Author Topic: Stellar enhancements  (Read 74307 times)

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Offline Mobius

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Since you're creating beautiful effects for my favourite systems, finish with Sol. lol

PS I want the permission to use the latest image for a forum signature. Plz


Antares is a Red Giant, with a small star near it.
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Offline Herra Tohtori

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-Raven:

Neutron stars are so small that you would need to be very very close to see them in the first place - they are only about 20-40 km in diameter. And at that distance, you should be orbiting the star really fricking fast if you didn't wish to fall onto the surface of an object that has a huge density. Not to mention that tidal forces would likely tear you and your ship into shreds that close to such massive object.

Further more, none of their possible detail - should they have any - would be visible, since they characteristically rotate very fast due to conservation of angular momentum - essentially, they maintain a lot of the momentum of the original star, but pack it into incredibly dense form, so typical neutron stars rotate several thousand times a second. They slow down slowly - very old neutron stars can rotate as "slowly" as one rotation per second...

Plus, since you're essentialy right - it wouldn't radiate very much light at all - things would be quite dark, and you wouldn't, well, actually see the star anyway. What would be more plausible would be a dual star system consisting of large shiny star and a dense neutron star or even black hole tearing plasma from the star's photosphere and sucking it to itself, which would possibly make for quite interesting backgrounds... but for now, I'd like to see upgraded normal stars first.

However, there are objects that are more like what you describe. White dwarfs essentially exist after an old star has gone nova, spawned most of its mass into planetary nebula around itself and formed a small object of the core matter - dense, yes, but nothing like neutron stars or black holes. They radiate residual heat for some time, then dim into black dwarfs.

Another type of objects would be the brown dwarfs, which are essentially protostars without sufficient mass to start fusion reaction. They too radiate residual heat and until they cool off sufficiently, their temperature is sufficient to shine visible light, much like blackbody radiation spectrum indicates. Depending from their age they could be very bright pale blue or dark glowy red, not unlike Shivan ships... Eventually they will stop radiating their own light, though, and will become more like gigantic gas planets in appearance.
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Offline Raven2001

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Ah then I was referring to the dwarfs... mixed my way around them :P

Actually thought that the dwarfs were the ones very small, extremely dense... bcoz of that " a spoon weights more than the entire earth" thingy they told us years ago :P

I stand corrected then :D
Yeah, I know you were waiting for a very nice sig, in which I was quoting some very famous scientist or philosopher... guess what?!? I wont indulge you...

Why, you ask? What, do I look like a Shivan to you?!?


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Offline Mobius

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Well they're called dwarves <--- canon plural of dwarf ---> because they look little if put near their big sisters, but they're much greater than planets(except for many dwarves).

EDIT: Anyway, the big ones usually eat their younger sisters. Most FREDders represent it using a stetched nebula bitmap...I use it too...and works fine.
« Last Edit: March 08, 2007, 01:05:58 pm by LieutenantGeneralMobius »
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If only there could be a scenario where I could make semidetached, contact, and X-ray binaries.... Making such systems would be very interesting, but at the moment I need to focus on the stars alone, whether they are detached binaries or single stars. Thankfully binary stars like Procyon and Sirius are in the Wiki, so I will be making white dwarfs for those systems.

Herra is right about neutron stars. The main form of EM radiation these stars emit are X-rays and radio. The radio jets originate from the north and south magnetic pole of the star. When these poles happen to face the Earth, astronomers are able to detect this oscillation of radio emission in extremely short, periodic pulses. In my fantasy depiction of a neutron star, which in this case happened to be a pulsar, I created my interpretation of what the radio jets would look like from each pole if radio waves were actually visible. When the time comes for me to make neutron stars, I will definitely consider realism to my creation.

Neutron stars can also be X-ray bursters. Similar to how a cataclysmic variable involving the mass transfer of stellar matter from a companion star to an orbiting white dwarf periodically explodes as a nova, neutron stars can do the same, only more violently. Basically the larger star will have filled its Roche Lobe, and at the Lagrangian Point between the neutron star and the larger companion stellar matter will begin to flow unto the neutron star. This swirling matter essentially becomes an accretion disk, and as more matter gets dumped onto the surface of the neutron star, pressure increases; hence, the the surface of the neutron star becomes hotter. Eventually it will become so hot that hydrogen will fuse, causing an X-ray burst. Very interesting stuff...

As for white dwarfs being extremely dense, so are neutron stars on a much greater scale. A typical white dwarf is planet sized, a typical neutron star is city sized. White dwarfs can have a mass between 0.5-1.44 solar masses. I believe a neutron star hits its limit at around 4 solar masses. So basically we can have a situation were we have equal masses and extremely different volumes leaving us with extremely different densities.

Since you're creating beautiful effects for my favourite systems, finish with Sol. lol

PS I want the permission to use the latest image for a forum signature. Plz


Antares is a Red Giant, with a small star near it.

