MOCKA – A PLATO mock asteroseismic catalogue: Simulations for gravity-mode oscillators
Authors: Jannsen N. , Tkachenko A. , Royer P. , De Ridder J. , Seynaeve D. , Aerts C. , Aigrain S. , Plachy E. , Bodi A. , Uzundag M. , Bowman D. M. , Fritzewski D. J. , IJspeert L. W. , Li G. , Pedersen M. G. , Vanrespaille M. , Van Reeth T. 
Published: January 2025

Context. With the PLAnetary Transits and Oscillation of stars (PLATO) space mission set for launch in December 2026 by the European Space Agency (ESA), a new photometric legacy and a future of new scientific discoveries await the community. By exploring scientific topics outside of the core science program, the PLATO complementary science program (PLATO-CS) provides a unique opportunity to maximise the scientific yield of the mission.

Aims. In this work, we investigate PLATO’s potential for observing pulsating stars across the Hertzsprung–Russell diagram (HRD). This search is distinct from the core science program. Here, we present a PLATO mock asteroseismic catalogue (MOCKA) of intermediate to massive stars as a benchmark to highlight the asteroseismic yield of PLATO-CS in a quantitative way. MOCKA includes simulations of β Cephei, slowly pulsating B (SPB), δ Scuti, γ Doradus, RR Lyrae, Cepheid, hot sub-dwarf, and white dwarf stars. In particular, main sequence gravity (g) mode pulsators are of interest, as some of these stars form an important foundation for the scientific calibration of PLATO. Their pulsation modes primarily probe the radiative region near the convective core boundary, making them unique stellar laboratories for studying the deep internal structure of stars.

Methods. MOCKA is based on a magnitude-limited (G ≲ 17) Gaia catalogue. It is a product of realistic end-to-end PlatoSim simulations of stars for the first PLATO pointing field in the southern hemisphere, which will be observed for a minimum duration of two years. Comprising a state-of-the-art hare-and-hound detection exercise, the simulations of this project explore the impact of spacecraft systematics and stellar contamination on the on-board PLATO light curves.

Results. We demonstrate, for the first time, PLATO’s ability to detect and recover the oscillation modes for main sequence g-mode pulsators. We show that an abundant spectrum of frequencies is achievable across a wide range of magnitudes and co-pointing PLATO cameras. Within the magnitude-limited regimes simulated in this work (G ≲ 14 for γ Doradus stars and G ≲ 16 for SPB stars), the dominant g-mode frequency was recovered in more than 95% of cases. Furthermore, we find that an increased spacecraft noise budget impacts the recovery of g modes more than the stellar contamination by variable stars.

Conclusions. MOCKA helps improve our understanding of the limits of the PLATO mission, as well as to highlight the opportunities to push astrophysics beyond current stellar models. All the data products of this paper are made available to the community for further exploration. The key data products of MOCKA can be found include the magnitude-limited Gaia catalogue of the first PLATO pointing field, together with fully reduced light curves from multi-camera observations for each pulsation class.