Is this enough info to construct a binary?

[Hungry4info]

Again, sorry for the delay.

How do you get it to show those happy, sparkly orbits of the stars?

To view orbits, press the 'o' button.

Can you make that third star shine on a planet (ala specular power and all that shiny stuff

An object with a specular map will have specular effects from both stars. If you would like an picture to elabourate, let me know.

Code: Select all

 "Hadar I" "BET Cen"

Will make it orbit the primary barycenter.

Code: Select all

 "Hadar I" "BET Cen A"

Will make it orbit the AA / AB barycenter.

When you had it set to orbit Hadar, it orbited only one star, BET Cen A. This is because the original STC in your data folder declares star HIP 68702 as Hadar. In this newer STC, only BET Cen AA is defined as HIP 68702. (The number before the name gives Celestia an HIP number so you can override Celestia's default stars, the numbers are not required, so non HIP-stars can be added). Since you set it up for the planet to orbit Hadar, Celestia recognized Hadar as HIP 68702, which Celestia recognized to be BET Cen AA in our STC here. To fix this, you can either erase the number (68702) before "Bet Cen AA" and place it right before "BET Cen", or you can modify the SSC file to place the planet in oribt of "Bet Cen". This shall make it orbit the barycenter of the system. Furthermore, if you give it the exact same orbital parameters of BET Cen B, then add or subtract (360/6) = 60 degrees from it's ArgOfPericenter (or in the case of your SSC, LongOfPericenter), that'll place the planet in the Lagrange point you wish.

Celestia does not supply temperatures for planets orbiting a barycenter, so it will give it 0 K. I guess the best thing to do is give it an Earth-like map or something to let people know it's habitable.

I may need help, but I'm going to do my best to do it on my own to show I've learned something at all from our chat. =)

I'll be here to help . At first, I really wasn't good at this and had to ask for help also.

Regulus, eh? Missing orbital data can be worked around with mathematics. For example, if you know the seperation and their masses, you can do a bit of math to poke at it's orbital period. Whether or not you want to ignore the orbital periods of the stars is up to you. I have some stars that take a few tens of thousands of years to complete an orbit, but have included them for completeness.

[Slartibartfast]

Putting this in the SSC file results in a missing planet:

Code: Select all

"Hadar I" "BET Cen"

What am I doing wrong?

Regulus A = 4.4 x mass of the sun
Regulus B1 = 0.77
Regulus B2 = 0.2

A is 4205AU from B1 & B2 (orbit takes 130,000 years)
B1 & B2 are seperated by 92.7 AU or 98.9 AU, taking 1000 or 2000 years depending on your source.

So, what's the formula/formulae? =)

[Hungry4info]

What am I doing wrong?

I don't know, honestly. Putting in what you wrote works for me. Could you please post your whole SSC?

And for Regulus, you already have enough information to construct the basic oribtal parameters. Without knowing the LongOfPeri, Ascending Node, and such, the system will not be in the right orientation though, nor will it have the proper eccentricity unless you can find that somewhere.

[Slartibartfast]

It's a big SSC file, but here goes. =)

Code: Select all

# Data for the Celestine Planets

"Prime" "Bellatrix"
{
   Texture "4kbellatrix.png"
   Color [ 0.75 0.75 1.0 ]
   HazeColor [ 0.6 1 0.75 ]
   HazeDensity 0.3

   Radius 31900 # equatorial
   OverlayTexture "jupiterclouds.png"
   Oblateness 0.0649

   EllipticalOrbit
   {
   Period          216.5025
   SemiMajorAxis    77.0
   Eccentricity      0.0484
   Inclination       1.3053
   AscendingNode   100.556
   LongOfPericenter 14.7539
        MeanLongitude    34.404
   }