Of course, I will get to the Sun eventually.... even though its last on my list in terms of luminosity class,  :D. Since I know there are plenty of missions centered around the Sun in the FS universe I'll make an exception.  :yes: I like how you're telling me that you want permission and not asking for permission  :lol:. No problem at all, go ahead and use the picture as you want. As for Antares A, remember it is a supergiant. Stars like Capella and Aldebaran are giants, and Antares makes these stars look like dwarfs. As for Antares B, it's infinitesimal compared to Antares A, but most likely 5-10 times larger than the Sun as it is a B2.5 main sequence star.

Well, with that said its time to go to my lab. I'll see what I can do for the Sun when I get home.




 

Offline Mobius

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Sun, or Sol, is for Inferno. You know.

Thanks for the permission!
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Offline Herra Tohtori

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The main form of EM radiation <neutron>stars emit are X-rays and radio. The radio jets originate from the north and south magnetic pole of the star. When these poles happen to face the Earth, astronomers are able to detect this oscillation of radio emission in extremely short, periodic pulses. In my fantasy depiction of a neutron star, which in this case happened to be a pulsar, I created my interpretation of what the radio jets would look like from each pole if radio waves were actually visible. When the time comes for me to make neutron stars, I will definitely consider realism to my creation.

You forgot to mention that for a neutron star to become a pulsar, it must have its magnetic axis mis-aligned with its rotational axis. That's what causes the "lighthouse effect", ie. pulse signal.

X-ray and gamma pulsars work a bit differently and have several mechanisms of generating the radiation. Mainly residual heat, magnetospheric radiation and accretion disk radiation are at work there.

Anyway, a pulsar would be much better seen from a distance rather than from very near. If the pulsar is inside a nebula - which is most often the case, considering that remnants of the original star oare usually still around the place - it can cause areas of the nebula to heat, especially in case of X-ray or gamma pulsars. The area heated would look like two cones having their tips at where the pulsar is - the angle of the cones would depend on how much the magnetic axis would be mis-aligned from the rotational axis.

By the way, some pulsars actually do radiate visible light as well as radio waves - not surprising, since it's the same stuff, only different wavelength. The pulse itself wouldn't be visible, just like most people can't spot the oscillation of normal 50Hz grid electricity in light bulbs. And pulsars have much, much higher frequencies. The cone of vsible light could, however, illuminate areas of a nebula around a pulsar. So it's not really that far-fetched idea at all.

<cue Starship Troopers propaganda voice>

Would you like to learn more? :p
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Offline Raven2001

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actually the guy says: "Would you like to KNOW more?"
Yeah, I know you were waiting for a very nice sig, in which I was quoting some very famous scientist or philosopher... guess what?!? I wont indulge you...

Why, you ask? What, do I look like a Shivan to you?!?


Raven is a god.

 

Offline Herra Tohtori

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Damn. :p
There are three things that last forever: Abort, Retry, Fail - and the greatest of these is Fail.

 

Offline Raven2001

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Quick! Go edit it, Ill delete the other one :D
Yeah, I know you were waiting for a very nice sig, in which I was quoting some very famous scientist or philosopher... guess what?!? I wont indulge you...

Why, you ask? What, do I look like a Shivan to you?!?


Raven is a god.

 
 :lol: I haven't seen that movie in a while.

Oops, I did forget to mention the magnetic axis orientation relative to the rotation axis. Thanks for pointing that out. If I may ask, what is your scientific background Herra?

Well, I traveled down the luminosity class hierarchy momentarily, and here is my very first main sequence star:



What do you all think of the Sun? I added a sample Sun.rar for anyone to use if they want to try and see what the Sun looks like in-game. It will probably appear a little on the bright side since the images alone were made to look bright without any necessary increases in luminosity due to FRED. So feel free to try it out and let me know what you think. I will try my hardest to make the stars look just like the pictures I posted, minus the lens flare (which might become a nice addition in the future).

I also need to know how large the files need to be. The Sun files are much smaller than the files that I made for the fantasy stars, and I can always go back and make the files bigger if it is needed. I also need to know if I should make the glow of the star a separate image just like in the media vps, or if what I have done in the past with the single star images and black glows is acceptable. Feedback is appreciated.

The Sun can be found here: https://webspace.utexas.edu/maa945/www/Sun.rar

NOTE: The RGB value of the Sun is 255 245 242

 

Offline Admiral Nelson

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The important thing with size is to make sure that your textures are in power of two dimensions.  These are 1024 x 768; 768 is not a power of two, and Freespace suffers a performance hit.  1024 x 1024 would be better for now.  This is still a very large size for a star.

« Last Edit: March 08, 2007, 11:54:14 pm by Admiral Nelson »
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Ah, ok. That's perfectly fine, and thanks for letting me know. So what size would you recommend for a star?

