Orange 'Giant' is smaller than the Sun

[thundernuns]

So I've been hopping around doing missions to increase my fed rank, and I stumble upon a system called Rana, as I go to jump, it tells me 'orange_giant'. When I enter though, it doesn't seem giant, and sure enough in the system map:
Mass-0.4922
Radius-0.6914

It is listed as a K1 IV star...so anyone know how this is a giant?

 

[varonica]

So I've been hopping around doing missions to increase my fed rank, and I stumble upon a system called Rana, as I go to jump, it tells me 'orange_giant'. When I enter though, it doesn't seem giant, and sure enough in the system map:
Mass-0.4922
Radius-0.6914

It is listed as a K1 IV star...so anyone know how this is a giant?

Interesting, that star type is generally referred to in Astronomy as either a K Type or Orange Dwarf, according to it's mass it sits slightly above the normal smallest size of 0.45 solar masses for that type of star. I wonder if it's actually a bug and the label should read "Orange Dwarf", not "Orange Giant", so referring to the astronomical name rather than it's actual size. Worth putting in a bug report about maybe?

 

[thundernuns]

Interesting, that star type is generally referred to in Astronomy as either a K Type or Orange Dwarf, according to it's mass it sits slightly above the normal smallest size of 0.45 solar masses for that type of star. I wonder if it's actually a bug and the label should read "Orange Dwarf", not "Orange Giant", so referring to the astronomical name rather than it's actual size. Worth putting in a bug report about maybe?

hhmmm maybe

 

[MattG]

If it's class IV, isn't it a subgiant and potentially on it's way to being a giant? (*shrug* not an astronomer )

 

[thundernuns]

If it's class IV, isn't it a subgiant and potentially on it's way to being a giant? (*shrug* not an astronomer )

eeer I don't know

Jackie Silver, I summon thee...

 

[CMDR Space Lurker]

It is the Little-est Giant!.. Might qualify for some astronomical record in the game!..
Though I think it is a bug.. seems too low-mass to ever go subgiant... I think. (Not an astronomer but have an intermittent interest in the subject )

 

[thundernuns]

It is the Little-est Giant!.. Might qualify for some astronomical record in the game!..
Though I think it is a bug.. seems too low-mass to ever go subgiant... I think. (Not an astronomer but have an intermittent interest in the subject )

I checked the UC record breakers and it doesn't mention giants in the K class :C

 

[Andrew Gaspurr]

The term 'giant' is generally misleading as these stars are not necessarily greater but more luminous than Sol. In ye olden days folks thought that all brighter stars than the regular ones must be giant stars, hence 'brighter = bigger = giant'. Rana is a K1 IV star, meaning that it is cooler than Sol (which is a G2 type). Sol has a surface temperature of 5,700 K whereas Rana has some 4,000 K. But with a luminosity type of IV it is more luminous than a regular K V main sequence star. It's not necessarily bigger.

So K1 IV is more luminous than K1 V but not more luminous than G2 V.

When you enter the details in the Luminosity Calculator you will find out that Rana has 0.28 times the luminosity of Sol. Plus, with an age of 10 billion years it is expected to have left the main sequence 'recently' and will evolve into a Red Giant once its helium will fuse in its outer layers. This means the ELW of Rana 1 is doomed within the next 100 million years or so.

Massive stars (O, B, A) tend to be or are almost exclusively more massive and have more radius than Sol but that also applies to massive main sequence stars.

 

[thundernuns]

The term 'giant' is generally misleading as these stars are not necessarily greater but more luminous than Sol. In ye olden days folks thought that all brighter stars than the regular ones must be giant stars, hence 'brighter = bigger = giant'. Rana is a K1 IV star, meaning that it is cooler than Sol (which is a G2 type). Sol has a surface temperature of 5,700 K whereas Rana has some 4,000 K. But with a luminosity type of IV it is more luminous than a regular K V main sequence star. It's not necessarily bigger.

So K1 IV is more luminous than K1 V but not more luminous than G2 V.

When you enter the details in the Luminosity Calculator you will find out that Rana has 0.28 times the luminosity of Sol. Plus, with an age of 10 billion years it is expected to have left the main sequence 'recently' and will evolve into a Red Giant once its helium will fuse in its outer layers. This means the ELW of Rana 1 is doomed within the next 100 million years or so.

Massive stars (O, B, A) tend to be or are almost exclusively more massive and have more radius than Sol but that also applies to massive main sequence stars.

+1

It makes sense now, although 10 billion years seems to be quite short for a K star to die

 

[Andrew Gaspurr]

+1

It makes sense now, although 10 billion years seems to be quite short for a K star to die

Not if that luminosity type of K is a transition phase. K is not a fixed state, Rana may have been a G star until 'recently'. Sol will also become dimmer at first after a total hydrogen burning phase of 10 billion years. Eventually, it will evolve into a cool but 'apparently' luminous red giant.

