Estimating the Size of The Bre'el Moon

[Mith]

http://tng.trekcore.com/gallery/thumbna ... 52&page=19
This is the look of the sun.

There's a bit of a problem with the 12,000 K surface temp. That star would be blue, not orange yellow, if it was a main sequence star.
So, it would probably be a giant/super giant, which means the radii and area would be greater.

Different regions of a star can be different temperatures for difference reasons. The not-particularly-dense-yet-reddish-orange-tinted chromosphere tops 12000 degrees in its outer layer (goes up to 50000, in fact), although not particularly dense.

Thermodynamics strongly suggests that we not have a cooler substance spontaneously heating a warmer substance.

Frankly, given that heavy filtering is necessary to display any sort of visuals of a ship running around the interior of a star, I'm not inclined to rely on the color of the plasma as necessarily accurate, regardless of what layer it turns out to actually be.

I don't understand it. The ship was not in the chromosphere, but farther, somewhere in the corona.
Any hull heat up would be due to what the shield couldn't cope with.

Not true per say. The shields of a starship aren't designed to deflect a constant rate of energy. Most uses of shields are hostile starships, which even with a high rate of fire, are not going to be constantly battering at the entire shield grid for hours, but rather a short burst over a few seconds. This gives the shields the chance to disperse it over a large portion of the grid, absorb some energy, and slowly restore the damage. But a constant stream of heat and radiation is hard to deal with for a system like that. It further complicates matters when we heard no indication that the Enterprise D was taking shield damage from the Corona (or at least, not at a rate worth mention), which suggests that what we saw was leak through, and that was the point of metaphasic shielding; it was designed to more effecitvely disperse heat and radiation over the shield grid, because otherwise, the shields of a starship could last for only so long before the leakthrough radiation and heat kills the crew.

We've seen that even without metaphasic shielding, Klingon Bird of Prey, Constitution Classes, and Galaxy classes can easily withstand close contact with a star for a short period of time with the crew just being uncomfortable.

[Mr. Oragahn]

Well, I'm not sure we're disagreeing. What I to know is just how luminous you think that star was.

[Mith]

Well, I'm not sure we're disagreeing. What I to know is just how luminous you think that star was.

Not really disagreeing to begin with, I just wanted to point out a few factors that should be taken into consideration.

[Mike DiCenso]

Whatever else, as is pointed out, the star is unusually hot. To get 12,000 k through the shields (heavily damaged by combat) suggests a very hot and luminous star compared with our own Sol. I believe JMS suggested at least twice that of Sol, which would still fit with the visual FX of the star.
-Mike

[Mr. Oragahn]

Whatever else, as is pointed out, the star is unusually hot. To get 12,000 k through the shields (heavily damaged by combat) suggests a very hot and luminous star compared with our own Sol. I believe JMS suggested at least twice that of Sol, which would still fit with the visual FX of the star.
-Mike

This is where I disagree.
The corona is hotter, for any star. The ship was in the corona. The visuals point to a star which is more orange than yellow.
I didn't get what JMS was trying to say with his link.
Besides, if the temperature of the hull was a consequence of the radiations from the photosphere, only one side of the ship would be concerned, and the ship would just have to roll continuously to avoid having the same side facing the star.

[Mike DiCenso]

Except that the solar corona is very difuse by comparison to say, the photosphere or the chromosphere. The E-D in "I, Borg" [TNG5] hid inside a stellar chromosphere to hide from the Borg for a significant period of time, and did not suffer any damage. This time neither the E-D herself, nor her shields were damaged to begin with. As for a star's color, it may be an F type star, which might explain the odd color and the higher temperature.

As for rotating the hull, I think that might be a bit of a problem given that they were under close pursuit by the Borg ship, and had to maintain impulse power on full in order to reach the star before they got caught.
-Mike

[Mr. Oragahn]

Except that the solar corona is very difuse by comparison to say, the photosphere or the chromosphere.

Well, sure, the molecules in the corona would be more excited, but the extremely low density doesn't allow a high luminosity, so there would be less radiations from the corona itself within one cube meter.
Still, there are those things which heat up the corona. For the moment, it's considered to tbe magnetic fields.
Passing through a corona is less noticeable since these fields would affect a low density. But then think about what the magnetic fields would do to the much much denser materials of a starship, notably the hull.
What would heat up the extremely low and local region of gas would to millions of kelvin also greatly affect denser materials present there.

The E-D in "I, Borg" [TNG5] hid inside a stellar chromosphere to hide from the Borg for a significant period of time, and did not suffer any damage.

How long?
What kind of star was that?

This time neither the E-D herself, nor her shields were damaged to begin with.

When you say this time, you mean in "I, Borg"?
In the episode we're looking at, if I got it well, the E-D did get shot several times by the bizarrely shaped Borg ship, which would explain the weakened shields.

As for a star's color, it may be an F type star, which might explain the odd color and the higher temperature.
-Mike

Yes, that's why I suggested it could be a giant earlier on, but then the increase of luminosity (2 to 6 times that Lsun as far as I've seen) would be overbalanced by the size, area and thus intensity of a star of such dimensions.

[Roondar]

We're assuming that the hull temperature is 100% due to the stars radiation. That would be unlikely, since the shields (which where supposed to protect the ship) where still up at the time.

