be only TTS.

Second, if we look at things the other way, to see what types of stars the different mass codes are made up of, this is what we get:

Mass code A: T (35.81%), Y (30.12%), L (24.26%), M (6.79%), TTS (3.02%)
Mass code B: M (96.19%), TTS (1.79%), K (1.02%), L (0.99%)
Mass code C: K (73.69%), G (15.83%), M (9.45%), TTS (1.03%)
Mass code D: F (42.03%), A (20.34%), NS (15.5%), G (15.27%), K (3.11%), WD (1.62%), M (1.24%), C (0.35%), TTS (0.3%), L (0.23%)
Mass code E: B (49.31%), NS (30.45%), A (7.62%), BH (4.31%), TTS (4.19%), Ae/Be (2.86%), F (0.44%), G (0.43%), M (0.22%), K (0.16%), L (0.02%)
Mass code F: BH (53.33%), B (30.11%), O (6.05%), Ae/Be (4.96%), NS (2.55%), TTS (2.52%), A (0.48%)
Mass code G: O (50.03%), BH (33.79%), B (7.46%), Ae/Be (5.04%), TTS (2.94%), K (0.25%), M (0.16%), G (0.11%), WD (0.08%), A(0.07%), L (0.05%), C (0.01%)
Mass code H: BH (41.49%), WR (29.57%), O (10.68%), B (7.3%), A (5.41%), Ae/Be (3.98%), TTS (0.86%), K (0.21%), M (0.2%), G (0.14%), WD (0.08%), L (0.05%). F (0.04%), C (0.01%)

Do bear in mind that some star types can be seriously restricted in where they appear! So this isn't an "if I go to a mass code F systems, I have a 53% chance of coming across a black hole" thing. Still, it might be useful to know what seems to be possible, and also what seems to be more (or less) common.

 

[Anticon]

Great! Something else to aim for: filling in the blanks on that spreadsheet. Starting with an F code f... Thanks for your work, much appreciated.

 

[yLordMagnus]

Updated it to 09-2024 (Using 67.541.084 Stars)
Link: Google - Spreadsheet

Screenshot Table A (30/09/2024):

Screenshot Table B (30/09/2024):

 

[marx]

Hey, thanks! It's nice to see independent reproduction and verification, especially since my original post is four years old. Also, more details in some areas, though less in others. It looks to me that ratios didn't change substantially, except maybe on class G systems: if so, then it seems like more people are scanning those on mass code D now (most likely veterans preferring to explore that mass code). Hm, breaking down that data by time might be interesting.

However, there is one thing that jumped out to me in comparison: you list class O stars as mass code F only. I think there's an error there, as there are plenty of them in the higher mass codes too.

Oh, and yes, EDSM also counts systems which were submitted from the game logging them when plotting routes. I don't recall around when that was added to the journals, but there's quite a lot of those by today, so that's the reason for the EDSM system count disparity there. That was on 2020 May, but now I'm not sure if EDSM includes them in the count or not, so I don't know.

Update: something else that's quite weird: you seem to have slightly fewer stars in total than I did, back four years ago. 32.1 million then, 31.5 million now. We both filtered for proc. gen. stars, so how is that possible? Going by exploration activity, there should be far more than that. Did EDSM's auto-pruning remove that many systems and stars? If it did, then welp, another reason not to use it.

 

[yLordMagnus]

However, there is one thing that jumped out to me in comparison: you list class O stars as mass code F only. I think there's an error there, as there are plenty of them in the higher mass codes too.

Update: something else that's quite weird: you seem to have slightly fewer stars in total than I did, back four years ago. We both filtered for proc. gen. stars, so how is that possible? Did EDSM's auto-pruning remove that many systems and stars? If it did, then welp, another reason not to use it.

You are correct about the O class stars, I probaly forgot to add them to my tables, will do that when I get back home.

About the prunning, shouldn't be my case, downloaded from a mediafire folder that had the dumps piling up since 2020, and the first 2 additions to it were the dumps of all bodies since EDSM was created, I personally think I only removed 2-3 Million systems that weren't procgen or had incomplete data.

Was your original analysis in 2020 also for only the main star? for this data I'm only checking the first star of the systems, if it has a B star or a star as a Planet it wasn't accounted for on my tables, I have around 110.6 Million stars stored, 32.1 Million being main stars (So 32.1 Million systems), and 78.5 Miilion that are all the rest.

This reminds me that my tables only sum up to 31.523.763 of ~32.100.000 so I forgot to add around 600K stars... Guess I will have some work out for me when I get home

 

[marx]

You are correct about the O class stars, I probaly forgot to add them to my tables, will do that when I get back home.

About the prunning, shouldn't be my case, downloaded from a mediafire folder that had the dumps piling up since 2020, and the first 2 additions to it were the dumps of all bodies since EDSM was created, I personally think I only removed 2-3 Million systems that weren't procgen or had incomplete data.

Was your original analysis in 2020 also for only the main star? for this data I'm only checking the first star of the systems, if it has a B star or a star as a Planet it wasn't accounted for on my tables.

Sure, same here. I did make a separate breakdown of single-star systems only, but they are included in the totals of course.
I'd look through my earlier processed data to see if I might have made some errors there, but it was four years ago, I've deleted them since. Well, if you look through your stuff and find no errors there, I guess I'll take a look at other data sources and redo the original analysis.
For example, EDAstro today says "Database counts: 35,821,530 systems (85,173,791 visited, 50,647,739 route only); 118,338,658 stars; 368,538,565 planets;", and although the stars there will of course include all ones, not just the mains, the systems alone ought to make more.
Even so... that's not a lot of systems... hmm.

 

[yLordMagnus]

Sure, same here. I did make a separate breakdown of single-star systems only, but they are included in the totals of course.
I'd look through my earlier processed data to see if I might have made some errors there, but it was four years ago, I've deleted them since. Well, if you look through your stuff and find no errors there, I guess I'll take a look at other data sources and redo the original analysis.
For example, EDAstro today says "Database counts: 35,821,530 systems (85,173,791 visited, 50,647,739 route only); 118,338,658 stars; 368,538,565 planets;", and although the stars there will of course include all ones, not just the mains, the systems alone ought to make more.
Even so... that's not a lot of systems... hmm.

Fixed it, now it is also in a google Spreadsheet.

 

[marx]

Yep, good job on fixing the data, as well as on improving the presentation!
Now with the larger data set, and issues fixed, I noticed something interesting in this "four years later" scenario: it seems people have been focusing more than before on the outliers, the special cases. The numbers of those appear to have risen faster than the "normals" did. Might be due to squadrons, better guidance of veteran explorers, how there have been fewer new explorers coming in than before, people looking for exobio special cases... probably all of these.
Fun to see some new stuff too, like how there is now one Y main class star in a mass code C system.

So, again, thanks for doing this!