# 그림:Alpha Centauri relative sizes.png

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## [edit] Summary

Español: Comparación del tamaño y color de las tres estrellas de Alfa Centauri con nuestro sol.

A comparison of the sizes and colors of the stars in the Alpha Centauri system with the Sun.

David Benbennick made this image on January 29, 2005 with the following Metapost program as stars.mp:

    verbatimtex
    \font\foo=cmss9 at 10pt
    \foo
    etex

    sunrad=0.3in;
    alpharad = 1.227*sunrad;
    betarad = 0.865*sunrad;
    proximarad = 0.145*sunrad;
    gap = 0.8*sunrad;

    pair sunpos, alphapos, betapos, proximapos;
    sunpos = (0 + gap + sunrad, 1.9*sunrad);
    alphapos = sunpos + (sunrad + gap + alpharad, 0);
    betapos = alphapos + (alpharad + gap + betarad, 0);
    proximapos = betapos + (betarad + gap + proximarad, 0);

    beginfig(1);

      fill unitsquare xscaled ((xpart proximapos) + proximarad + gap)
        yscaled (2 * (ypart sunpos));

      fill fullcircle scaled (2*sunrad) shifted sunpos
        withcolor (1,0.960,0.949);   % Color is fff1ed
      label.bot(btex Sun etex, sunpos - (0, sunrad)) withcolor white;

      fill fullcircle scaled (2*alpharad)
        shifted alphapos
        withcolor (1,0.960,0.949);
      label.bot(btex $\alpha$ Centauri A etex, alphapos - (0, alpharad))
        withcolor white;

      fill fullcircle scaled (2*betarad)
        shifted betapos
        withcolor (1,0.878,0.737);  % ffe0bc
      label.bot(btex $\alpha$ Centauri B etex, betapos - (0, betarad))
        withcolor white;

      fill fullcircle scaled (2*proximarad)
        shifted proximapos
        withcolor (1,0.752,0.411);  % ffcc6f
      label.bot(btex Proxima etex, proximapos - (0, proximarad))
        withcolor white;

    endfig;
    end;

And I had the following TeX file as stars.tex:

    %&latex
    \documentclass[10pt]{article}
     \usepackage{graphicx}
     \pagestyle{empty}
    \begin{document}
     \includegraphics{stars.1}
    \end{document}

Then I ran

    mpost stars
    tex stars
    dvips -mode ljfzzz -D 1200 stars -o
    convert -density 1200 -chop 99999x99999+6249+3463 -chop 2479x2095 stars.ps stars.png
    pngcrush -reduce -brute -l 9 stars.png stars.crush.png

stars.crush.png was the final output file.

(Apparently it's non-trivial to get dvips to use a given resolution. I would have preferred to use 1600 dpi, but dvips didn't already have a "printer" at that resolution. ljfzzz, at 1200, was the best I could find.)

I, the author of this work, hereby publish it under the following licenses:

| Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

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## [edit] References

- I took the star colors from [1], which indicates they're only approximate. Apparently there are inherent difficulties in representing a star's color on a computer monitor.
- I took the star radii from [2].

## 그림 링크

다음 문서들이 이 그림을 사용하고 있습니다:

- 켄타우루스자리 프록시마
- 켄타우루스자리 알파

원본 주소 ‘http://ko.wikipedia.org../../../a/l/p/%EA%B7%B8%EB%A6%BC%7EAlpha_Centauri_relative_sizes.png_806d.html’

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