Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars

Abstract

We present four new exoplanets: HIP 14810 b & c, HD 154345 b, and HD 187123 c. The two planets orbiting HIP 14810, from the N2K project, have masses of 3.9 and 0.76 M_jup. We have searched the radial velocity time series of 90 known exoplanet systems and found new residual trends due to additional, long period companions. Two stars known to host one exoplanet have sufficient curvature in the residuals to a one planet fit to constrain the minimum mass of the outer companion to be substellar: HD 68988 c with 8 M_jup < M sini < 20 M_jup and HD 187123 c with 3 M_jup < msini < 7 M_jup$, both with P > 8 y. We have also searched the velocity residuals of known exoplanet systems for prospective low-amplitude exoplanets and present some candidates. We discuss techniques for constraining the mass and period of exoplanets in such cases, and for quantifying the significance of weak RV signals. We also present two substellar companions with incomplete orbits and periods longer than 8 y: HD 24040 b and HD 154345 b with M sini < 20 M_jup and M sini < 10 M_jup, respectively.

Accepted to ApJ, v656(2), 20 Feb 2007. 15 figures, 6 tables v.2, v.3: minor typos from corrected

References in corpus (1)

• Long-Period Objects in the Extrasolar Planetary Systems 47 UMa and 14 Her

Cited by in corpus (5)

• Dynamical Outcomes of Planet-Planet Scattering
• Origins of Eccentric Extrasolar Planets: Testing the Planet-Planet Scattering Model
• HD147506b: A Super-Massive Planet in an Eccentric Orbit Transiting a Bright Star
• Optimal strategies of radial velocity observations in planet search surveys
• A Third Planet Orbiting HIP 14810