 

Offline Admiral Nelson

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I'd guess that 512 x 512 would be more than enough; let's get some other opinions though.  The effect is much nicer now!
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Offline Mongoose

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I have to say that all the work you've been doing is jaw-droppingly gorgeous, especially for my astronomy-nut side. :) My gamer side does have one or two very minor concerns, though.  While achieving realistic stellar effects for all of the systems in both campaigns would be amazing, I'm slightly concerned that we might give up some of the particular shine map effects that make for such great eye candy (and screenshots).  For instance, my somewhat-limited knowledge of stellar spectra suggests that starts that emit light of a primarily greenish or violet variety aren't all that realistic, but both of those colors are featured in FS2 missions, and I've always thought that they looked really cool.  Similarly, some of the missions have featured stars of a deep reddish hue that might not be anywhere close to their actual RGB value, but still looks fantastic.  Just something to possibly keep in mind.  Another point to consider is the actual physical configuration of most of these systems.  Capella is the example I've heard used most often; while it's a multi-star system that could most likely never support a planetary system capable of sustaining human life in the real world, we know in-game that it's one of humanity's most populous colonies, and every bit of evidence from the cutscenes and mission briefings suggests that it has only one star. 

In other words, while I think that the pursuit of greater realism is a noble one, I'd prefer that it doesn't interfere too much with the gameplay experience I've come to known and love.  After all, we all know that ships probably wouldn't explode like they do in the game in actual space, we certainly couldn't hear a singe sound out there, and ships that move in the manner and speeds we see in-game make absolutely no sense...but I don't think any of us would change any of those things even if we were paid to. :p

P.S. Although I know it's no longer really being considered, I do have one more comment about the solar flare depictions.  Unless I'm mis-remembering things, I believe that the only reason SOHO is able to take such detailed images of them is because it physically blocks out the light coming from the Sun itself (which can be seen by the circular disk at the center of the previously-posted images).  In other words, if Joe Pilot were looking at one of the stars in-game (presuming he could do so without blinding himself), all he'd be able to see would be the disk of the star itself, and not the much fainter coronal material.

 

Offline Herra Tohtori

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->m2258734a:

Well, I've always been interested in natural sciences so I've read quite a lot of popular science books, especially about cosmology and astronomy, and I also remember a lot of them. Also, I study technological physics, which is more on the mathematical side of the physics...

The problem with me and physics and mathematics is that I tend to lack the longevity to learn the mathematical stuff of physics by heart. I've got a strong physical intuition - I usually know (at general level) why stuff happens and I generally can say what the results will be, and I can describe the processes involved, but number-crunching is something I've never really liked. :p

->Mongoose: Have no fear.

Even though there are no stars that directly emit green or violet light, we can simply make background art that consists of a green or violet or zebra striped nebula, and use that as a star texture - or use an invisible star texture on top of the nebula, emitting the desired colour. That's definitely within realistic parameters and will most likely satisfy the eye-candy need of yours.

Of course, realistically the nebulae would appear gray to bare eye, even up close... but who cares, really. :lol:
There are three things that last forever: Abort, Retry, Fail - and the greatest of these is Fail.

 
I was looking closely at the image that was posted with the new Sun, and I notice that you can see where the 1024 x 768 image ends. It's as if the black portions of my image are actually lighter than what they should be. Anyone else notice this?

I have finished all of the supergiants and their companions. I'd release them, but I need to find out what is the cause of this slight discoloration in the image, and if it can be corrected so the stars will blend in better with the rest of the sky.

 

Offline Herra Tohtori

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Hmm. I don't see anything too horrible - which picture are you referring to? Anyway, from the top of my head I'd say you might need to expand the contrast in some layer. Supernova lighting effect (presuming you used GIMP) does tend to effect the whole layer more or less, in which case you need to apply the contrast expanding thingy, which will make the darkest areas black (edges) and brightest areas white. After that it's a simple matter to make black transparent colour, and that should take care of the blending issues.

Here's what you can also do to find the faulty layer(s): probe the edge areas of each layer separately with the colour select tool (shortcut "O"). If you find a layer with an uniform gray colour on the edges, that's the faulty one. I would bet for the layer that has the supernova llighting filter applied onto it, but it could be any of them, especially if you've increased brightness on some of the layers.
There are three things that last forever: Abort, Retry, Fail - and the greatest of these is Fail.

 
I was referring to the last image with the new Sun that Admiral Nelson posted. I'm on a different computer now, and I don't notice the change in color that much anymore. Regardless, I'll make the correction.

You were right, the culprit is the supernova effect. I will go ahead and correct this for all of the stars I have made. I'll then provide the Supergiant.rar for anyone to use...

 

Offline neoterran

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so how do we use these file, they just go in data/effects folder ?
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