In every star system I remember seeing, all the stars present have the same ages. Can anyone point me at a system where there are stars of different ages present?
Wanted: Systems with Stars of different Ages
- Thread starter Jackie Silver
- Start date
In our corner of the galaxy, it is exceedingly rare that a star that wasn't formed from at the same time from the same nebula would be captured by another. This is because the relative velocities of unrelated stars are quite high, and the distances between stars is very large, and in order for one star to be captured, it needs to lose energy some how, via internal or external friction (tidal forces, hitting accretion disks, etc). Theoretically, your best bet for finding a star system like this would be in the central bulge where the close proximity of stars increases the likelihood of capture. However, they also have higher absolute velocities due to their proximity to the galactic orbital center. So there would be an ideal distance from the core where stars where close enough to interact physically, but not going too fast with too much energy to form a stable binary system.
There are three possibilities when two stars interact:
1) They fly past each other and deflect their tragectories
2) They collide and merge into one larger star if they are going slow enough, or vaporize sending their matter to opposite ends of the galaxy if they are going too fast
3) They pass close enough at a slow enough velocity to lose kinetic energy (velocity/angular momentum/ etc) via some kind of mechanical braking, and form a stable binary star
Here is an interesting video on stellar collisions featuring one of my old professors:
[video=youtube;ZucjiKb6IRI]https://www.youtube.com/watch?t=32&v=ZucjiKb6IRI[/video]
There are three possibilities when two stars interact:
1) They fly past each other and deflect their tragectories
2) They collide and merge into one larger star if they are going slow enough, or vaporize sending their matter to opposite ends of the galaxy if they are going too fast
3) They pass close enough at a slow enough velocity to lose kinetic energy (velocity/angular momentum/ etc) via some kind of mechanical braking, and form a stable binary star
Here is an interesting video on stellar collisions featuring one of my old professors:
[video=youtube;ZucjiKb6IRI]https://www.youtube.com/watch?t=32&v=ZucjiKb6IRI[/video]
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Ach, you're right I s'pose. I had it in mind that it was uncommon but occasionally possible and that the "occasionally" would be enough for someone somewhere to have seen it if modelled in-game! (...and not "system_age" being a variable belonging to the star system rather than to the individual stars 
) I think capture post-formation may be more plausible in systems which are already multiple, where there are various different bodies that can bleed off the energy of an approaching object? Or maybe if some hapless dim star found itself slowly wandering into a star-forming region at the right time? (I've no idea what the stellar wind from a very dim dwarf does to a nebula, if it disrupts everything around or if it's so weak that it just wanders through - could then run into some big stars in the process of formation and find itself caught by the same mechanisms that would catch it if it was forming there?)
) I think capture post-formation may be more plausible in systems which are already multiple, where there are various different bodies that can bleed off the energy of an approaching object? Or maybe if some hapless dim star found itself slowly wandering into a star-forming region at the right time? (I've no idea what the stellar wind from a very dim dwarf does to a nebula, if it disrupts everything around or if it's so weak that it just wanders through - could then run into some big stars in the process of formation and find itself caught by the same mechanisms that would catch it if it was forming there?)Hats off for the amount of data you are collecting about the various systems. I suspect many travellers, like myself, often don't look at things like relative ages of the stars. In fact with stars if I see an unusually big one I may note the size, but that's about it. On my current trip I'm collecting screen shots of all the terraformables and ammonia worlds, and will share once I've sold the data.
Since proto stars aren't techincally stars yet (even though they look very much like stars in this game), I am going to say the game probably starts the clock at the time of gravitational collapse into a proto stellar disk, not the beginning of any particular phase of stellar evolution, or any transition to or from the main sequence.