       Atmosphere {
      Height 300
      Lower [ 0.7 0.6 0.5 ]
      Upper [ 0.5 0.45 0.4 ]
      Sky [ 0.8 0.8 0.5 ]
            Sunset [ 1.0 0.6 0.2 ]
            CloudHeight 20
      CloudSpeed 80000
      CloudMap "jupiterclouds.*"
   }

   RotationPeriod         9.927953 # System II (for GRS)
   # RotationPeriod       9.92425  # System III (radio

emissions)
   Obliquity              2.222461 # 1.82246 # 2.22246
   EquatorAscendingNode -22.203    # -1.87785 # -22.203
   RotationOffset        12        # for correct location of

GRS
                                   # (equal to 101 minus

current W longitude of GRS)
   # RotationOffset     305.40     # correct System III prime

meridian

   Albedo 0.95
}


"Bellatrix A" "Bellatrix/Prime"
{
   Texture "bellatria.*"
   SpecularColor [ 0.5 0.5 0.55 ]
   SpecularPower 25.0
   Radius   5576.647
   OverlayTexture "sheliakhclouds.png"
   EllipticalOrbit
   {
   Epoch 2443000.00038375
   Period        10.63
   SemiMajorAxis  1111000
   Eccentricity   0.0015
   Inclination    0.00095
   AscendingNode    119.841
   LongOfPericenter 188.831
   MeanLongitude    121.206
   }

   Obliquity        0.1
   EquatorAscendingNode   161.6
   RotationOffset      262.1

   Albedo         0.30
}

AltSurface "limit of knowledge" "Sol/Jupiter/Ganymede"
{
   Texture "ganymede.*"
   OverlayTexture "ganymede-lok-mask.png"
}

"Sheliakh" "Bellatrix/Prime"
{
   Texture "sheliakh.*"
   Radius   4327.576
   OverlayTexture "sheliakhclouds.png"
   BumpMap "sheliakhbump.jpg"

   EllipticalOrbit
   {
   Epoch 2443000.00038375
   Period        22.364
   SemiMajorAxis  1825900
   Eccentricity   0.007
   Inclination    0.004
   AscendingNode    323.265
   LongOfPericenter 335.933
   MeanLongitude     85.091
   }

   Obliquity        0.4
   EquatorAscendingNode   160.6
   RotationOffset      120.1

   Albedo         0.31
}

AltSurface "limit of knowledge" "Sol/Jupiter/Callisto"
{
   Texture "callisto.*"
   OverlayTexture "callisto-lok-mask.png"
}
"Hunrath" "Bellatrix/Prime"
{
   Texture       "prometheus.*"
   Mesh      "prometheus.cmod"
   Radius    74 # maximum semi-axis
   MeshCenter [ 0.75 -2.68 1.064 ]

   EllipticalOrbit
   {
   Epoch      2453005.5   # 2004 Jan 1 00:00UT
   Period      0.6130
   SemiMajorAxis   139380
   Eccentricity   0.0023
   Inclination   0.0056
   AscendingNode   226.1099
   LongOfPericenter 23.3280
   MeanLongitude   266.2144
   }

   RotationEpoch      2453005.5   # 2004 Jan 1 00:00UT
   RotationOffset     86

   Albedo 0.6
}

"Vor" "Bellatrix/Prime"
{
   Texture       "asteroid.jpg"
   Mesh      "pandora.cmod"
   Radius      57 # maximum semi-axis
   MeshCenter [ 0.692 -1.454 -0.422 ]

   EllipticalOrbit
   {
   Epoch      2453005.5   # 2004 Jan 1 00:00UT
   Period      0.6285
   SemiMajorAxis   141710
   Eccentricity   0.0042
   Inclination   0.0522
   AscendingNode   290.0163
   LongOfPericenter 10.4899
   MeanLongitude   212.6961     
   }

   RotationEpoch      2453005.5   # 2004 Jan 1 00:00UT
   RotationOffset          33

