a type of star showing bright emission lines superimposed on its normal absorption spectrum, presumably caused by a gaseous shell around the star.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for shell star
astronomy a type of star, usually of spectral type B to F, surrounded by a gaseous shell
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012