Answer: reddwarf

AnswerCrossword Clue
REDDWARF

For "..." the student wrote "Bashful"...

REDDWARF

Faint, low-temperature star

REDDWARF

Proxima Centauri, for one

REDDWARF
Relatively low-temperature star
REDDWARF
Proxima Centauri, e.g.
REDDWARFBarnard's Star, for one
REDDWARFBashful?