Worlds Next Door. V. A Candidate Solar System Scale Super-Jupiter in the 61 Cygni Binary System

@misc{sanghi2026worlds,
  title = {{Worlds Next Door. V. A Candidate Solar System Scale Super-Jupiter in the 61 Cygni Binary System}},
  author = {Aniket Sanghi and Billy Quarles and Andrea S. J. Lin and Cheyanne Shariat and Pierre Kervella and James Mang and Dimitri Mawet and Mark R. Giovinazzi and Arvind F. Gupta and Charles Beichman and Bertrand Mennesson and Mathilde Mâlin and Jerry W. Xuan and Liton Majumdar and Jack J. Lissauer and Mark Wyatt and William O. Balmer and Eduardo Bendek and Kevin Wagner},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.32893},
  eprint = {2609.32893},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.32893},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Worlds Next Door. V. A Candidate Solar System Scale Super-Jupiter in the 61 Cygni Binary System
AU  - Aniket Sanghi
AU  - Billy Quarles
AU  - Andrea S. J. Lin
AU  - Cheyanne Shariat
AU  - Pierre Kervella
AU  - James Mang
AU  - Dimitri Mawet
AU  - Mark R. Giovinazzi
AU  - Arvind F. Gupta
AU  - Charles Beichman
AU  - Bertrand Mennesson
AU  - Mathilde Mâlin
AU  - Jerry W. Xuan
AU  - Liton Majumdar
AU  - Jack J. Lissauer
AU  - Mark Wyatt
AU  - William O. Balmer
AU  - Eduardo Bendek
AU  - Kevin Wagner
PY  - 2026
DA  - 2026/09/26
PB  - arXiv
DO  - 10.48550/arxiv.2609.32893
UR  - https://arxiv.org/abs/2609.32893
AB  - We present new constraints on a candidate third companion in the 61 Cygni binary system-one of the closest neighbors to our solar system (3.5 pc), the first stars to have a measured parallax, and two of the most favorable targets for habitable zone exo-Earth searches with future direct imaging missions. Kervella et al. (2022) first identified the candidate based on a 4.4σ tangential velocity anomaly in the system determined using Hipparcos and Gaia DR3 astrometry of the A and B components. We combine this astrometric evidence with constraints from Gaia DR3 RUWE, MMT/Clio Lp imaging, nearly four decades of radial velocity (RV) measurements (including ∼2 years of new NEID RVs presented here), and N-body dynamical stability calculations of both stars in a Monte Carlo framework to estimate the candidate companion's mass and semi-major axis. Our analysis reveals that all of the available data are compatible with an ≈(8 ± 3) M_Jup super-Jupiter in an ≈(8 ± 3) au orbit, with a broad range of allowed eccentricities and mutual inclinations. Using the Sonora Flame Skimmer evolutionary models, given the system's mature age of (6.0 ± 1.0) Gyr, we estimate a companion effective temperature of (282 ± 55) K and radius of (1.02 ± 0.02) R_Jup. Finally, we evaluate the stability of terrestrial planets in the habitable zone (HZ) of 61 Cygni AB in the presence of the giant planet candidate using N-body simulations. A companion semi-major axis ≲5 au, irrespective of the planet-planet mutual inclination, and between ≈5 au and 10 au, for misaligned orbits (40^o ≲ i_mut ≲ 140^o), severely disrupts the HZ. Our results highlight the need to confirm the planet candidate and characterize its orbit to inform future exo-Earth searches with missions such as SHERA, HWO, and LIFE.
ER  -