Analyses of the short-period Cepheid SU Cassiopeiae

Baade-Wesselink analyses of this important Galactic classical Cepheid provi de new values for the radius, luminosity, distance, and mass and show SU Ca s likely to be pulsating in the first overtone. Application of a modified B aade-Wesselink technique and the maximum likelihood method, which we have p reviously applied to delta Scuti-type variables, yield values of [R] = 33.0 +/- 1.1 R., L = 1536 +/- 291 L., [M-V] = -3.28(+0.23)(-0.19), r = 486 +/- 52 pc, mass (from the Baade-Wesselink radius), M = 6.5 +/- 0.6 M. (assuming first-overtone pulsation), and evolutionary mass, M-ev = 5.5 +/- 0.3 M.. T he results are consistent with the Hipparcos satellite parallax, 2.31 +/- 0 .58 mas (433(-87)(+145) pc), providing further support for overtone pulsati on of SU Gas. In the course of the analyses, a modification to the maximum likelihood method, devised by one of us (W. J. F. W.), is presented as an a lternative to the modifications of Laney & Stobie and Coulson, Caldwell, & Gieren.