Extrasolar, Stars and Exoplanets for Celestia

[gironde]

I open this topic to group your posts on the subject as it was done for Spacerafts for Celestia by Toutatis. Its topic now includes new addons for spacecrafts. I propose the same for Extrasolar (star, exoplanets).

[gironde]

links for :
Kepler-78 system : viewtopic.php?p=141036#p141036
Kepler-90 system : viewtopic.php?p=141051#p141051


to be continued

[Gurren Lagann]

Fomalhaut and its planet + Fomalhaut C

Fomalhaut.rar

(3.33 MiB) Downloaded 607 times

Proxima Centauri b

Proxima Centauri.rar

(3.67 MiB) Downloaded 553 times

Added after 59 seconds:

ups And system

ups And.rar

(1.75 MiB) Downloaded 543 times

[gironde]

LukeCel remarked:

Hey gironde, I noticed that for the orbital parameters of your "Kepler-90.ssc" file you simply used the orbital elements given in exoplanet.eu. This is actually incorrect, as the planets won't pass in front of the star (at least when viewed from the Solar System).

To convert them to a Celestia's ecliptic system, use Grant Hutchinson's Star Orbits Spreadsheet. Simply put in the star's coordinates, the orbital period (in years), eccentricity, inclination, argument of periastron, and epoch (in Besselian years).

I picked up Grant Hutchinson's tools (DCS.xls, panorama.xls, starorbs.xls, and tle.xls). Starorbs.xls actually retrieves data from EllipticalOrbit.
( https://www.classe.cornell.edu/~seb/celestia/hutchison/spreadsheets.html#2)

Here you will find the new .stc files for Kepler-78 and Kepler-90.

Note :
As I had a tool that provided me with calculation, Axis and Angle, for .dsc files, I could control my results and those of Grant. They are the same.
It is very useful for orienting a 3D mesh or 3D billboard for DSO objects

Added after 3 hours 7 minutes:

[gironde]

Fomalhaut C:alf PsA C:LP 876-10


the data from Simbad :
RA 342.018625 # 22h 48m 04.47
Dec -24.36875 # −24° 22′ 07.5

[Gurren Lagann]

Oops... I may didn't read the SIMBAD data back in January... Let me fix this!

Added after 22 minutes 33 seconds:
Fomahaut C fix

[LukeCEL]

Eventually we're going to need a new exoplanet catalogue for Celestia. The one on Github is sadly really outdated, and doesn't include newer discoveries like Proxima b or the TRAPPIST-1 system.

I've built a few definitions for binary stars with exoplanets orbiting around them. These can go in the extrasolar.stc file.

Here's Errai (γ Cep):

Code: Select all

Barycenter "Errai:Arrai:GAM Cep:35 Cep"
{
   RA 354.8368812
   Dec 77.6322743
   Distance 51.7
}

116727 "Errai A:GAM1 Cep:35 Cep A"
{
   OrbitBarycenter "GAM Cep"
   SpectralType "K1IV"
   Radius 3332400
   AppMag 3.22

   EllipticalOrbit {
      SemiMajorAxis 4.56
      Period 67.5
      Eccentricity 0.4112
      Inclination 35.47
      AscendingNode 336.33
      ArgOfPericenter 157.96
      MeanAnomaly 44.77
   }
}

"Errai B:GAM2 Cep:35 Cep B:HIP 116727 B:HD 222404 B:SAO 10818 B"
{
   OrbitBarycenter "GAM Cep"
   SpectralType "M4V"
   AbsMag 11.2

   EllipticalOrbit {
      SemiMajorAxis 15.62
      Period 67.5
      Eccentricity 0.4112
      Inclination 35.47
      AscendingNode 336.33
      ArgOfPericenter 337.96
      MeanAnomaly 44.77
   }
}

Here's Algeiba (γ Leo):

Code: Select all

Barycenter "Algieba:GAM Leo:41 Leo"
{
   RA 154.9931275
   Dec 19.8414852
   Distance 125.6
}

50583 "Algieba A:GAM1 Leo:41 Leo A:HD 89484:SAO 81298"
{
   OrbitBarycenter "GAM Leo"
   SpectralType "K0III"
   AppMag 2.01
   Radius 22188480

   EllipticalOrbit {
      SemiMajorAxis 73
      Period 510.3
      Eccentricity 0.845
      Inclination 121.46
      AscendingNode 106.5
      ArgOfPericenter 201.92
      MeanAnomaly 162.45
   }
}

"Algieba B:GAM2 Leo:41 Leo B:HD 89485:SAO 81299"
{
   OrbitBarycenter "GAM Leo"
   SpectralType "G7III"
   AbsMag 0.6 # guess

   EllipticalOrbit {
      SemiMajorAxis 90
      Period 510.3
      Eccentricity 0.845
      Inclination 121.46
      AscendingNode 106.5
      ArgOfPericenter 21.92
      MeanAnomaly 162.45
   }
}

[gironde]

Yes, extrasolar.stc (star) is getting old and you can not stop making changes inside.
extrasolar.ssc (planets) quickly becomes unsuitable and is compensated by the addons in the 'extras' folder.

