[astro-ph.EP] The PLATO Stellar Variability Mitigation Working Group designed a radial-velocity (RV) data challenge to assess the precision and accuracy achievable on RV semi-amplitudes in the context of the future PLATO follow-up.
Using Sun-as-a-star observations obtained with HARPS-N, we generated three multi-planet systems with realistic sampling, an effective signal-to-noise ratio of S/N ~ 450, an exposure time of 15 minutes, and a total of approximately 1000 observations. The resulting data set is publicly available and can serve as a benchmark for the community to test and compare RV analysis methods.
Eight independent teams participated in the challenge, aiming to recover the semi-amplitudes of both transiting and non-transiting planets. A meta-analysis of the submitted results shows that, with current data analysis methods, HARPS-N-like stability and the observing strategy studied in this paper, achieving a precision on semi-amplitudes better than 10% for habitable-zone signals around a solar-type star is challenging, and is typically limited to planets with masses of approximately 8-10 Earth masses.
This performance is expected to improve for K dwarfs, where planets down to approximately 2-5 Earth masses may be characterized at a similar level of precision. Finally, based on the results of this challenge and the occurrence of false positives, we derive an empirical detection threshold for RV surveys, which can be used to distinguish robust planetary detections from candidates.
M. Cretignier (1), N. C. Hara (2), S. Aigrain (1), S. Sulis (2), F. Bouchy (3), S. T. Hodgkin (4), J. Blanco-Pozo (5 and 6 and 7), A. Collier-Cameron (8), M. Damasso (9), E. C. Gonçalves (10), L. Malavolta (11 and 12), G. Mantovan (12), D. Nardiello (11 and 12), M. Perger (5 and 6), I. Ribas (5 and 6), Y. Zhao (13), X. Dumusque (3), A. Mortier (14), K. Al Moulla (10), S. C. C. Barros (10), A. Santerne (2 and 18), N. C. Santos (10 and 15), C. San Nicolas Martinez (10), C. Watson (16), T. Wilson (17), S. Udry (3), for the PLATO Stellar Variability Working Group ((1) University of Oxford, Oxford, (2) Aix Marseille Univ, France, (3) Astronomy Department of the University of Geneva, Switzerland, (4) Institute of Astronomy, Cambridge, (5) Institut de Ciencies de l’Espai ICE, Spain, (6) Institut d’Estudis Espacials de Catalunya IEEC, Spain, (7) Universitat de Barcelona, Spain, (8) SUPA School of Physics and Astronomy, University of St Andrews, (9) INAF Osservatorio Astrofisico di Torino, Italy, (10) Instituto de Astrofisica e Ciencias do Espaco, Portugal, (11) Dipartimento di Fisica e Astronomia Galileo Galilei, Italy, (12) Centro di Ateneo di Studi e Attivita Spaziali G. Colombo, Italy, (13) Department of Astronomy, University of Texas at Austin, USA, (14) University of Birmingham, UK, (15) Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Portugal, (16) Queen’s University Belfast, UK, (17) University of Warwick, UK, (18) Univ. Grenoble Alpes, France)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2610.36201 [astro-ph.EP] (or arXiv:2610.36201v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2610.36201
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Journal reference: MNRAS, 551, 2026
Related DOI:
https://doi.org/10.1093/mnras/stag1543
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Submission history
From: Michael Cretignier
[v1] Mon, 26 Oct 2026 19:38:39 UTC (2,985 KB)
https://arxiv.org/abs/2610.36201
Astrobiology,
