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

In photometry, the short-timescale stellar variability ("flicker"), such asthat caused by granulation and oscillations, can reach amplitudes comparable tothe transit depth of Earth-sized planets and is correlated over the typicaltransit timescales. It can introduce systematic errors on the inferredplanetary parameters when a small number of transits are observed. Theobjective of this paper is to characterize the statistical properties of thisnoise and quantify its impact on the inferred transit parameters. We used theextensive solar observations obtained with SoHO/VIRGO to characterize flickernoise. We simulated realistic transits across the solar disk using SDO/HMI dataand used these to obtain transit light curves, which we used to estimate theerrors made on the transit parameters. We make these light curves publiclyavailable. To extend the study to a wider parameter range, we derived theproperties of flicker noise using Kepler observations and studied theirdependence on stellar parameters. Finally, we predicted the limiting stellarapparent magnitude for which the properties of the flicker noise can beextracted using high-precision CHEOPS and PLATO observations. Stellargranulation is a stochastic colored noise, and is stationary with respect tothe stellar magnetic cycle. Both the flicker correlation timescales andamplitudes increase with the stellar mass and radius. If these correlations arenot taken into account when fitting for the parameters of transitingexoplanets, this can bias the inferred parameters. In particular, we finderrors of up to 10$\%$ on $R_p/R_s$ for an Earth-sized planet orbiting aSun-like star. For F and G stars, flicker will significantly affect theinferred parameters of transits observed with CHEOPS and PLATO. Dedicatedmodeling strategies need to be developed to accurately characterize both thestar and the transiting exoplanets.

astronomy and astrophysics

Mitigating flicker noise in high-precision photometry. I --  Characterization of the noise structure, impact on the inferred transit  parameters, and predictions for CHEOPS observations