Hello HVB (and the rest of you!) I thought it might be of interest to post some of the results that I gathered when I made the calculations about a Coruscant parsec.
Based on the circumference of Coruscant's orbit, I calculated that Coruscant's orbital velocity is 45.3 km/second. That made it possible to calculate the mass of Coruscant's sun by using Kepler's law and by using Coruscant's orbital characteristics. The value I got was that Coruscant's sun has about 3 solar masses, a rather massive star in other words.
Pehaps over the top, but it was fun doing the math.
The distance of a parsec in the Star Wars galaxy
Moderator: Vympel
Yes Saxton gets 3.53 Solar masses on his Planets page.
He also notes as an unsolved question the combination of the measured mass, luminousity & radius.
I have been pondering the same off and on for a week now. It is difficult to reconsile all 3 measurements, 2 measurements are not a problem though, thats just plug-and-play in a H-R diagram.
My thoughts so far:
The radius & luminosity estimates are reconcileable as that of a K to M class subgiant of somewhere between 0.5 and 1 Msol; this however requires the rest of the mass (~3 Msol) to be present inside the orbit of Coruscant without us seeing it i.e. it is most likely a black hole - subgiant close binary system.
Now that combination is rather unlikely in and off itself (although perhaps more likely the nearer you get to the galactic core), and would almost have to have been created by a later capture event, i.e. the black hole formed seperately before it went into an orbit around the subgiant (or rather the other way round). This would almost surely cost the system all planets in orbit around the subgiant, as the orbits would become unstable. Note that the subgiant may still have been in the main sequence at this time.
Coruscant must in this scenario perforce have been placed in a stable orbit there later, by 'human' intervention, after the binary system was created and had stabilized.
I don't like this explanation, but so far that is the only answer I have come up with that fulfills all 3 'observed' measurables. Also the color gets all wrong, so the theory fails there unless we assume that Coruscant has 'streetlights' on on the dayside that 'fills in' the upper end of the spectrum, and that does not fit with the yellow corona effects we see reflected off the cityscape ... unless the lightsource is placed in one location in space: an orbital "solar emitter" or some such. And we have no evidence of any such creature.
Now of course some of the measurables are more reliable then others:
the orbital radius is based on Galaxy Guide 2 (Non-canon).
the luminosity is based on apparent luminousity at Coruscant (Canon: in TPM & AOTC Coruscant appears to be in the habitable zone) combined with the distance of coruscant from the primary: the orbital radius again (Non-canon).
the mass also appear to be based on the orbital radius and the day length, Galaxy Guide 2 again (Non-Canon).
The spectral class appears to be that of a G2 class star or thereabouts (Canon: TPM & AOTC).
Thus the most likely candidates for rejection have to be radius & (absolute) luminousity. both are supported only by GG 2, and are both non-canon & give rise to very far-fetched results.
Using only the Canon data and the lenght of the year, we end up with a star that is only slightly larger & hotter then Sol, and giving Coruscant an orbit that is only slightly longer then that of Earth. (this only requires tossing GG 2 out the proverbial airlock).
Of course this is sacrificing official data on the alter of logic, and so some people may prefer the binary system I described above, as it holds all the data intact.
(puts on helmet and waits for the shelling to start.)
He also notes as an unsolved question the combination of the measured mass, luminousity & radius.
I have been pondering the same off and on for a week now. It is difficult to reconsile all 3 measurements, 2 measurements are not a problem though, thats just plug-and-play in a H-R diagram.
My thoughts so far:The radius & luminosity estimates are reconcileable as that of a K to M class subgiant of somewhere between 0.5 and 1 Msol; this however requires the rest of the mass (~3 Msol) to be present inside the orbit of Coruscant without us seeing it i.e. it is most likely a black hole - subgiant close binary system.
Now that combination is rather unlikely in and off itself (although perhaps more likely the nearer you get to the galactic core), and would almost have to have been created by a later capture event, i.e. the black hole formed seperately before it went into an orbit around the subgiant (or rather the other way round). This would almost surely cost the system all planets in orbit around the subgiant, as the orbits would become unstable. Note that the subgiant may still have been in the main sequence at this time.
Coruscant must in this scenario perforce have been placed in a stable orbit there later, by 'human' intervention, after the binary system was created and had stabilized.