   Albedo 0.9
}
"Esh A" "Zubeneschamali"
{
   Texture "ZE.*"
   # Texture "mars8k.dds"
   BumpMap "marsbump.*"
   BumpHeight 2.5
   Color   [ 1 0.75 0.7 ]
   HazeColor [ 1 1 1 ]
   HazeDensity 0.45
   Radius 3396 # equatorial
   # Oblateness 0.0069

   Atmosphere {
      Height 30
      Lower [ 0.8 0.6 0.6 ]
      Upper [ 0.7 0.3 0.3 ]
      Sky [ 0.83 0.75 0.65 ]
                Sunset [ 0.7 0.7 0.8 ]
                # Slightly bluish sunset, as seen in true color

pictures
                # from Pathfinder
   }

   EllipticalOrbit
   {
   Period           19.489
   SemiMajorAxis    11.1
   Eccentricity      0.0934
   Inclination       1.8506
   AscendingNode     49.479
   LongOfPericenter 336.041
        MeanLongitude    355.453
   }

   RotationPeriod        24.622962
   Obliquity             26.72
   EquatorAscendingNode    82.91
   RotationOffset       136.005

   Albedo            0.75
}
"Hadar I" "BET Cen"
{
   Texture "NewHadar.*"
   
   Color [ 0.85 0.85 1.0 ]
   SpecularColor [ 0.5 0.5 0.55 ]
   SpecularPower 25.0
   HazeColor [ 1 1 1 ]
   HazeDensity 0.3
   Radius 6897.153  # equatorial
   # Oblateness 0.0034
   OverlayTexture "sheliakhclouds.png"

   Atmosphere {
      Height 60
      Lower [ 0.43 0.52 0.65 ]
      Upper [ 0.26 0.47 0.84 ]
      Sky [ 0.40 0.6 1.0 ]
      Sunset [ 1.0 0.6 0.2 ]
      # Sunset [ 0.3 1.0 0.5 ]
      CloudHeight 7
      CloudSpeed 65
   }

   EllipticalOrbit {   
      Period          440.2615
      SemiMajorAxis   110.0
      Eccentricity      0.0167
      Inclination       0.0001
      AscendingNode   348.739
      LongOfPericenter 102.947
           MeanLongitude   100.464
   }

   RotationPeriod   28.63 # day hours
   Obliquity        0.45
   RotationOffset   280.5    # offset at default epoch J2000

   Albedo            0.50
}
"Rasalas A" "Rasalas"
{
   Texture "Rasalas.*"
   SpecularColor [ 0.5 0.5 0.55 ]
   SpecularPower 35.0
   Radius 6590.935 # equatorial
   # Oblateness 0.0034
   OverlayTexture "sheliakhclouds.png"

   Atmosphere {
      Height 60
      Lower [ 0.43 0.52 0.65 ]
      Upper [ 0.26 0.47 0.84 ]
      Sky [ 0.40 0.6 1.0 ]
      Sunset [ 1.0 0.6 0.2 ]
      # Sunset [ 0.3 1.0 0.5 ]
      CloudHeight 7
      CloudSpeed 65
   }

   EllipticalOrbit {   
      Period          13.55631
      SemiMajorAxis   170.0
      Eccentricity      0.0167
      Inclination       0.0001
      AscendingNode   348.739
      LongOfPericenter 102.947
           MeanLongitude   100.464
   }

   RotationPeriod   307.2 # day hours
   Obliquity        0.45
   RotationOffset   280.5    # offset at default epoch J2000

   Albedo            0.00000005
}
"Regulus A" "Regulus"
{
   Texture "Regulus.*"
   SpecularColor [ 0.5 0.5 0.55 ]
   SpecularPower 35.0
   Radius 9459.28 # equatorial
   # Oblateness 0.0034
   OverlayTexture "sheliakhclouds.png"

   Atmosphere {
      Height 60
      Lower [ 0.43 0.52 0.65 ]
      Upper [ 0.26 0.47 0.84 ]
      Sky [ 0.40 0.6 1.0 ]
      Sunset [ 1.0 0.6 0.2 ]
      # Sunset [ 0.3 1.0 0.5 ]
      CloudHeight 7
      CloudSpeed 65
   }