I'm sure no one has the same extrasolar.stc and extrasolar.ssc

In addition, the stars carry a multitude of names according to the catalog used (HIP, HD, Tycho, Gaia, ...). It becomes difficult to navigate and you have to be very careful when setting up an addon.

In ssc files for exo-planets, often the planets are named b or c or d, ... When doing a search in Celestia or in an editor, we have in return a multitude of b or c or d, ... without more precision. For my part, I decided to call them the name of the star followed by b separated by a space.

Example for the star "HAT-P-1", the planet is called "HAT-P-1 b" and if a name is given to it, it will be placed in front. example: "Dagon: Fomalhaut A b: 24PsA b" "HD 216956"

But it remains very complicated, there are duplicates, stc forgotten, errors because of the names of the stars. I even found ".ssc modify" which were loaded before before the standard .ssc and thus triggered loading errors.

[Gurren Lagann]

The islands

Ross 128 b - with 4k textures

Ross 128 b.zip

(9.22 MiB) Downloaded 505 times

[LukeCEL]

In addition, the stars carry a multitude of names according to the catalog used (HIP, HD, Tycho, Gaia, ...). It becomes difficult to navigate and you have to be very careful when setting up an addon.

In ssc files for exo-planets, often the planets are named b or c or d, ... When doing a search in Celestia or in an editor, we have in return a multitude of b or c or d, ... without more precision. For my part, I decided to call them the name of the star followed by b separated by a space.

Example for the star "HAT-P-1", the planet is called "HAT-P-1 b" and if a name is given to it, it will be placed in front. example: "Dagon: Fomalhaut A b: 24PsA b" "HD 216956"

Because each star has multiple names, I just name the planet by its letter and drop the star name. That way, when searching in Celestia, you can type "Enter", then "Fomalhaut/b" or "24 PsA/b" or "ALF PsA/b".

[gironde]

That's why we have to keep up to date all the names of stars in starnames.dat and stc.

[gironde]

an addon by Anthony_B_Russo10

viewtopic.php?p=141169#p141169

an catalog of stars HAT-P :
viewtopic.php?p=141187#p141187

[Joey P.]

the largest known stars:

Added after 1 minute 9 seconds:
@Gurren Lagann Proxima Centauri b shouldn't be habitable

[gironde]

Precision on the starnames.dat file

starnames.dat is a table of star names according to different catalogs. The main key is the HIP number without the term 'HIP'.

In stc files, just declare a star by this number and Celestia will take all the following names from the starnames file from the moment this number is contained in starnames. That's why you have to keep the file up to date.

example:
50583 "Algieba To: GAM1 Leo: 41 Leo To: HD 89484: SAO 81298" (stc file)
50583: Algieba To: GAM1 Leo: 41 Leo To: HD 89484: SAO 81298 (starnames file)

in the stc file just write:
50583 {...}
or
Star 50583 {...}


This simplifies the stc file

It seems that we can add TYC numbers:
TYC format 4027-803-1 becomes 18034027

On the other hand, it is better not to declare in starnames a star by its number HIP and further by its number TYC


correction 02-12-2018 : 1008034027

[ghorbanpour]

Hi guys thanks for sharing....

[Fafers_br]

gironde wrote:

It seems that we can add TYC numbers:
TYC format 4027-803-1 becomes 18034027

Yes, we can add TYC numbers, but the format demands 10 digits. The green set of number must have 5 of them (using "zeros" at the left in order to achieve this).
Then, 4027-803-1 becomes 1008034027

[gironde]

Fafers_br, you're right, I forgot the 00

[Gurren Lagann]

But there is a problem!

The maximum TYC designation we can have is TYC 7296-29496-4...

[LukeCEL]

The maximum TYC designation we can have is TYC 7296-29496-4...

That shouldn't be a problem, though. Almost all TYC stars have a designation that ends in 1, 2, or rarely 3. The only TYC stars I could find that are above that are TYC 1327-606-4 and TYC 2907-1276-4, which both still fit.

[gironde]

But there is a problem!

The maximum TYC designation we can have is TYC 7296-29496-4...

perhaps : 4294967296 (always 10 digits)