asterisk in subscript

hi,

i am trying to label a plot axis with the equivalent of the latex $n_*$.
i initially tried

expression(paste(italic(n)["*"]))

but this made the * absolutely tiny and centred about midway wrt the n.
then

expression(paste(italic(n)[textstyle("*")]))

made the * about the right size but now it looks more like a superscript
than a subscript.

does anyone have an idea of how to get the * to the "right" subscript
position (ie. somewhere near the baseline of the n)? thanks!

best regards,
andrew.

Andrew B. Collier

Physicist
Waves and Space Plasmas Group
Hermanus Magnetic Observatory

Honorary Senior Lecturer                             tel: +27 31 2601157
Space Physics Research Institute                     fax: +27 31 2607795
University of KwaZulu-Natal, Durban, South Africa    gsm: +27 83 3813655