That is a good question, and I honestly don't know the answer. I do know that larger planets in our own solar system tend to chuck as many things towards the earth as they deflect away, and the acceleration (and therefore kinetic energy) is increased in either case, so I am going to say that multiples or binaries would either be a wash or would more likely increase the speed of the star passing through the system. Alot of the dynamic depends on the plane of the orbit and the vector of the incoming star. Part of the problem is that if the incoming star is bleeding enough energy (through friction with disk material or tidal forces) to be captured, then it likely won't have a stable orbit, and will ultimately crash into the capturing star system. Thus, either forming a new single star, or hitting the reset button on the system and form a new (series of) proto-stellar disk(s) resulting in a reconfiguration into a new star system (possibly binary or single etc) much in the same way that the earth-moon system formed from a collision of a large impact event of with the later stage primordial earth. In either case, the age of the star would effectively be reset since the core would have been remixed and altered to a more hydrogen rich environment.
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Well... you're probably right.
Oh, by the way... what about the neutron stars (or black holes)? What should be considered as their date of birth - time when original star started fusion in its core, or the moment it was destroyed in supernova explosion and transformed into (vastly) different type of stellar object? Another thing: it has been theorized that new star may be born out of the gas cloud released from supernova - shouldn't at least some of those dwarves orbiting neutron stars/BHs appear younger?
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That's almost a philosophical question. By some measurements my own approximate age is 13.8 Billion years
On a more practical note, the main sequence lifetime of neutron and BH precursors is insignificant on cosmic scales. Measured in mere millions of years. It's also possible for an object to pretty much go straight to the black hole phase in the early universe, and this is one theory for the composition of formerly-baryonic galactic dark matter, including Sgr A*
super nova remnants don't stay put. They spread out and mix with the interstellar gas. And that is what forms new stars. Every element on the periodic table heavier than iron was formed in a supernova implosion. That includes all of the heavier elements that make our planet and our human bodies possible. So we ourselves are quite literally supernova remnants.
On a more practical note, the main sequence lifetime of neutron and BH precursors is insignificant on cosmic scales. Measured in mere millions of years. It's also possible for an object to pretty much go straight to the black hole phase in the early universe, and this is one theory for the composition of formerly-baryonic galactic dark matter, including Sgr A*
super nova remnants don't stay put. They spread out and mix with the interstellar gas. And that is what forms new stars. Every element on the periodic table heavier than iron was formed in a supernova implosion. That includes all of the heavier elements that make our planet and our human bodies possible. So we ourselves are quite literally supernova remnants.
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I strongly suspect that the stellar forge only contains one 'age' for each system and that age is applied to each stellar body within it. So systems with black holes as the main star are old (billions of years) whereas ones where they orbit class O or proto-stars can be as young as 1 million years.
This is actually quite impossible, unless one of them has been captured. Stars form in a solar system usually at the same time (more or less a few hundred years). Stars form when the original gas cloud of a system crumble upon itself.
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this is probably true. I have been meaning to go down to Orion and survey the ages of the objects in the star formation column, if any place has a high enough density with the possibility of stellar capture of low velocity stars it would be that region.
Yesterday i spotted a system with a black hole and 2 TTauri. One TTauri was several times bigger and "heavier" than the other. All 3 objects had exactly the same age: 4 million years. So i suppose the starforge calculates age of a system, the age of the black hole is calculated when black hole was formed, not when the star where it comes from was formed.
Also i have seen several "Supergiant" (aka past main sequence) stars that were very young. A K supergiant with 130 million years, if i'm not mistaken the K star in main sequence should have few dozen Billion years of life span. So i guess the age of the Orange Supergiant is calculated when the main sequence ends, but that object should be WAY older.
In game probably we won't find system with stars of different ages, unless they change something in the starforge.
Also i have seen several "Supergiant" (aka past main sequence) stars that were very young. A K supergiant with 130 million years, if i'm not mistaken the K star in main sequence should have few dozen Billion years of life span. So i guess the age of the Orange Supergiant is calculated when the main sequence ends, but that object should be WAY older.
In game probably we won't find system with stars of different ages, unless they change something in the starforge.
A black hole forms from a massive short lived star (main sequences age measured as little as 1 Million years) . So all 3 stars could easily have been formed from dust a mere 4 million years ago. The T Tauri phase is roughly 100 million long.
