14 Her: a likely case of planet-planet scattering

• Published in: arXiv.org 2021-11
• Main Authors: Daniella C Bardalez Gagliuffi, Faherty, Jacqueline K, Li, Yiting, Brandt, Timothy D, Williams, Lauryn, Brandt, G Mirek, Gelino, Christopher R
• Format: Article
• Language: English
• Subjects: Acceleration; Coplanarity; Planetary orbits; Radial velocity; Scattering
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2111.06004

In this Letter, we measure the full orbital architecture of the two-planet system around the nearby K0 dwarf 14 Herculis. 14 Her (HD 145675, HIP 79248) is a middle-aged (\(4.6^{+3.8}_{-1.3}\) Gyr) K0 star with two eccentric giant planets identified in the literature from radial velocity (RV) variability and long-term trends. Using archival RV data from Keck/HIRES in concert with \textit{Gaia-Hipparcos} acceleration in the proper motion vector for the star, we have disentangled the mass and inclination of the b planet to \({9.1}_{-1.1}^{+1.0}\) \(M_\mathrm{Jup}\) and \({32.7}_{-3.2}^{+5.3}\) degrees. Despite only partial phase coverage for the c planet's orbit, we are able to constrain its mass and orbital parameters as well to \({6.9}_{-1.0}^{+1.7}\) \(M_\mathrm{Jup}\) and \({101}_{-33}^{+31}\) degrees. We find that coplanarity of the b and c orbits is strongly disfavored. Combined with the age of the system and the comparable masses of its planets, this suggests that planet-planet scattering may be responsible for the current configuration of the system.