Is there anywhere I can find some kind of database on all known stars and their properties (mass, surface temperature, radius, and luminosity)?
I have been looking for some kind of collection of all known stars and their individual respective mass/radius/temperature/and luminosity, can you link me to one if it exists?
My goal is to write an algorithm that creates polynomial functions that calculate a stars temp/lum/radius based on mass. I know there are existing equations, however the ones I have found are more troublesome and imprecise compared to if I could use polynomial functions I create myself.
The Hertzsprung-Russel diagram ( http://upload.wikimedia.org/wikipedia/commons/1/17/Hertzsprung-Russel_StarData.png ) is a great example of representation of what data I need, however it's axes are not constant, so I can not visually gather accurate sample data to deduce any functions.
Edit: Essentially even a large quantity of estimates will suffice. I intend to use this data to generate a semi-realistic galaxy for an MMO I am developing, so it doesn't by any means need to be perfect.
Ok, I would easily settle for a smaller sample. Several thousand or more would suffice. There are functions capable of deriving a specific property from others, for example there are functions that return an estimated radius based on only mass as an input variable. If there is a sample of 10,000 stars with my requested data estimated, that will easily be to satisfaction.
There are probably no more than a couple of hundred stars with reasonably known masses.
If I only need masses estimated to the nearest tenth of a solar mass, would that increase the number of results? By the way thanks for your responses.
No, because those masses will be estimated using the very relationships you are hoping to construct! Or the masses are estimated by using theoretical mass-luminosity relationships. If you are happy with those then why bother to make your own empirical relationships?
Do you just want stars in our own galaxy or stars in other galaxies as well?
Because I am attempting to find my own relationships, but if you say I can not find a large enough sample to make a definitely accurate function, then I'd be willing to use already existing relationships in conjunction with my own analysis to come up with more precise functions. Joshua, Any data is valid, independent of galaxies. I've already done the other research regarding patterns within galaxies, the only variable I am missing is the attributes of the stars themselves. Once I have that I can apply galactic-related patterns.
I see that you have basically solved your problem but in case anyone else needs a legitimate source of star/galaxy data, check out a public database of some survey or other. I would recommend the BOSS one myself, though you may have a hard time getting all the data points you detailed. It would take some work but I imagine you could actually find an excellent catalog of star and galaxy data from this.
I did something similar with the HRD about a week ago. I found that VizieR has a very large database with observations. You can download the tables in different formats (like csv or plain text), but you should first check if the Temperature (mostly log.Tegg) and luminosity (logL) are available. A very detailed one is table V/19. It has those values for 68 clusters, enough to keep you busy for a while!
There are also masses in that list, but you can also create an isochrone yourself, and determine the age of each cluster. Well that was my assignment, and we got pretty close to the expected values for some clusters!
Not sure how much information I can use, but this is definitely the best bank of information I could hope for. Lol enough to keep me busy? I think not :P Im writing a program that will analyze the data for me, designed to create dynamic functions I can use to generate my own galaxy. Basically my program analyzes ratios between different properties throughout the entire range of stellar masses for main sequence stars.
SUre, but you will first need to get the data in the right form, fix bugs, make sure the program works, fix bugs. Et cetera :). If you would draw this by hand you would be out of your mind!
Of course you can search for a different table, with more/better results. It was sufficient for our own little research, and we were happy with the outcome, so no need to do further investigation in searching of different tables
Parsing data is no problem for me. I've even got my own general framework to help with this.
Good luck then!
I would return to the issue of where the masses come from. There are NO measured masses beyond those found in binary systems.
I know, and I am pretty sure that is why there is a question mark in front of the details of the age and mass columns (you cannot measure the age, just like the mass)
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ProfRob 8 years ago
What do you mean by "known stars"? The answer is basically no, there isn't any complete database. Masses in general cannot be found for anything but binary stars. Radii can only be measured for objects in eclipsing binaries or nearby objects. Luminosities rely on distances and these are not known accurately (better than 10%) for more than about 10,000 stars.