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Author Topic: Will UBox2 ever have active depiction of stellar structure/internal dynamics?  (Read 5149 times)

vmorgo

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Grumble grumble.

I'm grumbling again.  Sorry.  Just a quick one for the devs...  Stars from mid-type F (about 1.5 solar mass) down have convective outer envelopes.  Below 0.5 solar masses, stars are entirely convective.  Above 1.5 solar masses, cores are convective and outer envelopes are actually radiative.

This would seem to suggest that larger main-sequence stars should NOT be portrayed in UBox2 as having convection cells on their surfaces; rather that their surfaces should be, essentially, smooth and relatively uniform (perhaps just a blaze of light?). 

It is interesting to note that, at about the same point (mid type F) the rotational speed of stars dramatically increases from a matter of weeks to a matter of days or even hours.  This very rapid rotation, in conjunction with convective cores in large stars suggests that such big stars might actually have extremely strong magnetic fields, and, therefore, they may very well have dramatic flares, CMEs and, possibly, quite large star-spots.  I am wondering if Jennifer (at Giant Army) or anyone else might comment on this and, if I am wrong, please correct me.  If I am correct, I am sincerely hoping that the devs will address this in their next release and depict the larger stars as having properly radiative surfaces and no convection cells visible!

Again, this applies only to main sequence stars.  Giants, supergiants and hypergiants are a different story altogether!

« Last Edit: December 23, 2015, 05:51:52 AM by vmorgo »

vmorgo

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Re: The Star Grumbler
« Reply #1 on: December 11, 2015, 01:38:37 PM »
Another thought #1:

White dwarfs do NOT have convective surfaces.  Please correct this (and pulsars, too--I haven't looked at one, yet, but if...) so that these bodies do not display convection cells on their surfaces!

vmorgo

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Re: The Star Grumbler
« Reply #2 on: December 11, 2015, 01:41:59 PM »
Another thought #2
If it is possible (and it may not be, depending on the model used to 'build' stars for Ubox2:) would you please fix it so that large, rapidly rotating main-sequence stars are correctly depicted as oblate spheroids?  Due to high rotational speeds, these stars tend to bloat out at the equator, so that their diameter at the equator is considerably greater than it is at the pole.  Consequently, such stars will appear to be brighter and hotter at the polar regions than they will at the equators.

Thank you!

Darvince

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I very much enjoy your posts, I didn't know about those processes you detailed above. Although I have long longed for rotation period to affect how oblate an object appears, especially since Jupiter and Saturn and (as you mentioned) high mass stars have quick rotation periods making them oblate spheroids.

Cryo

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I very much enjoy your posts, I didn't know about those processes you detailed above. Although I have long longed for rotation period to affect how oblate an object appears, especially since Jupiter and Saturn and (as you mentioned) high mass stars have quick rotation periods making them oblate spheroids.
Ah This is quite fascinating. I to wondered about this, good to see that im not the only one, also your post are quite interesting to read.Always a new bit of info to learn.

vmorgo

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Glad that you (Darvince and Cryo) enjoy my "star-grumbles"....  I am honored....  <humbly bows>  Way I see it, Universe Sandbox is tragically miscategorized as a "game".  It isn't.  It's an advanced scientific and astronomical simulator--it is a tool and could very well be used in training and in the classroom, just as Microsoft's Flight Simulator is often used in training new pilots.    I am hoping that the nice folks at Giant Army will choose to market it in this way, as well as as a game (They shouldn't give up the 'game' angle, as that would eliminate a large chunk of their potential audience)--they should just ADD the educational/research angle as well as there is so much to be learned through this program).  I am, therefore, being a grumbling PITA because I want Giant Army to extend and expand upon the accuracy of this fantastic tool so that it ever more realistically (within the constraints of current home computer technology) depict stars, planets and other items in outer space.  I'd just as happily see less focus on dramatic explosions and more on stellar dynamics, planetary evolution given changes in environment, temperature, distance from sun(s), etc.) 

Indeed, it was through the use of this program that I learned that an earthlike world orbiting within the habitable zone of a red dwarf sun is extremely unlikely to be have any moons, as well as that an earthlike world orbiting a blue giant would have to be so far away from its primary that such a world's sun would appear to be just a tiny, extremely bright, 'star' in the sky.

Such fascinating discoveries lead to further research that made me realize that the sky of a world orbiting that red dwarf would almost certainly be a pinkish orange, rather than blue, and that plants on the surface of that world would probably appear black to us, rather than green.

Another interesting thought is that large main-sequence stars (stars above that 1.5 solar mass/mid-F boundary), where fusion takes place in their cores mainly through the CNO process rather than the triple-alpha process (as seen in the sun and smaller stars) tend to last only a billion or two years, (for the smaller ones) and only a few tens or hundreds of millions of years for the largest ones.  It is not very likely that worlds orbiting such stars, if any even formed amidst such prodigious stellar winds, would have time to evolve to the point of being able to support any kind of life beyond the most primitive of bacteria, if even that, before their suns aged to the point of supernova.

It's all quite fascinating, isn't it?

Gordon Freeman

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Awesome ideas, looks like this board still has some hope :D

especially since Jupiter and Saturn and (as you mentioned) high mass stars have quick rotation periods making them oblate spheroids.

Jupiter does actually appear oblate in US2, last time I checked

vmorgo

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Oh, I think there are some pretty cool posts in here....  one just has to dig a little!  :)

You might enjoy this entire site, but a particularly interesting image is shown a little bit more than halfway down the page, regarding the fastest spinning star VTFS 102

 http://minsex.blogspot.com/2011_12_01_archive.html

Darvince

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I agree that I'm kind of saddened that they've decided to focus much more on the game part of the development than the simulation part of the development. Although, having collisions and explosions, volcanoes, etc, developed well can give them more cash money to be able to develop the less "exciting" parts more thoroughly, such as everything you've mentioned in this topic.