I don't like this explanation, but so far that is the only answer I have come up with that fulfills all 3 'observed' measurables. Also the color gets all wrong, so the theory fails there unless we assume that Coruscant has 'streetlights' on on the dayside that 'fills in' the upper end of the spectrum, and that does not fit with the yellow corona effects we see reflected off the cityscape ... unless the lightsource is placed in one location in space: an orbital "solar emitter" or some such. And we have no evidence of any such creature.
Now of course some of the measurables are more reliable then others:
the orbital radius is based on Galaxy Guide 2 (Non-canon).
the luminosity is based on apparent luminousity at Coruscant (Canon: in TPM & AOTC Coruscant appears to be in the habitable zone) combined with the distance of coruscant from the primary: the orbital radius again (Non-canon).
the mass also appear to be based on the orbital radius and the day length, Galaxy Guide 2 again (Non-Canon).
The spectral class appears to be that of a G2 class star or thereabouts (Canon: TPM & AOTC).
Thus the most likely candidates for rejection have to be radius & (absolute) luminousity. both are supported only by GG 2, and are both non-canon & give rise to very far-fetched results.
Using only the Canon data and the lenght of the year, we end up with a star that is only slightly larger & hotter then Sol, and giving Coruscant an orbit that is only slightly longer then that of Earth. (this only requires tossing GG 2 out the proverbial airlock).
Of course this is sacrificing official data on the alter of logic, and so some people may prefer the binary system I described above, as it holds all the data intact.
(puts on helmet and waits for the shelling to start.)
Good observation! I have visited that page several times, but never noticed that. I will take a closer look.Yes Saxton gets 3.53 Solar masses on his Planets page.
He also notes as an unsolved question the combination of the measured mass, luminousity & radius.
Hmmm, yes it's difficult to reconcile the luminosity and mass with the statement that Coruscant's sun is tiny.
No kidding. If that was the case, there would be effects on Coruscant and its sun. Extremely farfetched, although it was good and correct reasoning.The radius & luminosity estimates are reconcileable as that of a K to M class subgiant of somewhere between 0.5 and 1 Msol; this however requires the rest of the mass (~3 Msol) to be present inside the orbit of Coruscant without us seeing it i.e. it is most likely a black hole - subgiant close binary system.
Now that combination is rather unlikely in and off itself
According to some source, Coruscant is orbited by mirrors that reflect sunlight down on the planet, although they're no hint of them on-screen. I will check and see if I can find the source (EDIT: It was the Official Site's Databank http://www.starwars.com/databank/locati ... ant/?id=eu and the Insider's Guide CD-ROM that contained this information. I think it's likely that it is included in Inside the Worlds of Episode I).the theory fails there unless we assume that Coruscant has 'streetlights' on on the dayside that 'fills in' the upper end of the spectrum, and that does not fit with the yellow corona effects we see reflected off the cityscape ... unless the lightsource is placed in one location in space: an orbital "solar emitter" or some such. And we have no evidence of any such creature.
That's not from there that I got the radius of Coruscant's orbit. I found it when I looked through a copy of Inside the Worlds of Episode I, a book which holds the same status as the ICS-books. I had ignored all of these books, but found that there were some really nice-looking artwork and interesting tidbits. Galaxy Guide 2, that is WEG material, right (shivers)?Now of course some of the measurables are more reliable then others:
the orbital radius is based on Galaxy Guide 2 (Non-canon).
I would prefer a binary star system as it would solve many of the unresolved questions, but the canon does not support that theory.Using only the Canon data and the lenght of the year, we end up with a star that is only slightly larger & hotter then Sol, and giving Coruscant an orbit that is only slightly longer then that of Earth. (this only requires tossing GG 2 out the proverbial airlock).
Of course this is sacrificing official data on the alter of logic, and so some people may prefer the binary system I described above, as it holds all the data intact.
Well, not from me anyway, don't you think I'm a nice guy having a debate with(puts on helmet and waits for the shelling to start.)
?I will go and take a look at the diagrams that Saxton has included on a subpage. If it contained any good stuff, I'll be back soon.
Oh, I'm still preparing my next post about the parsec issue. Expect nothing over the weekend, though. It's Pentecost. Not that I celebrate it, but Monday is a national holiday.
EDIT: I have looked thru some books and stuff, and found that a G5 star fits some of the characteristics that has been mentioned here, both when it comes to mass and luminosity and possibly size. I will see if I can find more information on this on the Net and will get back later.
