Long-term starspot activity of short-period RS canum venaticorum stars. 5: CG Cygni

Abstract

view Abstract Citations (41) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Long-Term Starspot Activity of Short-Period RS Canum Venaticorum Stars. V. CG Cygni Zeilik, M. ; Gordon, S. ; Jaderlund, E. ; Ledlow, M. ; Summers, D. L. ; Heckert, P. A. ; Budding, E. ; Banks, T. S. Abstract We perform a parameter optimization of photometric light curves and distortion waves for the short-period RS CVn system CG Cyg. The distortion-wave curve fitting relies on a dark, circular spot model for the active regions on the photosphere of the primary star. Our information limit optimization process uses a phenomenological starspot model to find starspot parameters relevant to magnetic activity cycles: longitude, latitude, radius, and temperature (if simultaneous visual and red data are available). For 1989 observations, we find that the mean difference in temperature between the spotted regions and primary star's photosphere was 1100 +/- 170 K. From recent observations (1991) and archival data back to 1921, we find (1) the active regions fall into two active longitude belts (ALBs) generally at the quadrature longitudes; (2) usually one ALB exhibits large spots at any time; (3) the spotted regions tend to be large (radii approximately 20 deg) and fall near high latitudes (approximately greater than or equal to 45 deg); and (4) the magnetic activity within one ALB has a time scale approximately 1 yr. Rarely is activity visible in both ALBs at the same time. In 1991, we observed a rapid transition (approximately 1 month) between activity in both ALBs and activity in only one. Publication: The Astrophysical Journal Pub Date: January 1994 DOI: 10.1086/173647 Bibcode: 1994ApJ...421..303Z Keywords: Astronomical Models; Astronomical Photometry; Eclipsing Binary Stars; Light Curve; Optimization; Parameterization; Sunspots; Charge Coupled Devices; Statistical Analysis; Stellar Physics; Astrophysics; STARS: ACTIVITY; STARS: BINARIES: ECLIPSING; STARS: INDIVIDUAL CONSTELLATION NAME: CG CYGNI full text sources ADS | data products SIMBAD (2) Related Materials (4) Part 1: 1986BAAS...18..955Z Part 2: 1989ApJ...345..991Z Part 3: 1990ApJ...354..352Z Part 4: 1990ApJ...363..647Z