English

Significant mutual inclinations between the stellar spin and the orbits of both planets in the HAT-P-11 system

Earth and Planetary Astrophysics 2025-02-03 v5

Abstract

Planet-star obliquity and planet-planet ]mutual inclination encode a planetary system's dynamical history, but both of their values are hard to measure for misaligned systems with close-in companions. HAT-P-11 is a K4 star with two known planets: a close-in, misaligned super-Neptune with a \approx5-day orbit, and an outer super-Jupiter with a \approx10-year orbit. In this work we present a joint orbit fit of the HAT-P-11 system with astrometry and S-index corrected RV data. By combining our results with previous constraints on the orientation of the star and the inner planet, we find that all three angular momenta -- those of the star, planet b, and planet c -- are significantly misaligned. We confirm the status of planet c as a super-Jupiter, with 2.68±0.41MJup2.68\pm0.41\, \mathrm{M_{\rm Jup}} at a semimajor axis of 4.10±0.064.10\pm0.06\,AU, and planet b's mass of Mbsinib=0.074±0.004MJup\mathrm{M_b\sin{i_b}}=0.074\pm0.004\, \mathrm{M_{\rm Jup}}. We present the posterior probability distribution of obliquity between star A and planet c, and mutual inclination between planet b and planet c.

Keywords

Cite

@article{arxiv.2405.19510,
  title  = {Significant mutual inclinations between the stellar spin and the orbits of both planets in the HAT-P-11 system},
  author = {Qier An and Tiger Lu and G. Mirek Brandt and Timothy D Brandt and Gongjie Li},
  journal= {arXiv preprint arXiv:2405.19510},
  year   = {2025}
}

Comments

14 pages, 10 figures, submitted to AJ