- #1

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## Main Question or Discussion Point

I have a data set of 120k star systems that I'd like to import into a project, and, while it has a lot of useful infomation, I'd like to display these stars in a visual fashion. This means that I need to figure out the radius, when zoomed into the star system, and its mass, to simulate objects in orbit. If I have the radius, I can appoximate its mass. I have a basic idea of how to color them.

The data set I've chosen gives me the Spectral Class, the B-V Color Index, and the Luminosity of each star, and I'm hoping that's enough to plug into some math out there to approximate the radius and/or mass. When I checked out this data, I found some weird spectral codes outside of the typical, established OBAFGKM set, such as D, C, S, R, W, N, and P. This code will basically determine the Temperature, as I understand it, thus determining the Radius, but I'm not sure where these fit in. "D" is a white dwarf, I think, for example, and "C" is a Carbon star, but I don't have any temperature info on those or the others.

My main question is this: how do I calculate the stars' radii and/or mass from the data I have?

The data set I'm looking at is here:

http://astronexus.com/node/34

The description of the data headers is here:

https://github.com/astronexus/HYG-Database/blob/master/README.md

This is the breakdown of spectral classes:

32182 K

25605 F

22798 G

18697 A

10413 B

5831 M

3050 <no data>

282 D

264 O

162 C

102 S

89 R

74 W

61 N

4 P

The data set I've chosen gives me the Spectral Class, the B-V Color Index, and the Luminosity of each star, and I'm hoping that's enough to plug into some math out there to approximate the radius and/or mass. When I checked out this data, I found some weird spectral codes outside of the typical, established OBAFGKM set, such as D, C, S, R, W, N, and P. This code will basically determine the Temperature, as I understand it, thus determining the Radius, but I'm not sure where these fit in. "D" is a white dwarf, I think, for example, and "C" is a Carbon star, but I don't have any temperature info on those or the others.

My main question is this: how do I calculate the stars' radii and/or mass from the data I have?

The data set I'm looking at is here:

http://astronexus.com/node/34

The description of the data headers is here:

https://github.com/astronexus/HYG-Database/blob/master/README.md

This is the breakdown of spectral classes:

32182 K

25605 F

22798 G

18697 A

10413 B

5831 M

3050 <no data>

282 D

264 O

162 C

102 S

89 R

74 W

61 N

4 P