[Tex/LaTex] How to put a circle around a symbol

Question

I am trying to put \star in a circle so I can use it on my paper. I could not find a proper way to do so. Is there a (simple) way of doing such a custom symbol?

Answer 1

Scaling \bigcirc seems to yield a decent result:

\documentclass{article}
\usepackage{amsmath}
\usepackage{graphicx}

\makeatletter
\newcommand{\ostar}{\mathbin{\mathpalette\make@circled\star}}
\newcommand{\make@circled}[2]{%
  \ooalign{$\m@th#1\smallbigcirc{#1}$\cr\hidewidth$\m@th#1#2$\hidewidth\cr}%
}
\newcommand{\smallbigcirc}[1]{%
  \vcenter{\hbox{\scalebox{0.77778}{$\m@th#1\bigcirc$}}}%
}
\makeatother

\begin{document}

$x\ostar y$

$x\oplus y$

$\oplus\ostar$

\end{document}