### Three-color photoelectric investigation of the eclipsing binary system RZ CassiopeiaeThree-color photoelectric investigation of the eclipsing binary system RZ Cassiopeiae

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 Author Chambliss, C. R. Sponsorship USDOE Source United States Department of Energy Office of Scientific and Technical Information Content type Text Language English
 Subject Keyword Physics (Astrophysics & Cosmology)-Stars ♦ Physics Research-Astrophysics & Cosmology-Stars ♦ BINARY STARS- ECLIPSE ♦ COLOR ♦ GIANT STARS ♦ MAIN SEQUENCE STARS ♦ ORBITS ♦ VARIATIONS ♦ VISIBLE RADIATION Abstract The semidetached eclipsing binary system RZ Cas was observed at Kutztown State College Observatory and at Kitt Peak National Observatory on 25 nights from January 1973 to January 1975. Approximately 600 observations each were obtained in yellow, blue, and ultraviolet. RZ Cas has long been known to have a variable period, and a new ephemeris based on the author's observations is given. RZ Cas consists of an A2V primary component paired with a subgiant component of spectral type about G5 IV. Solutions for its orbital elements were carried out using three different procedures; the Russell-Merrill method, the Kopal-Jurkevich iterative method, and the Wood triaxial ellipsoid model. For the first two procedures, rectified observations were used. The orbital elements obtained with these methods are in excellent agreement with each other but the temperature of the subgiant component derived from an analysis of the yellow light curve is about 500$sup 0$K lower than that obtained from the ultraviolet light curve. The Wood model produces orbital elements which differ significantly from those of the spherical model in some cases. A higher temperature is indicated for the subgiant component, but as before, a difference of about 500$sup 0$K is indicated between the yellow and ultraviolet light curves with the temperature derived from the blue light curve falling between them. Using the available spectroscopic data for RZ Cas, the masses of the components are estimated as 1.75 M/sub solar mass/ and 0.61 M/sub solar mass/ and their respective radii as 1.45 R/sub solar mass/ and 1.83 R/sub solar mass/. Both the mass and radius of the A2 V component are less than one would expect for a star of this type. RZ Cas is compared with the eclipsing binary V505 Sgr, a system whose primary is also an A 2V star, but of more normal size and mass. The visual absolute magnitude of RZ Cas is estimated as +2.0 and its distances as 70 parsecs. (auth) Educational Use Research Learning Resource Type Article Publisher Date 1976-02-01 Publisher Place United States Journal Publ. Astron. Soc. Pac. Volume Number 88 Issue Number 521 Organization Kutztown State Coll., PA