How do I input the symbol for Solar Mass?

Question

I need to put stellar mass data in units of Solar Mass, and I tried the M_{\odot}, but the console shows:

! missing $ inserted error.

I don't know what is wrong. Please help me out

You can't use subscripts in text mode. Either use $M_\odot$ or M\textsubscript{$\odot$}. — John Kormylo, May 16 '17 at 13:01
I suggest reading https://en.wikibooks.org/wiki/LaTeX/Mathematics ... worth the time — Rmano, May 16 '17 at 13:03
@Rmano NOOOO! Not the wikibook. It's crap. Read LaTeX and Friends instead! — Henri Menke, May 17 '17 at 02:13
I'm voting to close this question because it was solved in the comments. — Stefan Pinnow, May 11 '18 at 04:15
@Troy the question is clearly about TeX (not off-topic), it is clear enough that although there's no MWE the problem can be recognised (not unclear), and even has an upvoted answer - why close as off-topic in the first place? Solved in comments is not a valid close reason, something like problem was just a typo which was identified in the comments can be but that doesn't strike me as the case here. Perhaps this should be closed as a dupe but that's a whole different thing. — Dai Bowen, May 11 '18 at 09:54
@Hansatanu Roy: Please consider accepting my answer if it satisfies you. — lblb, Dec 21 '18 at 12:13

lblb · Answer 1 · 2021-02-10T07:54:56.937

23

TeX complains with missing $ inserted because of the underscore. _ is a special character dedicated for subscripts, which require math mode.

My first example is all math mode, the second one is typesetting the M in upright text mode, the third uses text mode for the subscript. Choose for yourself whether the solar mass should be typeset in math italic—as a variable—or upright—as having a defined meaning.

\documentclass{article}
\begin{document}
(M_\odot)
or
(\textup{M}_\odot)
or
M\textsubscript{(\odot)}
\end{document}

edited Feb 10 '21 at 07:54

answered May 22 '17 at 12:32

lblb

3,454

1

This is a bit old but I must comment on one point: denoting _ as active character is misleading. TeX reserves this name to chars with category code 13. The underscore is a subscript character (category code 8). In your answer I would rather use "special character" to avoid issues. – campa Dec 05 '20 at 09:23

Davislor · Answer 2 · 2020-12-05T03:33:49.567

In Unicode, the symbol you want is U+2609, and can be loaded from any font that contains it using fontspec. Here is an example using DejaVu Sans, and the output with LuaLaTeX.

\documentclass{article}
\tracinglostchars=2
\usepackage{fontspec}
\newfontfamily\symbolfont{DejaVu Sans}[Scale=MatchUppercase]
\newcommand\astrosun{{\symbolfont\symbol{"2609}}}
\newcommand\solarmass{\ensuremath{\mathrm{M}_{\textnormal{\astrosun}}}}
\pagestyle{empty} % Suppress page numbering.
\begin{document}
Solar mass is denoted {\solarmass}.
\end{document}

How do I input the symbol for Solar Mass?

2 Answers2