THE STARBURST GALAXY PG-1136-1450 MISCLASSIFIED AS A CATACLYSMIC VARIABLE(581=MKN)

From direct CCD imaging, BVR(C)I(C) photometry, low- and high-resoluti on spectrophotometry it is shown that PG 1136+581 is not a cataclysmic variable as reported in the Palomar Green survey, but a small and fai nt starburst galaxy at z=0.00280 identical to Markarian 1450. The emis sion line spectrum well conforms to the expectations of Case B under l ow electron densities. The emission lines are very narrow (<FWHM> simi lar to 44 km sec(-1)) and the forbidden ones particularly strong, with [O III] 5007 Angstrom/H alpha = 2. The reddening amounts to E(B-V)=0. 07. The narrowness of the emission lines and absence of photometric va riability in excess of 0.1 mag over the period 1983-1991 tends to excl ude the presence of any AGN-like activity. In spite of some gaps in th e photometric patrolling, it is quite possible that no supernova has e xploded in PG 1136+581 during the period 1983-1991.