Abstract
AbstractDark spots on the surface of active stars produce changes in the shapes of the spectral lines that mimic spurious Doppler shifts, compromising the detection of small planets by means of the radial velocity (RV) technique. Modeling the spot‐driven RV variability (known as “jitter”) and how it affects the RV data sets is therefore crucial to design efficient activity‐filtering techniques and inform observing strategies. Here, we characterize starspots and simulate the RV curves induced by them to determine typical jitter amplitudes for a representative sample of 15 known host stars spanning between F and M spectral types. We collect information on the activity index from the literature for 205 stars and, due to a lack of data in the temperature range 4,000–4,500 K, we measure it for 10 stars using archival data. Additional stellar parameters required for the simulations are collected from the literature or constrained by observational data in order to derive realistic estimates. Our results can be used as reference to determine typical peak‐to‐peak spot‐induced RV jitter in the visible domain that can be expected when targeting host stars with different properties.
Highlights
The radial velocity (RV) technique is the second most prolific exoplanet hunting method, counting 21% of the total confirmed discoveries1
We find known host stars via exoplanet.eu (Schneider, Dedieu, Le Sidaner, Savalle, & Zolotukhin, 2011) and exoplanet.org (Han et al, 2014) and we look for magnetic activity information in the literature
The purpose of this plot is twofold: it allows a reasonable estimate of the RV jitter amplitude based on specific stellar parameters, informing observing strategies, and displays empirical relations between
Summary
The radial velocity (RV) technique is the second most prolific exoplanet hunting method, counting 21% of the total confirmed discoveries. Desort, Lagrange, Galland, Udry, & Mayor (2007) studied the case of a single spot on the surface of different F–K stars and with different active latitudes, inclinations and sin ; Lagrange, Desort, & Meunier (2010) investigated planet detection limits for G type stars using Sun-like spot coverage; Santos, Cunha, Avelino, & Campante (2015) used an empirical model to reconstruct a synthetic solar sunspot cycle; Andersen & Korhonen (2015) explored the M type regime and various activity levels, and Dumusque (2016) included instrumental, stellar and planetary signals in simulated RV data sets for G–K stars to analyze different recovery techniques.
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