EDIT 2: I found that a star called Muscida, some 185 ly away, that displays some of the characteristics, although its radius is 15 times the Sun. Its mass was correct (3 solar masses) but it was too big. You know, that most of these stars are in a transition phase in the H-R, so it's quite difficult to find a suitable match. However, older stars would be consistent with what is expected to be in the center of a galaxy. I will continue the search.
The shelling part was because the post could be interpreted as an attempt at a Red Herring over the orbital radius length (even if it was you who started this new subject). Nobody made note of it though, so it may have been obvious that it was a different point of discussion rather then an attempt to redirect.
Anyway, if the WEG length of the orbit is repeated in IW-Ep1, we are shit outa luck trying to discount it. Damn.
I purposely called my postulated "solar emitter" such, as I also seemed to remember there being solar reflector stations in Coruscant orbit (battle of Coruscant in the X-wing series, cannot remember which book).
The reflectors would however not be able to serve the needed purpose: they can only reflect the sunlight, not change its wavelenght sharply towards the blue end of the spectrum, as would be required for my purposes.
The problem with main sequence stars (which would be the logical choice for an inhabited system) is that the Canonically observed size of the star, which Saxton describes measuring, is too large for the observer, and thus Coruscant, to be in the habitable zone unless the star's temperature is extremely low:
Luminousity is proportional to (stellar) radius^2 and temperature^4.
Apperant Luminousity (and thus energy flux) is inversely proportional to distance^2 from the star:
Planetary Surface Equibrilium Temperature(if assuming an Earth-like atmosphere):
TE = Tsol x (Rsol / (2*orbital distance))^0.5
and on the main sequence there is only one parameter of freedom: mass is linked to radius is linked to temperature is linked to luminousity, so the only way to get a fit that allows a apperant solar disk size large enough to fit Saxtons estimate without heating the planet overmuch is a M class, or if we move our accepted infalling energy range inwards to Venus' separation from the Sun, a smallish K class.
Now this gives the problems I mentioned in the last post.
The 3 or 3.53 Msol main sequence (A class) star is fine and fits all data except the observed sunset seen on Coruscant. For that to be a such star and the planet to be in the habitable zone, the Coruscant Primary should have appeared smaller then the Sun does in the Earth sky, not larger. Another problem with the 3 or 3.53 Msol main sequence star solution is the color of a such star! Vega, Altair and Sirius are examples of main sequence stars of this mass (or slightly below).
Taking the numbers in the link for a type A (3.2 solar mass) star:
80 times the luminouisty => habitable zone is at 80^0.5 AU plus/minus a wide margin, but not much below 2^0.5 of that => closest appropriate orbit is ~6.3 AU.
Radius of 2.5 solar radiuses => at 6.3 AU this star would appear as a disk 40% as wide as the sun's ~0.5 degrees i.e. 0.2 degrees. Yet the Coruscant sunset is measured by Saxton as 1.8 degrees.
In conclusion: the scriptwrites have set us a conundrum of almost Trek-ian byzantineness.
The Coruscant Primary cannot exist as described, and we must therefore assume some very exotic conditions at hand to make the discription seem consistant.
btw. the year length of 368 days: is that canon/semi-canon too or can we play around with that? (not that I think it will help us too much, but any give would be worth having).
Nobody made note of it though, so it may have been obvious that it was a different point of discussion rather then an attempt to redirect.Anyway, if the WEG length of the orbit is repeated in IW-Ep1, we are shit outa luck trying to discount it. Damn.
I purposely called my postulated "solar emitter" such, as I also seemed to remember there being solar reflector stations in Coruscant orbit (battle of Coruscant in the X-wing series, cannot remember which book).
The reflectors would however not be able to serve the needed purpose: they can only reflect the sunlight, not change its wavelenght sharply towards the blue end of the spectrum, as would be required for my purposes.
The problem with main sequence stars (which would be the logical choice for an inhabited system) is that the Canonically observed size of the star, which Saxton describes measuring, is too large for the observer, and thus Coruscant, to be in the habitable zone unless the star's temperature is extremely low:
Luminousity is proportional to (stellar) radius^2 and temperature^4.
Apperant Luminousity (and thus energy flux) is inversely proportional to distance^2 from the star:
Planetary Surface Equibrilium Temperature(if assuming an Earth-like atmosphere):
TE = Tsol x (Rsol / (2*orbital distance))^0.5
and on the main sequence there is only one parameter of freedom: mass is linked to radius is linked to temperature is linked to luminousity, so the only way to get a fit that allows a apperant solar disk size large enough to fit Saxtons estimate without heating the planet overmuch is a M class, or if we move our accepted infalling energy range inwards to Venus' separation from the Sun, a smallish K class.
