We present Multiple Mirror Telescope ( MMT ) and Keck II telescope spectrophotometry and 3.5m Calar Alto telescope R , I photometry of the western component of the extremely low-metallicity blue compact galaxy SBS 0335–052 .
The components , separated by 22 kpc , appear to be members of a unique , physically connected system .
It is shown that SBS 0335–052W consists of at least three stellar clusters and has the same redshift as SBS 0335–052 .
The oxygen abundance in its two brightest knots is extremely low , 12 + log ( O/H ) = 7.22 \pm 0.03 and 7.13 \pm 0.08 , respectively .
These values are lower than in SBS 0335–052 and are nearly the same as those in I Zw 18 .
The ( R - I ) color profiles are very blue in both galaxies due to the combined effects of ionized gas and a young stellar population emission .
We argue that SBS 0335–052W is likely to be a nearby , young dwarf galaxy .