Unexpectedly Strong Effect of Supergranulation on the Detectability of Earth Twins Orbiting Sun-like Stars With Radial Velocities

Magnetic activity and surface flows at different scales pertub radial velocity measurements.

This affects the detectability of low-mass exoplanets. In these flows, the effect of supergranulation is not as well characterized as the other flows, and we wish to estimate its effect on the detection of Earth-like planets in the habitable zone of Sun-like stars. We produced time series of radial velocities due to oscillations, granulation, and supergranulation, and estimated the detection limit for a G2 star and a period of 300 days. We also studied in detail the behavior of the power when the signal of a 1 Mearth planet was superposed on the signal from the stellar flows.

We find that the detection rate does not reach 100% except for the supergranulation level we assume, which is still optimistic, and for an excellent sampling. We conclude that with current knowledge, it is a very challenging task to find Earth twins around Sun-like stars with our current capabilities.

N. Meunier, A.-M. Lagrange
(Submitted on 19 Apr 2019)
Comments: Accepted in A&A Letters
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:1904.09089 [astro-ph.EP] (or arXiv:1904.09089v1 [astro-ph.EP] for this version)
Submission history
From: Nadege Meunier
[v1] Fri, 19 Apr 2019 06:25:45 UTC (71 KB)
https://arxiv.org/abs/1904.09089
Astrobiology