The Sun as a planet-host star: Proxies from SDO images for HARPS radial-velocity variations

Abstract

The Sun is the only star whose surface can be directly resolved at high resolution, and therefore constitutes an excellent test case to explore the physical origin of stellar radial-velocity (RV) variability. We present HARPS observations of sunlight scattered off the bright asteroid 4/Vesta, from which we deduced the Sun's activity-driven RV variations. In parallel, the HMI instrument onboard the Solar Dynamics Observatory provided us with simultaneous high spatial resolution magnetograms, Dopplergrams, and continuum images of the Sun in the Fe I 6173A line. We determine the RV modulation arising from the suppression of granular blueshift in magnetised regions and the flux imbalance induced by dark spots and bright faculae. The rms velocity amplitudes of these contributions are 2.40 m/s and 0.41 m/s, respectively, which confirms that the inhibition of convection is the dominant source of activity-induced RV variations at play, in accordance with previous studies. We find the Doppler imbalances of spot and plage regions to be only weakly anticorrelated. Lightcurves can thus only give incomplete predictions of convective blueshift suppression. We must instead seek proxies that track the plage coverage on the visible stellar hemisphere directly. The chromospheric flux index R'_HK derived from the HARPS spectra performs poorly in this respect, possibly because of the differences in limb brightening/darkening in the chromosphere and photosphere. We also find that the activity-driven RV variations of the Sun are strongly correlated with its full-disc magnetic flux density, which may become a useful proxy for activity-related RV noise.

14 pages, 11 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society (2016 January 20) Supplementary Files available at: http://dx.doi.org/10.17630/bb43e6a3-72e0-464c-9fdd-fbe5d3e56a09

References in corpus (10)

• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• A new list of thorium and argon spectral lines in the visible
• Stellar Activity Masquerading as Planets in the Habitable Zone of the M dwarf Gliese 581
• The HARPS search for southern extra-solar planets. X. A m sin i = 11 Mearth planet around the nearby spotted M dwarf GJ 674
• TW Hydrae: evidence of stellar spots instead of a Hot Jupiter
• Stellar activity of planetary host star HD 189733
• A fast hybrid algorithm for exoplanetary transit searches
• Search for exoplanets with the radial-velocity technique: quantitative diagnostics of stellar activity
• The HARPS search for southern extra-solar planets XXXV. The interesting case of HD41248: stellar activity, no planets?
• Long-term radial-velocity variations of the Sun as a star: The HARPS view

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