English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Stellar radial velocities play a fundamental role in the discovery ofextrasolar planets and the measurement of their physical parameters as well asin the study of stellar physical properties. We investigate the impact of thesolar activity on the radial velocity of the Sun using the HARPS spectrographto obtain measurements that can be directly compared with those acquired in theextrasolar planet search programs. We use the Moon, the Galilean satellites,and several asteroids as reflectors to measure the radial velocity of the Sunas a star and correlate it with disc-integrated chromospheric and magneticindexes of solar activity that are similar to stellar activity indexes. Wediscuss in detail the systematic effects that affect our measurements and themethods to account for them. We find that the radial velocity of the Sun as astar is positively correlated with the level of its chromospheric activity atabout 95 percent significance level. The amplitude of the long-term variationmeasured in the 2006-2014 period is 4.98 \pm 1.44 m/s, in good agreement withmodel predictions. The standard deviation of the residuals obtained bysubtracting a linear best fit is 2.82 m/s and is due to the rotation of thereflecting bodies and the intrinsic variability of the Sun on timescalesshorter than the activity cycle. A correlation with a lower significance isdetected between the radial velocity and the mean absolute value of theline-of-sight photospheric magnetic field flux density. Our results confirmsimilar correlations found in other late-type main-sequence stars and providesupport to the predictions of radial velocity variations induced by stellaractivity based on current models.

Long-term radial-velocity variations of the Sun as a star: The HARPS view