Image:Alpha Centauri relative sizes.png

Summary

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

A vector version of this image (SVG) is available. It should be used in place of this raster image when superior. Image:Alpha Centauri relative sizes.png    Image:Alpha Centauri relative sizes.svg For more information about vector graphics, read about Commons transition to SVG. There is also information about MediaWiki's support of SVG images. Deutsch | English | Español | Français | Galego | עברית | Magyar | Italiano | 日本語 | 한국어 | Lietuvių | Polski | Português | Русский | Српски / Srpski | Українська | +/-

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);   % Colour 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.)

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References

• I took the star colors from , which indicates they're only approximate. Apparently there are inherent difficulties in representing a star's colour on a computer monitor.
• I took the star radii from .