 

[thundernuns]

Not if that luminosity type of K is a transition phase. K is not a fixed state, Rana may have been a G star until 'recently'. Sol will also become dimmer at first after a total hydrogen burning phase of 10 billion years. Eventually, it will evolve into a cool but 'apparently' luminous red giant.

I knew that stars can change type, but it seemed odd that it is so light. But now I remember stars lose mass when they expand

Or I may be confusing facts in my head [wacky]

 

[Jackie Silver]

Jackie Silver, I summon thee...

As noted, the terminology of dwarfs and giants can be misleading, but I would expect in reality that a K IV (subgiant) would be a star of a little under solar mass and considerably over solar age, moving up the red giant branch and larger than the Sun.

In the game... ^^ There are a number of peculiarities (particularly with massive, hand-authored stars) where the radius is absurdly small for the mass, but this isn't one of those. As far as I can tell the Stellar Forge either does not simulate, or very strongly abbreviates the red giant branch; if you look at an HR diagram of a general sample of real stars the RGB is clearly visible; if you look at an equivalent HR diagram in Elite you see a line along the main sequence and a line of giants but nothing in between. I don't understand exactly what's going on, but where the real process produces a drawn out band stretching above the main sequence to the giants, in the game it's an abrupt transition from one to the other, and proc-gen sub-giants or smaller giants are extremely rare. For low mass stars you're either an approximately 1 solar radius main sequence star or an approximately 30 solar radius giant, no stops in between.

I think that what's happening is that the game has "bands" of luminosity for each temperature, and this star is slightly higher luminosity than the K VA band; although it's in no way a giant, the game reaches for the next luminosity band up, and calls it K IV, instead of realising that it's just a brighter (in game terms) K VA. I think this is the only way that the game produces subdwarfs; it doesn't simulate them as such, but in exceptional circumstances a main sequence star that is particularly bright for its temperature is called a subdwarf.

Hope that makes sense, I'm typing while flying...

 

[thundernuns]

As noted, the terminology of dwarfs and giants can be misleading, but I would expect in reality that a K IV (subgiant) would be a star of a little under solar mass and considerably over solar age, moving up the red giant branch and larger than the Sun.

In the game... ^^ There are a number of peculiarities (particularly with massive, hand-authored stars) where the radius is absurdly small for the mass, but this isn't one of those. As far as I can tell the Stellar Forge either does not simulate, or very strongly abbreviates the red giant branch; if you look at an HR diagram of a general sample of real stars the RGB is clearly visible; if you look at an equivalent HR diagram in Elite you see a line along the main sequence and a line of giants but nothing in between. I don't understand exactly what's going on, but where the real process produces a drawn out band stretching above the main sequence to the giants, in the game it's an abrupt transition from one to the other, and proc-gen sub-giants or smaller giants are extremely rare. For low mass stars you're either an approximately 1 solar radius main sequence star or an approximately 30 solar radius giant, no stops in between.

I think that what's happening is that the game has "bands" of luminosity for each temperature, and this star is slightly higher luminosity than the K VA band; although it's in no way a giant, the game reaches for the next luminosity band up, and calls it K IV, instead of realising that it's just a brighter (in game terms) K VA. I think this is the only way that the game produces subdwarfs; it doesn't simulate them as such, but in exceptional circumstances a main sequence star that is particularly bright for its temperature is called a subdwarf.

Hope that makes sense, I'm typing while flying...

It made sense to me [up]

Thanks for hearing my call, Dovahkiin

 

[Andrew Gaspurr]

It could also be a variable star exhibiting its current luminosity in the 'upper' parts but I doubt FDev had a mode for this installed in their Stellar Forge. Watch for patch notes saying something like 'reverted all variable stars to another luminosity class'.

 

[SpaceMonkeyz]

I recently Jumped in to a red giant system, M class and I was greeted with a red star about the size and mass of a red dwarf, HA!

 

[marx]

"13 giant stars you would NOT believe are smaller than the Sun!"

 

[Andrew Gaspurr]

Yeah, that's the game. Red Dwarfs do contract after each phase of their stellar nucleosynthesis but obviously not enough to make them red dwarfs again. When they start to inflate again they also shed lots of their mass into space, the result being a white dwarf in the end (which is pretty much the glowing core remnant. But it's not a red dwarf.

 

[CMDR AKIRA MASAKARI]

I recently Jumped in to a red giant system, M class and I was greeted with a red star about the size and mass of a red dwarf, HA!

The proc generated out of main sequence stars can have a wrong description either in the gal map info panel or in the galaxy map one. I have many examples of stars that were regular and had a giant description and vice versa.

Rana is not proc generated tough, so it's likely to be as Andrew and Jackie say.