Long-term luminosity variations and period changes in CG Cygni
Abstract
We report new photometry of CG Cyg from 1998-2002. We also analyze published photometry collected since 1965. An O-C analysis reveals evidence of a third body in the system having a 51 year orbital period. After removing the effects of the third body, we note a remaining 22.5 year cyclic variation in the O-C curve that is similar to the period of the luminosity variations. Modeling the spot activity for 28 V band light curves obtained between 1965 and 2002 confirms the presence of two active longitude belts (ALBs) at approximately 90° and 270°. Most of the spots occur at mid latitudes with a few at low latitudes. We note no spots at latitudes greater than 60°.
Tables 2, 3 and 5 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/420/595- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 2004
- DOI:
- 10.1051/0004-6361:20040115
- Bibcode:
- 2004A&A...420..595A
- Keywords:
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- stars: activity;
- stars: binaries: eclipsing;
- stars: individual: CG Cyg;
- stars: starspots