HD 46375: seismic and spectropolarimetric analysis of a young Sun hosting a Saturn-like planet

Abstract

HD 46375 is known to host a Saturn-like exoplanet orbiting at 0.04 AU from its host star. Stellar light reflected by the planet was tentatively identified in the 34-day CoRoT run acquired in October-November 2008. We constrain the properties of the magnetic field of HD 46375 based on spectropolarimetric observations with the NARVAL spectrograph at the Pic du Midi observatory. In addition, we use a high-resolution NARVAL flux spectrum to contrain the atmospheric parameters. With these constraints, we perform an asteroseismic analysis and modelling of HD 46375 using the frequencies extracted from the CoRoT light curve. We used Zeeman Doppler imaging to reconstruct the magnetic map of the stellar surface. In the spectroscopic analysis we fitted isolated lines using 1D LTE atmosphere models. This analysis was used to constrain the effective temperature, surface gravity, and chemical composition of the star. To extract information about the p-mode oscillations, we used a technique based on the envelope autocorrelation function (EACF). From the Zeeman Doppler imaging observations, we observe a magnetic field of ~5 gauss. From the spectral analysis, HD 46375 is inferred to be an unevolved K0 type star with high metallicity [Fe/H]=+0.39. Owing to the relative faintness of the star (m_hip=8.05), the signal-to-noise ratio is too low to identify individual modes. However, we measure the p-mode excess power and large separation Delta nu_0=153.0 +/- 0.7 muHz. We are able do constrain the fundamental parameters of the star thanks to spectrometric and seismic analyses. We conclude that HD 46375 is similar to a young version of Alpha-CenB. This work is of special interest because of its combination of exoplanetary science and asteroseismology, which are the subjects of the current Kepler mission and the proposed PLATO mission.

arXiv commentAccepted in Astronomy & Astrophysics. 8 pages, 9 figures

References in corpus (38)

• Validation of the new Hipparcos reduction
• Spectroscopic [Fe/H] for 98 extra-solar planet-host stars: Exploring the probability of planet formation
• Catalog of Nearby Exoplanets
• The CoRoT satellite in flight : description and performance
• Magnetic fields of non-degenerate stars
• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• Stellar Turbulent Convection: A Selfconsistent Model
• Solar-like oscillations in alpha Centauri B
• Revised Primordial Helium Abundance Based on New Atomic Data
• Accurate fundamental parameters for 23 bright solar-type stars
• On detecting the large separation in the autocorrelation of stellar oscillation times series
• HAT-P-7: A Retrograde or Polar Orbit, and a Third Body
• Misaligned spin-orbit in the XO-3 planetary system?
• Searching for Star-Planet interactions within the magnetosphere of HD 189733
• Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph
• Magnetic cycles of the planet-hosting star tauBootis
• Magnetic cycles of the planet-hosting star Tau Bootis: II. a second magnetic polarity reversal
• Constraining fundamental stellar parameters using seismology. Application to Alpha Centauri AB
• Asteroseismic Investigation of Known Planet Hosts in the Kepler Field
• Excitation of solar-like oscillations across the HR diagram
• Parent Stars of Extrasolar Planets VII: New Abundance Analyses of 30 Systems
• The Liege Oscillation Code
• Sub-Saturn Planet Candidates to HD 16141 and HD 46375
• The Helium abundance and Delta Y / Delta Z in Lower Main Sequence stars
• Spectropolarimetric observations of the transiting planetary system of the K dwarf HD 189733
• The magnetic field of the planet-hosting star $\tau$ Bootis
• A fresh look at the seismic spectrum of HD49933: analysis of 180 days of CoRoT photometry
• Short-lived spots in solar-like stars as observed by CoRoT
• A spectroscopic study of southern (candidate) gamma Doradus stars. II. Detailed abundance analysis and fundamental parameters
• Solar-like oscillations with low amplitude in the CoRoT target HD 181906
• Solar-like oscillations in the G8 V star tau Ceti
• Abundance analysis of targets for the COROT / MONS asteroseismology missions II. Abundance analysis of the COROT main targets
• The CoRoT target HD175726: an active star with weak solar-like oscillations
• The exoplanet-host star iota Horologii: an evaporated member of the primordial Hyades cluster
• CoRoT/ESTA-TASK 1 and TASK 3 comparison of the internal structure and seismic properties of representative stellar models: Comparisons between the ASTEC, CESAM, CLES, GARSTEC and STAROX codes
• HD 203608, a quiet asteroseismic target in the old galactic disk
• SYMPA, a dedicated instrument for Jovian Seismology. II. Real performance and first results
• Possible detection of phase changes from the non-transiting planet HD 46375b by CoRoT

Cited by in corpus (21)

• An ancient extrasolar system with five sub-Earth-size planets
• Observations of Cool-Star Magnetic Fields
• A uniform asteroseismic analysis of 22 solar-type stars observed by Kepler
• Mixed modes in red-giant stars observed with CoRoT
• Magnetic Wreaths and Cycles in Convective Dynamos
• Asymptotic and measured large frequency separations
• Accurate p-mode measurements of the G0V metal-rich CoRoT target HD 52265
• A small survey of the magnetic fields of planet-host stars
• Buoyant Magnetic Loops Generated by Global Convective Dynamo Action
• CoRoT: harvest of the exoplanet program
• Transit confirmation and improved stellar and planet parameters for the super-Earth HD 97658 b and its host star
• Limits on surface gravities of Kepler planet-candidate host stars from non-detection of solar-like oscillations
• The Most Massive Heartbeat: An In-depth Analysis of ι Orionis
• Convective boundary mixing in low- and intermediate-mass stars I. Core properties from pressure-mode asteroseismology
• $\epsilon$ Lupi: measuring the heartbeat of a doubly-magnetic massive binary with BRITE-Constellation
• CoRoT and Kepler results: Solar-like oscillators
• Seismic analysis of HD43587Aa, a solar-like oscillator in a multiple system
• Time-Series Analysis of Broadband Photometry of Neptune from K2
• Differential asteroseismic study of seismic twins observed by CoRoT; Comparison of HD 175272 with HD 181420
• Observational techniques to measure solar and stellar oscillations
• Pulsating stars harbouring planets