Codex glitches Red Giant discovery?

ChipStar65

ChipStar65
I recently crossed into the previously unvisited Elysian Shore region of the galaxy, and the Codex entries have been happening very frequently. One, however, did not:
This is the star --
Cl3oc81.jpg


This is the system --
gsMip8f.jpg


This is the relevant Codex page with the item selected that should read Confirmed --
lvb49d0.jpg


and this is the visual version of the same page --
czPZH0L.jpg


Is this kind of error common? So far for me the Codex has been very reliable.
 

ChipStar65

ChipStar65
I did see those numbers and thought it odd because red giants are more often huge, with a radius as large as Mars' orbit. But the SysMap and other sources clearly say "Red Giant," so I'm at a loss to explain this. It could be a misclassification to begin with, but how common is that?

Classification as far as I know is by main sequence spectral class (in this case a cooler M-type) and further by evolutionary status -- red giants are most often ancient stars that have had the time to finish burning hydrogen. If the star was very small when young, its "giant" stage could be comparatively small as well, but spectral class and age would still make it a giant compared to its earlier size.
 
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Sapyx

Sapyx
The Codex and the galaxy map seem to have different definitions of what qualifies as a "giant". I've noticed when surveying B-class stars that I found several "giants" in the Codex, even though they were not marked as "giants" on the galaxy/system map. I don't know if this is your problem, but it's a possibility.
 
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Deleted member 38366

D
Sapyx said:
The Codex and the galaxy map seem to have different definitions of what qualifies as a "giant". I've noticed when surveying B-class stars that I found several "giants" in the Codex, even though they were not marked as "giants" on the galaxy/system map. I don't know if this is your problem, but it's a possibility.
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^^^^ This pretty much

I've scanned plenty of so-called "Giants" as well (i.e. M, K) - yet the Codex doesn't show a single one.
Not surprising, when I looked at those small Stars, I often saw things like 0.29 Solar Mass.
No idea why Stellar Forge misinterpreted and classified these Dwarfs as "Giants" in the GALmap/System Maps - but to me it seems the GALmap/System Maps are typically wrong and the Codex right.

But that causes a split between Codex and Galaxy Map/System Map Info.
 

ChipStar65

ChipStar65
FalconFly said:
^^^^ This pretty much

I've scanned plenty of so-called "Giants" as well (i.e. M, K) - yet the Codex doesn't show a single one.
Not surprising, when I looked at those small Stars, I often saw things like 0.29 Solar Mass.
No idea why Stellar Forge misinterpreted and classified these Dwarfs as "Giants" in the GALmap/System Maps - but to me it seems the GALmap/System Maps are typically wrong and the Codex right.

But that causes a split between Codex and Galaxy Map/System Map Info.
Click to expand...
Thanks for that information. However, they are "giants" regardless of actual size, as I posted above, because that term relates to spectral class and age/evolutionary status, not just physical size. If it evolved from a very small size to twice its diameter or more it would truly be a giant among its kind, though not in the overall spectrum of stellar sizes.

It's thought the Sun will eventually become a red giant, and it would be spectacularly large by comparison to its size today, but still be dwarfed by other giant stars, especially the hotter high-mass stars that formed as giants instead of evolvng into them. Among the stars, it seems "giant" is a relative term.
 

Deleted member 38366

D
ChipStar65 said:
Thanks for that information. However, they are "giants" regardless of actual size, as I posted above, because that term relates to spectral class and age/evolutionary status, not just physical size. If it evolved from a very small size to twice its diameter or more it would truly be a giant among its kind, though not in the overall spectrum of stellar sizes.

It's thought the Sun will eventually become a red giant, and it would be spectacularly large by comparison to its size today, but still be dwarfed by other giant stars, especially the hotter high-mass stars that formed as giants instead of evolvng into them. Among the stars, it seems "giant" is a relative term.
Click to expand...

According to the Definition of "Giant Star", they'd still have to be significantly larger than a main sequence star of the same class and surface temperature.
Unless I overlooked something, that typically wasn't the case.

Looked rather like 100% generic, normal main sequence stars instead, both in size, mass and temperature. Hence, they actually weren't Giants indeed.

Oddly, this only ever occurred (as far as I can tell) widespread with M and K "Giants".
B Star Giants for example always seemed correct. A Giant always was a true Giant with these, at least in my experience.
 

ChipStar65

ChipStar65
A little reseacrh reveals that the classification of a star of this mass as a red giant is not likely or maybe even not possible. Red dwarf stars of low mass do not exhaust their hydrogen fuel (a prerequisite for expanding into giant stage) within the known age of the Universe -- estimates say some could burn H for trillions of years. So true red giants only occur in stars of mass 0.3 to 8 solar masses. This star is just below the lower threshold of that range.
 

ChipStar65

ChipStar65
Straha Yeagar said:
ANd then to really mix things up, Red Super Giants are K class on the galmap
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This sounds more plausible. The classifications are based on surface temperature, and the surface of stars in the evolutionary giant/supergiant stage are much cooler than their main-sequence forms. Our Sun is class M but will likely evolve to a class M or K red giant after it exhausts its hydrogen supply and begins to burn helium. Betelguese is an example of a red supergiant that is nominally class M.
 
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