Z Draconis with two companions in a 2:1 mean-motion resonance

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Yuan J., ŞENAVCI H. V., Qian S.

RESEARCH IN ASTRONOMY AND ASTROPHYSICS, cilt.16, sa.5, 2016 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 16 Sayı: 5
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1088/1674-4527/16/5/081
  • Dergi Adı: RESEARCH IN ASTRONOMY AND ASTROPHYSICS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Anahtar Kelimeler: binaries: close, stars: individual (Z Draconis), methods: numerical, THERMAL RELAXATION OSCILLATION, PLANETARY SYSTEM HYPOTHESIS, BINARIES, DETECTABILITY
  • Ankara Üniversitesi Adresli: Evet

Özet

All available mid-eclipse times of the eclipsing binary Z Draconis are analyzed, and three sets of cyclic variations with periods of 20.1, 29.96 and 59.88 yr are found. The low-amplitude variations with a period of 20.1 yr may be attributed to the unavoidable slight imperfection in the double-Keplerian model, which gives periods of 29.96 and 59.88 yr. Interestingly, the Z Draconis system is close to a 2: 1 mean-motion resonance, or a 6: 3: 2 mean-motion resonance if the 20.1 yr period really exists. We also find that the best solutions tend to give the minimum eccentricities. Based on Kepler's third law, the outermost companion has a minimum mass of similar to 0.77 M-circle dot, whereas the middle companion is an M dwarf star with a mass of similar to 0.40 M-circle dot, suggesting that Z Draconis is a general N-body system.