A new third planet and the dynamical architecture of the HD33142 planetary system

Abstract

Based on recently-taken and archival HARPS, FEROS and HIRES radial velocities (RVs), we present evidence for a new planet orbiting the first ascent red giant star HD33142 (with an improved mass estimate of 1.52$\pm$0.03 M${}_{\odot }$), already known to host two planets. We confirm the Jovian mass planets HD33142 b and c with periods of $P_{\mathrm{b}}$ = 330.0${}_{-0.4}^{+0.4}$ d and $P_{\mathrm{c}}$ = 810.2${}_{-4.2}^{+3.8}$ d and minimum dynamical masses of $m_{\mathrm{b}}\sin i$ = 1.26${}_{-0.05}^{+0.05}$ M${}_{\mathrm{Jup}}$ and $m_{\mathrm{c}}\sin i$ = 0.89${}_{-0.05}^{+0.06}$ M${}_{\mathrm{Jup}}$. Furthermore, our periodogram analysis of the precise RVs shows strong evidence for a short-period Doppler signal in the residuals of a two-planet Keplerian fit, which we interpret as a third, Saturn-mass planet with $m_{\mathrm{d}}\sin i$ = 0.20${}_{-0.03}^{+0.02}$ M${}_{\mathrm{Jup}}$ on a close-in orbit with an orbital period of $P_{\mathrm{d}}$ =89.9${}_{-0.1}^{+0.1}$ d. We study the dynamical behavior of the three-planet system configurations with an N-body integration scheme, finding it long-term stable with the planets alternating between low and moderate eccentricities episodes. We also performed N-body simulations, including stellar evolution and second-order dynamical effects such as planet-stellar tides and stellar mass-loss on the way to the white dwarf phase. We find that planets HD33142 b, c and d are likely to be engulfed near the tip of the red giant branch phase due to tidal migration. These results make the HD33142 system an essential benchmark for the planet population statistics of the multiple-planet systems found around evolved stars.

Accepted for publication in AJ

References in corpus (20)

• The Transiting Exoplanet Survey Satellite
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Bayes in the sky: Bayesian inference and model selection in cosmology
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• CERES: A Set of Automated Routines for Echelle Spectra
• Stellar parameters and chemical abundances of 223 evolved stars with and without planets
• Accounting for velocity jitter in planet search surveys
• On the Semimajor Axis Distribution of Extrasolar Gas Giant Planets: Why Hot Jupiters Are Rare Around High-Mass Stars
• A nearby transiting rocky exoplanet that is suitable for atmospheric investigation
• Planet formation and migration near the silicate sublimation front in protoplanetary disks
• Bias and robustness of eccentricity estimates from radial velocity data
• The Pan-Pacific Planet Search. II. Confirmation of a two-planet system around HD 121056
• The fates of Solar system analogues with one additional distant planet
• A planetary system and a highly eccentric brown dwarf around the giant stars HIP67851 and HIP97233
• A pair of warm giant planets near the 2:1 mean motion resonance around the K-dwarf star TOI-2202
• N-body simulations of planet formation via pebble accretion II. How various giant planets form
• Disentangling 2:1 resonant radial velocity orbits from eccentric ones and a case study for HD 27894
• Two Jovian planets around the giant star HD202696. A growing population of packed massive planetary pairs around massive stars?
• Asteroseismic masses of four evolved planet-hosting stars using SONG and TESS: resolving the retired A-star mass controversy