An option would be that the Enterprise gets rid of excess heat (partially or completely) through radiation from the hull. Since shields are not going to be 100% efficient and are not designed for stellar entry in the first place, an area where the ambient temperature is really high (say 6000K) could lead to a situation in which the extra heat generated by keeping the ship shielded (which would be the other 6000 or so K - unless shields perform magic) eventually needs to be pumped out of the ship through the hull.

This is the classic 'heat death' for heat sink shields: once your capacity to accept heat is exhausted your ship will start to heat up, or in this case the hull.

It even fits with the rising temperature: the shields where still functional, they kept the stars radiation out so the E-D should not have heated up at all until they failed if they just blocked energy completely. In my suggested model this is no problem because the shields actually are holding out the radiation but have heat capacity issue.

It also explains why the E-D (and other Federation starships) can take lots of thermal damage even when their shields are gone (example: the 400GW of thermal damage they took in the episode with the Husnock. The hull didn't even start glowing) - if they build their ships to radiate heat away after it hits them a non-active shield is no problem until you reach the radiation limits.

At any rate, 12000K (or C) is an insane figure for any material to bear without melting ;)

[Mike DiCenso]

Except that the solar corona is very difuse by comparison to say, the photosphere or the chromosphere.

Well, sure, the molecules in the corona would be more excited, but the extremely low density doesn't allow a high luminosity, so there would be less radiations from the corona itself within one cube meter.
Still, there are those things which heat up the corona. For the moment, it's considered to tbe magnetic fields.
Passing through a corona is less noticeable since these fields would affect a low density. But then think about what the magnetic fields would do to the much much denser materials of a starship, notably the hull.
What would heat up the extremely low and local region of gas would to millions of kelvin also greatly affect denser materials present there.

Yes, and we have seen several times where the E-D and other Trek ships has passed through G-type stellar coronas without any real harm ("Redemption Part I, and "Relics", ect). This time was very different.

The E-D in "I, Borg" [TNG5] hid inside a stellar chromosphere to hide from the Borg for a significant period of time, and did not suffer any damage.

How long?
What kind of star was that?

It appeared to be a G-type star as is typically portrayed in Trek. The time is a bit uncertain as there are obvious large cuts in the actual time since the E-D hides in the star's chromosphere while Geordi and Hugh await the Borg "rescue" ship that will pick up Hugh and take him back to the collective. At least 3-4 minutes goes by, which is comparable to the E-D's run for the star in "Descent". The estimate given until the Borg ship enters the system is three minutes, and the E-D herself is already deep in the chromosphere at this point.

This time neither the E-D herself, nor her shields were damaged to begin with.

When you say this time, you mean in "I, Borg"?
In the episode we're looking at, if I got it well, the E-D did get shot several times by the bizarrely shaped Borg ship, which would explain the weakened shields.

Yes, I mean the E-D's condition in "I, Borg", not in "Descent". She was not damaged in any way, unlike most of the other instances of "star surfing" or atmosphere skimming we have.

As for a star's color, it may be an F type star, which might explain the odd color and the higher temperature.
-Mike

Yes, that's why I suggested it could be a giant earlier on, but then the increase of luminosity (2 to 6 times that Lsun as far as I've seen) would be overbalanced by the size, area and thus intensity of a star of such dimensions.

That is not always the case. A blue O or A type supergiant, to give an extreme example, would most definitely be hotter, dispite the vastly increased surface area.
-Mike

[Mith]

Did the shields also protect the ship from the intense gravity field? Otherwise wouldn't the warp nacelles of the ship have broken off?

[Cocytus]

Personally, I doubt it. Given the tremendous forces associated with the kinds of accelerations we see in Trek, the nacelle struts have got be be just about the strongest components of the ship. In any event, the events that have been detailed here serve to emphasize the incredible resilience of Trek starship hulls.

I'm just going to thrown to other examples in here, those being "Scientific Method" and "Shadows and Symbols." In the former, Voyager survives 9000K, and the latter example fits well with Roondar's explanation of shield heat absorption, since shields were presumably still up but the interior of the Rotarran was getting pretty hot.

[Mike DiCenso]

"Shadows and Symbols" is only one example of a BoP's shields still being in good condition when it gets very close to a star, yet still suffers the bleed through effect. On the other hand, in "Redemption, Part II" is another example again of starships with combat battered shields getting close to a star, and suffering very intense bleed through.
-Mike

[Jedi Master Spock]

Whatever else, as is pointed out, the star is unusually hot. To get 12,000 k through the shields (heavily damaged by combat) suggests a very hot and luminous star compared with our own Sol. I believe JMS suggested at least twice that of Sol, which would still fit with the visual FX of the star.
-Mike

This is where I disagree.
The corona is hotter, for any star. The ship was in the corona. The visuals point to a star which is more orange than yellow.
I didn't get what JMS was trying to say with his link.
Besides, if the temperature of the hull was a consequence of the radiations from the photosphere, only one side of the ship would be concerned, and the ship would just have to roll continuously to avoid having the same side facing the star.

The chromosphere is ruddy because hydrogen atoms are emitting mostly red and infrared light as they ionize and recombine. These emission lines don't really change with temperature.

The corona itself is very deep, quite thin, and not particularly ruddy. You can see through it pretty well. Even the chromosphere is often described as an atmosphere - most of the light we see comes from the photosphere (hence the name).