Stellar Information

[robject]

Or: F7 V BD || M3 V

Perhaps :
| = Near
and
|| = Far

I like that!

In monospace font, | and || are visually confusing with I and II. I'll try / and // and see what that's like...

 

[Spinward Flow]

I'll try / and // and see what that's like...

Actually, if you're going to do that, might as well help yourself downstream.
/# = stellar companion and the companion's orbit number (so /3 for example) with /- being contact
// = far companion as previously specified

Regina (example)

F7V /-BD //M3V

F7 V primary "Lusor"
BD companion "Speck" in contact with Lusor (so orbit 0 remains open for a planet)
M3 V far companion "Darida"

 

[willtron3030]

That could work.

IIRC, the system that was being considered was using [brackets], (parentheses), and {braces} for [Close], Near, (Far) and {Extreme} Companions, with an asterisk (*) on the primary (or primary group) of the main world. (A Near Companion had no punctuation notations).

So your example above could have been:

[A1 V M5 V]*, M2 V, M1 V, M1 V, (A2 V)

If the two M1 V stars were themselves a close orbiting pair, then:
[A1 V M5 V]*, M2 V, [M1 V M1 V], (A2 V)

If the M1 V pair were orbiting the Far Companion:
[A1 V M5 V]*, M2 V, (A2 V [M1 V M1 V])

I've been using a nested JSON format that includes average distance and eccentricity. I need to add a function to format system configuration in this representation; it's a really useful overview.

 

[ovka]

So I guess there are almost as many ways to interpret the star lists are there are people on these boards.

I *do* like the F7V /-BD //M3V notation for Regina, though I think adding this to the existing T5SS data would be cumbersome.

Any thoughts on formulas for stellar radii? It isn't so bad for main sequence (luminosity class V) stars, an approximation of that data is available in several different places on the internet (though each is a bit different ), but data for stars with luminosity classes Ia, Ib, II, III, IV, VI, and D is harder to find. From what I have been reading, this is because there is much more variability than with main sequence stars.

It seems like a formula for HZ should be easier to come by.

For both of these (radius and habitable zone), I really just want to come up with 1. average values, given a particular stellar classification, and 2. ways to make them a little variable by slightly adjusting some of the variables (temp, luminosity, mass, etc.).

Cheers,

Baron Ovka

 

[robject]

Any thoughts on formulas for stellar radii?

It seems like a formula for HZ should be easier to come by.

For both of these (radius and habitable zone), I really just want to come up with 1. average values, given a particular stellar classification, and 2. ways to make them a little variable by slightly adjusting some of the variables (temp, luminosity, mass, etc.).

Book 6: Scouts is good enough for me.

But, there's one other thing I've wanted. I want to design a slide rule-like thing that goes from star class and size to 100D distance.

I'd like to use "Orbit Number" as the 100D point, which is kind of like a logarithmic scale (ha!).

Orbit #    Class     Size
-------    -----     ----
    13
 
    12
 
    11      M5
        
    10     
        
    9       K5

    8       G5       II
            F5
    7

 

[Spinward Flow]

I *do* like the F7V /-BD //M3V notation for Regina

So do I, but it doesn't have to be formatted that way explicitly.
There are other ways to accomplish the same goal. I just wanted to illustrate one method for doing so using the current context. I'm sure there are alternatives that would be more efficient than what I outlined.

The concept is the important part.
Implementation can be subject to all kinds of tweaks to make life easier in the necessary programming downstream to interpret the data consistently.

 

[willtron3030]

Any thoughts on formulas for stellar radii?

Radius and luminosity of a main sequence star can be approximated with:

The exponents do actually vary a little with mass, so I am grossly oversimplifying. There are other factors such as metallicity that affect the calculations.

You can then calculate the temperature from the radius and luminosity.


Conversely, if you know the temperature and luminosity, you can calculate radius:


Mass, Luminosity, Radius, and Temperature are all expressed here in units where 1 is the value for Sol.

A well done but similarly oversimplified overview of the calculations can be found on YouTube [LINK]

 

[tjoneslo]

Any thoughts on formulas for stellar radii? It isn't so bad for main sequence (luminosity class V) stars, an approximation of that data is available in several different places on the internet (though each is a bit different ), but data for stars with luminosity classes Ia, Ib, II, III, IV, VI, and D is harder to find. From what I have been reading, this is because there is much more variability than with main sequence stars.

I will point out this information is in the wiki. We went through all the star types and entered the data

https://wiki.travellerrpg.com/Special:CargoTables/StarData -> This is the table of data which you are free to copy as needed.

In the articles about the worlds we expand this into a large table with this information:

https://wiki.travellerrpg.com/Regina_(world)#Trinary_Solar_System

Since the data for exactly where these stars are in the system isn't included in the Traveller Map/T5 data sets we can't include it in the wiki. But if it were there, it can be included easily.

 

[willtron3030]

I will point out this information is in the wiki. We went through all the star types and entered the data

Excellent. One more set for me to compare the results of my code to. Thanks for the link!

 

[tjoneslo]

One more set for me to compare the results of my code to.

If you find differences, please post a note in the Traveller Wiki forum below or in the Watercooler forum in the wiki itself. Having another set or eyes on the data makes it better for everyone.

 

[bookwyrm]

didn't know that was there. I'll be looking at that and taking notes.

I also have been doing a little research on this subject, so I have a big smile right now. I second the thanks for the link!

also, for diameter, safe distance, and inner/outer habit zone, is that in millions of kilometers?

 

[Vargr Breath]

Stars, we don't need no stinking Stars, it's 1977 just roll up your world stats and move along.

 

[willtron3030]

for diameter, safe distance, and inner/outer habit zone, is that in millions of kilometers?

Not sure about diameter, but the other three are in Astronomical Units (AU). 1AU is the mean distance from Earth to Sol, 149,597,870.7 km, or a little over 499 light seconds.

 

[tjoneslo]

didn't know that was there. I'll be looking at that and taking notes.

I also have been doing a little research on this subject, so I have a big smile right now. I second the thanks for the link!

also, for diameter, safe distance, and inner/outer habit zone, is that in millions of kilometers?

https://wiki.travellerrpg.com/Star/data this table has the units for the values. All distances are in AU. Which I think are 150Mkm, and not the more precise 149.597Mkm

 

[ovka]

I will point out this information is in the wiki. We went through all the star types and entered the data

https://wiki.travellerrpg.com/Special:CargoTables/StarData -> This is the table of data which you are free to copy as needed.

Perfect! This looks like exactly what I need.

Cheers,

Baron Ovka

 

[GypsyComet]

The "Copyright issue" has one simpler solution, since my notation, *published* in Swordy's magazine in the Far Frontiers articles, predates that other guy's by a few years. It's rarely that easy, though. My version also only addresses the variations possible in the system generation of CT, MT, and TNE.