I also want to align the second column. The problem is, that there can't be two numbers in one cell Is there a way to align the second column via digits even if there are more decimals? I also used the input-ignore option to ignore the commas
\usepackage{tabular}
\usepackage{siunitx}
\begin{document}
\begin{tabular}{@{}
S[table-format=1.2]
l
@{}}
{Radius} & {Luminosity}\\
0.30 & [-195.728, 213.571] \\
0.000 & [-2465.825, -1234.722] \\
0.648 & [-35.587, 22.432] \\
\end{tabular}
\end{document}