Now this gives the problems I mentioned in the last post.
The 3 or 3.53 Msol main sequence (A class) star is fine and fits all data except the observed sunset seen on Coruscant. For that to be a such star and the planet to be in the habitable zone, the Coruscant Primary should have appeared smaller then the Sun does in the Earth sky, not larger. Another problem with the 3 or 3.53 Msol main sequence star solution is the color of a such star! Vega, Altair and Sirius are examples of main sequence stars of this mass (or slightly below).
Taking the numbers in the link for a type A (3.2 solar mass) star:
80 times the luminouisty => habitable zone is at 80^0.5 AU plus/minus a wide margin, but not much below 2^0.5 of that => closest appropriate orbit is ~6.3 AU.
Radius of 2.5 solar radiuses => at 6.3 AU this star would appear as a disk 40% as wide as the sun's ~0.5 degrees i.e. 0.2 degrees. Yet the Coruscant sunset is measured by Saxton as 1.8 degrees.
In conclusion: the scriptwrites have set us a conundrum of almost Trek-ian byzantineness.
The Coruscant Primary cannot exist as described, and we must therefore assume some very exotic conditions at hand to make the discription seem consistant.btw. the year length of 368 days: is that canon/semi-canon too or can we play around with that? (not that I think it will help us too much, but any give would be worth having).
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Lord Sander
- Padawan Learner
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- Contact:
368 is official. The scructure of the the year is quite specific too:
368 days = 1 year
24 hours = 1 day
5 days = 1 week
7 weeks = 1 month
10 months + 3 festival weeks + 3 holiday days = 1 year
(hours and smaller units being identical to terrestrial ones)
368 days = 1 year
24 hours = 1 day
5 days = 1 week
7 weeks = 1 month
10 months + 3 festival weeks + 3 holiday days = 1 year
(hours and smaller units being identical to terrestrial ones)
Lord Sander,
"Oderint dum metuant"
Glory to the Empire and Emperor Palpatine!
"Oderint dum metuant"
Glory to the Empire and Emperor Palpatine!
You mean "official" like in lesser-canon as is the case with the Inside the Worlds of.... and Incredible Cross-sections, right?Lord Sander wrote:368 is official. The scructure of the the year is quite specific too:
368 days = 1 year
24 hours = 1 day
5 days = 1 week
7 weeks = 1 month
10 months + 3 festival weeks + 3 holiday days = 1 year
(hours and smaller units being identical to terrestrial ones)
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Spanky The Dolphin
- Mammy Two-Shoes
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- Location: Reykjavík, Iceland (not really)
Official as in part of the EU. The ICS and ItWo books are still in the Canon level. Official is regarded as Canon as long as it doesn't contradict anything in the actual Canon.
I believe in a sign of Zeta.
[BOTM|WG|JL|Mecha Maniacs|Pax Cybertronia|Veteran of the Psychic Wars|Eva Expert]
"And besides, who cares if a monster destroys Australia?"
Remember, Obi-Wan was looking for a spaceport NOT controlled by the Trade Federation. Geonosis, being an indistrial center, probably had dealings with the Trade Federation even prior to the alliance in Ep II. They wouldnt want to fly into a space port where they are likely to encounter a Trade Federation ship.Spanky The Dolphin wrote:I think Lucasfilm said that Geonosis won't be in EIII.
I'm not going to address the first Ben-Luke thing, since that seems trivial. But as for not mentioning Geonosis in EI: probably because Tatooine is a spaceport while Geonosis is an industrial factory. It's like comparing an airport to an electronics factory.
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The Late Knights of Conan O'Brien - Frankenstein...Wasting a minute of your time!
The Late Knights of Conan O'Brien - Frankenstein...Wasting a minute of your time!
While this isn't a thread for this, but a reasonable conclusion is that the Jedi knew that they would blend in on Tatooine, perhaps something that was unlikely to be done on Geonosis (they would stick out from a crowd).Remember, Obi-Wan was looking for a spaceport NOT controlled by the Trade Federation. Geonosis, being an indistrial center, probably had dealings with the Trade Federation even prior to the alliance in Ep II. They wouldnt want to fly into a space port where they are likely to encounter a Trade Federation ship.