We analyse observations , spanning 15 years , dedicated to the extreme emission-line object Hen 3-209 .
Our photometric data indicate that the luminosity of the star undergoes marked variations with a peak-to-peak amplitude of 0.65 mag .
These variations are recurrent , with a period of 16.093 \pm 0.005 d. The spectrum of Hen 3-209 is peculiar with many different lines ( H i , He i , Fe ii , … ) showing P Cygni profiles .
The line profiles are apparently changing in harmony with the photometry .
The spectrum also contains [ O iii ] lines that display a saddle profile topped by three peaks , with a maximum separation of about 600 km s ^ { -1 } .
Hen 3-209 is most likely an evolved luminous object suffering from mass ejection events and maybe belonging to a binary system .