HD 83443c: A Highly Eccentric Giant Planet on a 22 yr Orbit
Kane, Stephen R.; Butler, R. P.; Wittenmyer, Robert A.; Horner, Jonathan; Fetherolf, Tara; Shporer, Avi; Holt, Timothy R.; Bowler, Brendan P.; Brandt, G. Mirek; Tinney, C. G.; Clark, Jake T.; Kielkopf, John; Okumura, Jack; Wright, Duncan J.; Zhang, Hui; Li, Zhexing; Carter, Brad; Plavchan, Peter P.; Addison, Brett C.; Liu, Huigen; Mengel, Matthew W.; Ballard, Sarah; Errico, Adriana
Australia, United States, China
Abstract
We report the discovery of a highly eccentric long-period Jovian planet orbiting the hot-Jupiter host HD 83443. By combining radial velocity data from four instruments (AAT/UCLES, Keck/HIRES, HARPS, Minerva-Australis) spanning more than two decades, we find evidence for a planet with m sin $i={1.35}_{-0.06}^{+0.07}$ M J, moving on an orbit with a = 8.0 ± 0.8 au and eccentricity e = 0.76 ± 0.05. We combine our radial velocity analysis with Gaia eDR3 /Hipparcos proper motion anomalies and derive a dynamical mass of ${1.5}_{-0.2}^{+0.5}{M}_{\mathrm{Jup}}$ . We perform a detailed dynamical simulation that reveals locations of stability within the system that may harbor additional planets, including stable regions within the habitable zone of the host star. HD 83443 is a rare example of a system hosting a hot Jupiter and an exterior planetary companion. The high eccentricity of HD 83443c suggests that a scattering event may have sent the hot Jupiter to its close orbit while leaving the outer planet on a wide and eccentric path.