Evidence of a brown dwarf in the eclipsing dwarf nova Z Chamaeleonis
We presented three new CCD observations of light minima of Z Chamaeleonis. All 187 available times of light minimum including 37 photographic data are compiled, and a new orbital period analysis is made by means of the standard O - C technique. The O - C diagram of Z Chamaeleonis presents a cyclical...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2009 |
| País: | Argentina |
| Institución: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/82785 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/82785 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Astronómicas Binaries:eclipsing Cataclysmic variables Novae Stars:individual (Z Chamaeleonis) |
| Sumario: | We presented three new CCD observations of light minima of Z Chamaeleonis. All 187 available times of light minimum including 37 photographic data are compiled, and a new orbital period analysis is made by means of the standard O - C technique. The O - C diagram of Z Chamaeleonis presents a cyclical periodic change of 32.57 yr with a high significance level. We attempted to apply two plausible mechanisms (i.e., Applegate's mechanism and light travel-time effect) to explain the cyclical variations of orbital period shown in the O-C diagram. Although the previous works suggested that solar-type magnetic cycles in the red dwarf are the best explanation, the analysis of Applegate's mechanism in this paper presents a negative result. Accordingly, a light travel-time effect is proposed, and a brown dwarf as a tertiary component orbiting around dwarf nova Z Chamaeleonis is derived with a significance level of ≳81.6%, which may be a plausible explanation of the periodic variation in the systemic velocity of Z Chamaeleonis in superoutburst. |
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