noun, plural: astrospheres
The astrosphere is the part of the aster containing a definite set and pattern of microtubules. In certain references, the term astrosphere does not include the astral rays. In other references, it is used synonymously with the aster and centrosphere. However, the etymology of the word implies that the term pertains to the core of the aster.
Word origin: astro- from Greek ástron (a star) + -sphere from Latin sphaera (globe), from Greek sphaîra (ball)