   EllipticalOrbit {   
      Period          0.555159369
      SemiMajorAxis     0.556776
      Eccentricity      0.0167
      Inclination       0.0001
      AscendingNode   348.739
      LongOfPericenter 102.947
           MeanLongitude   100.464
   }

   RotationPeriod   307.2 # day hours
   Obliquity        0.45
   RotationOffset   280.5    # offset at default epoch J2000

   Albedo            0.9992
}
"Mulu-Lizi A" "Mulu-lizi"
{
   Texture "Mulu-Lizi.*"
   SpecularColor [ 0.5 0.5 0.55 ]
   SpecularPower 65.0
   Radius 8138.684 # equatorial
   # Oblateness 0.0034
   OverlayTexture "sheliakhclouds.png"

   Atmosphere {
      Height 60
      Lower [ 0.43 0.52 0.65 ]
      Upper [ 0.26 0.47 0.84 ]
      Sky [ 0.40 0.6 1.0 ]
      Sunset [ 1.0 0.6 0.2 ]
      # Sunset [ 0.3 1.0 0.5 ]
      CloudHeight 7
      CloudSpeed 65
   }

   EllipticalOrbit {   
      Period          13.03757
      SemiMajorAxis     9.060905
      Eccentricity      0.0167
      Inclination       0.0001
      AscendingNode   348.739
      LongOfPericenter 102.947
           MeanLongitude   100.464
   }

   RotationPeriod   17.9 # day hours
   Obliquity        0.45
   RotationOffset   280.5    # offset at default epoch J2000

   Albedo            0.45
}


With these settings, the planet Hadar I disappears/does not register.

[Slartibartfast]

Oh, back to the RA issue. I figured out the basic idea, but without your input data, I can't figure out if I'm right. What formula did you use to get degrees from d h m s ? Does the same thing work for converting Dec to a decimal?

EDIT
Nevermind... I found the following website that does it for me! =)

https://www.swift.psu.edu/secure/toop/convert.htm

[Hungry4info]

Well, I tried your STC and it all works for me



One little note, you may want to erase the extraneous comments from your STC such as "Slightly bluish From pathfinder" and all that. They don't contribute to your STC.

[Slartibartfast]

I found the problem. The planet is there, but if you target the star Hadar and go there, then try to target Hadar I, you can't see it in the target list. I'm still working on Regulus... looks like it might take a while... I'm having to sort out each stat, but I'm learning! =)

[Hungry4info]

Ah, I'm glad to hear that. Again, I'll be happy to continue assisting you. I'll probably be gone for the rest of the day though (church services).

[Slartibartfast]

Looking back, I'm having a problem with the following math.

To solve for less, even, numbers, you can set it up like this.

x / y = 6.51282051282
x + y = 110

where x is the semi-major axis of the less massive star, and y is the semi-major axis of the more massive star. The more massive star or barycenter in this case, always has a smaller semi-major axis because it is not moved as much by the less massive star. You can solve this as any sort of system of equation.
Rearrange -> y=110 - x
Substitute -> x / (100 - x) = 6.51282051282

After solving, you should obtain 86.6894197952 AU for x.
Since x + y = 110, and x = 86.6894197952,
86.6894197952 + y = 100.
y = 23.3105802048 AU.

When I solve for y, I get 14.64164 (which makes x=95.35836).

x=110-y
110-y/y = 6.51282051282
110-y= 6.51282051282y
110= 6.51282051282y+y
110= 7.51282051282y
y= 110/7.51282051282= 14.64164

Am I nuts?

[Slartibartfast]

Can you look over these results? I tried using the formulae you gave me for determining the SemiMajoraxis for both (A&B) and (B1&B2). Did I insert the right numbers in the right places for the numbers I did not mean to be arbitrary? It is my intention to have the name Regulus apply to the K1V, hence the juggling of names.

