Circumbinary planets in coplanar triple-star systems: I. Minimum eccentricity variation region

@misc{gianuzzi2026circumbinary,
  title = {{Circumbinary planets in coplanar triple-star systems: I. Minimum eccentricity variation region}},
  author = {Emmanuel Gianuzzi and Mario Sucerquia and Nicolás Cuello and Cristian Giuppone},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.04450},
  eprint = {2609.04450},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.04450},
  note = {CC BY-NC-SA 4.0},
}

TY  - UNPB
TI  - Circumbinary planets in coplanar triple-star systems: I. Minimum eccentricity variation region
AU  - Emmanuel Gianuzzi
AU  - Mario Sucerquia
AU  - Nicolás Cuello
AU  - Cristian Giuppone
PY  - 2026
DA  - 2026/09/03
PB  - arXiv
DO  - 10.48550/arxiv.2609.04450
UR  - https://arxiv.org/abs/2609.04450
AB  - We aim to determine the conditions under which Lidov-Kozai oscillations can arise for circumbinary planets in hierarchical triple-star systems, and to identify the orbital regions where competing secular perturbations minimize eccentricity excitation. We analyzed the statistical properties of hierarchical triples from the Multiple Star Catalog to construct representative synthetic configurations. We then performed N-body simulations of circumbinary planets embedded in these systems, systematically exploring their orbital evolution and long-term stability across a range of semimajor axes and inclinations. For representative compact hierarchical triple-star systems with masses m_0 ∼ m_1 ≈ 0.75 M_⊙ and m_2 ≈ 0.6 M_⊙ and eccentricities e_1 ∼ 0.1 and e_2 ∼ 0.4, dynamically significant stable circumbinary regions exist only in sufficiently hierarchical configurations, with period ratios P_2 /P_1 ≳ 10^2. In this regime, the secular competition between the tertiary perturbations and the apsidal precession induced by the compact inner binary determines both the onset of Lidov-Kozai oscillations beyond a critical distance (a_LK) and the location of a region where eccentricity variations are minimized, i.e., the minimum eccentricity variation region (MER). We derived analytical estimates for these dynamical features, showing that the MER is well described by the analytical quantity a_short on short and intermediate timescales, while on secular timescales it converges toward the equilibrium prediction a_ME. These analytical estimates agree well with N-body simulations. Application to the observed triple system WDS 08403+1921 confirms that a_LK and a_ME accurately identify the main dynamical features of the stability map.
ER  -