A vigorous activity cycle mimicking a planetary system in HD200466

Abstract

Stellar activity can be a source of radial velocity (RV) noise and can reproduce periodic RV variations similar to those produced by an exoplanet. We present the vigorous activity cycle in the primary of the visual binary HD200466, a system made of two almost identical solar-type stars with an apparent separation of 4.6 arcsec at a distance of 44+/-2 pc. High precision RV over more than a decade, adaptive optics (AO) images, and abundances have been obtained for both components. A linear trend in the RV is found for the secondary. We assumed that it is due to the binary orbit and once coupled with the astrometric data, it strongly constrains the orbital solution of the binary at high eccentricities (e~0.85) and quite small periastron of ~21 AU. If this orbital motion is subtracted from the primary radial velocity curve, a highly significant (false alarm probability <0.1%) period of about 1300 d is obtained, suggesting in a first analysis the presence of a giant planet, but it turned out to be due to the stellar activity cycle. Since our spectra do not include the Ca~II resonance lines, we measured a chromospheric activity indicator based on the Halpha line to study the correlation between activity cycles and long-term activity variations. While the bisector analysis of the line profile does not show a clear indication of activity, the correlation between the Halpha line indicator and the RV measurements identify the presence of a strong activity cycle.

Accepted on Astronomy and Astrophysics Main Journal 2014, 16 pages, 18 figures

References in corpus (37)

• Validation of the new Hipparcos reduction
• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• No planet for HD 166435
• Radial Velocities for 889 Late-type Stars
• Chromospheric CaII Emission in Nearby F, G, K, and M stars
• Chromospheric Activity and Jitter Measurements for 2630 Stars on the California Planet Search
• Basic physical parameters of a selected sample of evolved stars
• Late-type stars members of young stellar kinematic groups - I. Single stars
• Radial Velocity Jitter in Stars from the California and Carnegie Planet Search at Keck Observatory
• Using the Sun to estimate Earth-like planets detection capabilities II. Impact of plages
• TW Hydrae: evidence of stellar spots instead of a Hot Jupiter
• Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program I. Comparison of activity indices
• Search for exoplanets with the radial-velocity technique: quantitative diagnostics of stellar activity
• Enhanced lithium depletion in Sun-like stars with orbiting planets
• Fluxes in Hαand Ca II H and K for a sample of Southern stars
• Multiple and changing cycles of active stars II. Results
• Lithium depletion and the rotational history of exoplanet host stars
• Testing blend scenarios for extrasolar transiting planet candidates. I. -- OGLE-TR-33: a false positive
• The HARPS search for southern extra-solar planets. XXX. Planetary systems around stars with solar-like magnetic cycles and short-term activity variation
• Abundance differences between components of wide binaries
• Searching for Planets in the Hyades III: The Quest for Short-Period Planets
• Evidence against the young hot-Jupiter around BD +20 1790
• The Chemical Compositions of Stars with Planets: A Review
• A giant planet in the triple system HD132563
• Galactic orbits of stars with planets
• On the correlation between Ca and Halpha solar emission and consequences for stellar activity observations
• Deriving the radial-velocity variations induced by stellar activity from high-precision photometry - Test on HD189733 with simultaneous MOST/SOPHIE data
• Line bisectors and radial velocity jitter from SARG spectra
• Lithium abundances in exoplanet-host stars : modelling
• A vigorous activity cycle mimicking a planetary system in HD200466
• Higher depletion of lithium in planet host stars: no age and mass effect
• Evidence of a massive planet candidate orbiting the young active K5V star BD+20 1790
• Lithium Abundances in Wide Binaries with Solar-Type Twin Components
• On the Nature of the Radial Velocity Variability of Aldebaran: A Search for Spectral Line Bisector Variations

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