Code: Select all

# Regulus A/B1-B2
Barycenter "ALF Leo"
{
RA         152.0958
Dec        11.9667
Distance   77.500593965 # using SIMBAD distance, rather than the

paper.
}

   Barycenter "ALF Leo A"
   {
      OrbitBarycenter "ALF Leo"

      EllipticalOrbit {
         Period          130000
         SemiMajorAxis   3445.44
         Eccentricity    0.0 # Unknown.
         Inclination   0   # Unknown.
         AscendingNode   180 # Unknown.
         ArgOfPericenter 0   # Unknown.
      }
   }


 
      "ALF Leo B1:Regulus"
      {
      OrbitBarycenter "ALF Leo A"
      SpectralType "K1V"
      AppMag  8 #Visual Magnitude, is this the same thing?


          EllipticalOrbit
                   {       
             Period  1000.0   
            SemiMajorAxis  19.58763   
            Eccentricity  0.819   #Arbitrary   
             Inclination  172.66  #Arbitrary     
             AscendingNode  31.31       #Arbitrary
             ArgOfPericenter  318.16       #Arbitrary
             MeanAnomaly  40.89       #Arbitrary
         }       

      }

      "ALF Leo B2:Venant"
      {
      OrbitBarycenter "ALF Leo A"
      SpectralType "M3V"
      AppMag 13.0 #Visual Magnitude, is this the same thing?


           EllipticalOrbit
                   {       
             Period  1000.0   
             SemiMajorAxis  75.41237   
             Eccentricity  0.819   #Arbitrary   
             Inclination  172.66       #Arbitrary
             AscendingNode  31.31       #Arbitrary
             ArgOfPericenter  138.16       #Arbitrary
            MeanAnomaly  40.89       #Arbitrary
         }
      }

   49669 "ALF Leo A:Kalb"
   {
   OrbitBarycenter "ALF Leo"
   SpectralType "B7V"
   AppMag 1.36 #Visual Magnitude, is this the same thing?


       EllipticalOrbit
                   {       
         Period  130000
         SemiMajorAxis   759.56
         Eccentricity    0 # Unknown.
         Inclination     0 # Unknown.
         AscendingNode   0 # Unknown.
         ArgOfPericenter 0 # Unknown.
         MeanAnomaly     0 # Unknown.
       }
   }


For some reason the new stars, etc. are not showing up in Celestia. =( Actually they show up if I put them in a STC by themselves, but if I include them with my Hadar stars, they don't show up. Wierdness.

[Hungry4info]

You have both your Barycenter and primary star named ALF Cen A, I don't know if that will affect anything, but it certainly is rather inconsistant. And yes, AppMag is the same as Visual magnitude, as the "App" is "apparent". Absolute magnitude is written AbsMag.

Code: Select all

Distance   77.500593965 # using SIMBAD distance, rather than the

paper.
}


If "paper" is on a line of it's own in your STC, it will mess it up.
Delete Extraneous Comments.
[/b]

[Slartibartfast]

Thanks for all the help. =) I trimmed the extraneous stuff Everything works fine if I don't combine my STCs, so I'll just leave them separate. Was my math right earlier? If not, what was I doing wrong?

When I solve for y, I get 14.64164 (which makes x=95.35836).

x=110-y
110-y/y = 6.51282051282
110-y= 6.51282051282y
110= 6.51282051282y+y
110= 7.51282051282y
y= 110/7.51282051282= 14.64164

Am I nuts?

[Hungry4info]

Yes, sorry, your mathematics is correct. I put it into my calculator wrong. I have an Excel document, within which I have written a "binary orbital solution solver" where you plug in masses and seperation and it spits out the semi-major axies. It concurred with you.

My apologies.

Am I nuts?

No, no, that's my job. I am Stupidity's Flagship.

[Slartibartfast]

No, no, that's my job. I am Stupidity's Flagship.