Good observation! For clarity, spectral class K means that the star is red, but that by itself doesnt tell you how old it is. Class K supergiants are actually young stars, that were formerly massive blue stars (eg Class A etc) that have drifted off the main sequence and are now cooler and redder but still quite massive and relatively young and are now the same color as a red dwarf, but not the same size or with the same lifespan. The life span is determined by the mass, not the color. Higher mass means shorter life. So a 130 million year old red supergiant class K star is also accurate.
edit: btw congrats on finding a very rare star, and a prime candidate for the next galactic super nova. Please post the data if you have a screen shot
Good observation! For clarity, spectral class K means that the star is red, but that by itself doesnt tell you how old it is. Class K supergiants are actually young stars, that were formerly massive blue stars (eg Class A etc) that have drifted off the main sequence and are now cooler and redder but still quite massive and relatively young and are now the same color as a red dwarf, but not the same size or with the same lifespan. The life span is determined by the mass, not the color. Higher mass means shorter life. So a 130 million year old red supergiant class K star is also accurate.
edit: btw congrats on finding a very rare star, and a prime candidate for the next galactic super nova. Please post the data if you have a screen shot
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Yeah, I suppose that the material released in supernova event is being blown away in all directions so fast and so far that it cannot possibly slow down and re-accumulate into the new star which would then remain in orbit of recently born neutron star/black hole. Even if some of this material stays in relative vicinity, it should probably simply fall back onto to the neutron star/BH.
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A black hole forms from a massive short lived star (main sequences age measured as little as 1 Million years) . So all 3 stars could easily have been formed from dust a mere 4 million years ago. The T Tauri phase is roughly 100 million long.
Good observation! For clarity, spectral class K means that the star is red, but that by itself doesnt tell you how old it is. Class K supergiants are actually young stars, that were formerly massive blue stars (eg Class A etc) that have drifted off the main sequence and are now cooler and redder but still quite massive and relatively young and are now the same color as a red dwarf, but not the same size or with the same lifespan. The life span is determined by the mass, not the color. Higher mass means shorter life. So a 130 million year old red supergiant class K star is also accurate.
edit: btw congrats on finding a very rare star, and a prime candidate for the next galactic super nova. Please post the data if you have a screen shot
I went through my database, and the youngest giant i've found it's not orange but Blue.
Gal Map Info Tab says O8 IIIA, so if i'm not mistaken it's already out of main sequence. And in fact in gal map it's a gigantic Blue sphere. And even if you zoom completly out it's visible as a blue dot.
But in system description they give a main sequence O description, wich in my opinion is bug given the values. It has < 1 million years, 82 solar masses and 149 solar radii
In your opinion it's about to go supernova?
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The blue super giant will go nova in the future as well, but it's actually the RED supergiant that I was referring to. The 130 million year old red supergiant used to be a hotter bluer star as well, and depending on it's initial mass, it is likely going to go nova a little sooner than the blue star. Although at ~82 solar masses, the blue giant doesn't have much longer to live either.
they will be different kinds of novas though. The Redgiant is likely a lower mass star and will become a neutron star. The currently type O star will become a black hole or a neutron star depending on how much metal is in the star. Here's a graph that explains the initial mass and the outcome. The red super giant in either one of the two categories. The term "metal" in astronomy means anything heavier than Hydrogen or Helium.
| Core collapse scenarios by mass and metallicity Cause of collapse | Progenitor star approximate initial mass | Supernova Type | Remnant |
| Electron capture in a degenerate O+Ne+Mg core | 8–10 | Faint II-P | Neutron star |
| iron core collapse | 10–25 | Faint II-P | Neutron star |
| iron core collapse | 40–90 with low metallicity | None | Black hole |
| iron core collapse | ≥40 with near-solar metallicity | Faint Ib/c, or hypernova with GRB | Black hole after fallback of material onto an initial neutron star |
| iron core collapse | ≥40 with very high metallicity | Ib/c | Neutron star |
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