astro.sty

% preamble
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{astro}[2012/06/17 Definitions for astronomy]
% packages
\RequirePackage{amstext}
\newcommand*\rangeto{\textnormal{\hskip.1em\relax--\hskip.1em\relax}}
\RequirePackage[separate-uncertainty=true,range-units=single,
  range-phrase=\rangeto,forbid-literal-units=true]{siunitx}
% common astronomical symbols
\let\sun\odot
\let\bh\bullet
\newcommand*\solarmass{\si{\solarmass}}
\newcommand*\solarluminosity{\si{\solarluminosity}}
% astrophysical units
\DeclareSIUnit\lightspeed{$c$}
\DeclareSIUnit\rydberg{Ry}
\DeclareSIUnit\erg{erg}
\DeclareSIUnit\magnitude{mag}
\DeclareSIUnit\jansky{Jy}
\DeclareSIUnit\gauss{G}
\DeclareSIUnit\h{$h$}
\DeclareSIUnit\hseven{$h$_7}
\DeclareSIUnit\parsec{pc}
\DeclareSIUnit\year{yr}
\DeclareSIUnit\solarluminosity{\ensuremath{L_\sun}}
\DeclareSIUnit\solarmass{\ensuremath{M_\sun}}
\DeclareSIUnit\solarmassinenergy{\ensuremath{M_\sun|c^2}}
\DeclareSIUnit\solarradius{\ensuremath{R_\sun}}
% redeclared units
\DeclareSIUnit\arcsecond{as}
\DeclareSIUnit\astronomicalunit{AU}
\DeclareSIUnit\clight{\ensuremath c}
% additional unit notations
\DeclareRobustCommand\SIfrac{\@ifstar\ast@SIfracplain\ast@SIfracparen}
\newcommand*\ast@SIfracplain[1]{\begingroup\def\@tempa{#1}\ast@@SIfracplain}
\newcommand*\ast@SIfracparen[1]{\begingroup\def\@tempa{#1}\ast@@SIfracparen}
\newcommand*\ast@@SIfracplain[2][]{\frac{\@tempa}{\SI{#1}{#2}}\endgroup}
\newcommand*\ast@@SIfracparen[2][]{\biggl(\ast@@SIfracplain{#1}{#2}\biggr)}
\newcommand*\SIex[2]{#1\,\si{#2}}
% spectroscopic notation
\DeclareRobustCommand\specatom{\@ifstar\ast@atomforbid\ast@atomallow}
\DeclareRobustCommand\specline{\@ifstar\ast@lineforbid\ast@lineallow}
\newcommand*\ast@atomforbid[2]{\textnormal{[\ast@atomallow{#1}{#2}]}}
\newcommand*\ast@atomallow[2]{%
  \textnormal{#1\hskip.1em\relax\textsc{\romannumeral#2}}}
\newcommand*\ast@lineforbid[3]{%
  \textnormal{\ast@atomforbid{#1}{#2}\hskip.2em\relax#3}}
\newcommand*\ast@lineallow[3]{%
  \textnormal{\ast@atomallow{#1}{#2}\hskip.1em\relax#3}}
% term symbol
\DeclareRobustCommand\termsym{\@ifstar\ast@termodd\ast@termeven}
\newcommand*\scripts[5]{\ensuremath{
  ^{#2\vphantom0}_{#3\vphantom0}\hskip-\scriptspace{#1}
  ^{#4\vphantom0}_{#5\vphantom0}}}
\newcommand*\ast@termeven[3]{\scripts{\textup{#2}}{#1}{}{}{#3}}
\newcommand*\ast@termodd[3]{\scripts{\textup{#2}}{#1}{}{\textup o}{#3}}