Two Stars in Sagittarius With Changing Periods

Volume 1 number 2 (1972)

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Pamela R. Knight

Abstract

My work at The Maria Mitchell Observatory during the summer of 1972 was done on stars in VSF 193 in Sagittarius. In this paper I would like to discuss two stars which were found to have changing periods - one a long period Mira type and the other a short period RR Lyrae type. The first of these stars temporarily designtated as B15, (RA 18h 20m 52s, Dec. -28° 27:8, 1900, mag. range 12.6-14.5pg), was discovered at Nantucket during the summer of 1971 by Karen Kwitter. I re-estimated it on approximately 500 NA plates and about 200 MF and B plates by comparing its brightness on each plate to standard comparison stars. Next the magnitude estimates were plotted against Julian day on a scale of 100 days to the inch, and some pieces of light curves began to be visible.