No, that one goes to my former student who said, and I quote, "I'm like the Tin Man, sir, I don't have a brain!"

That was the most eloquent case-in-point argument I'd ever had. I conceded the point immediately.

I don't suppose I could get a copy of your spread-sheet?

[BobHegwood]

No, no, that's my job. I am Stupidity's Flagship.

Uh, if you don't mind here folks, I have worked very hard to get
and to maintain my reputation as the Celestia preferred stupidity
guy. I am, after all, Brain-Dead Bob.

Just ask Doctor Schrempp...

[Hungry4info]

I don't suppose I could get a copy of your spread-sheet?

Yeah, I'll make it publically avalible. I don't really know how to do that yet... but I'll find out when I get home.

Uh, if you don't mind here folks, I have worked very hard to get and to maintain my reputation as the Celestia preferred stupidity guy.

Very well, very well.

[ajtribick]

I do not get the numbers you do for the orbit of the Aa/Ab pair of BET Cen.

Using the interferometric orbit in the Davis et al. paper, and the parallax given there of 9.77 mas (distance = 333.84 light years), I get a different set of elements, using Grant's spreadsheet.

I've positioned Star B according to the values in the CCDM (access from SIMBAD page), but it says the measurement is from 1960. Hopefully I haven't done something stupid like reverse the position angle. I've guessed the mass of star C as 6 solar masses based on its visual magnitude, but this is a fairly rough guess. I haven't tried to implement orbital motion, because as far as I am aware it isn't known. Also not sure if BET Cen Aa/Ab and BET Cen B are actually associated...

Also I'm doing this on the operating system where I haven't got Celestia installed, so I don't know if the following actually does anything sensible.

EDIT: removed code generated using bad mathematics. See below.

[ajtribick]

BTW regarding the earlier discussion of Trojan points - even for circular orbits the Trojan point is only stable if the mass ratio m/M<0.04 where M and m are the primary and secondary masses respectively.

This condition is not satisfied in the Beta Centauri system where the stars have fairly equal masses, so even if the stars were in circular orbits (in fact, the system is highly eccentric), the Trojan points would be unstable.

In fact the mass ratio of binary stars is usually not extreme enough to make the Trojan points stable (plus the fact that the orbits are usually eccentric doesn't help).

[Slartibartfast]

I get a different set of elements, using Grant's spreadsheet.

Who is Grant and how do I get my hands on his spreadsheet? (I love spreadsheets).

I've positioned Star B according to the values in the CCDM (access from SIMBAD page)

How/where did you find this? I couldn't find Star B.. but I'm ignorant in the ways of SIMBAD.

I've guessed the mass of star C as 6 solar masses based on its visual magnitude, but this is a fairly rough guess.

I got these numbers from Jim Kaler's website plus some math:

Star's AA AB B
Spectral Class B1III B1III B8V
Luminosity 15,500(sun) 15,500(sun) 1,500(sun)
Mass 12.7(sun) 12.7(sun) 3.9(sun)
Diameter 8.2(sun) 8.2(sun) 3.15(sun)

[Slartibartfast]

Ack, it posted the above reply before I was done... could hitting the space bar too many times trigger that? Wierd! Anyway.. on with my reply:

I do not get the numbers you do for the orbit of the Aa/Ab pair of BET Cen...... I get a different set of elements

Imagine yourself sitting at a table with two Florentines that are debating the meaning of the word "tempo" and they keep speaking Italian with each other during the conversation. You don't speak a lick of Italian. How do you draw any conclusions? My best idea is to ask them to explain why they're right and the other guy is wrong... in English.

So. I know it's my fault that I'm so ignorant, so late in life, but if you have the time and don't mind spending it, could I ask you to explain where things went wrong/ the fault in the mathematics/logic as if I were a third-grader? Because I'm clueless. It'd really help, and I'd REALLY appreciate it!

Thanks!
Slartibartfast