Viewing the PLATO LOPS2 Field Through the Lenses of TESS

TL;DR

This paper compares TESS and PLATO's observational capabilities in the LOPS2 field, highlighting TESS's extensive coverage and PLATO's superior sensitivity to smaller exoplanets, informing future exoplanet discovery strategies.

Contribution

It provides a detailed analysis of TESS and PLATO's observational overlap and sensitivities in the LOPS2 field, emphasizing the complementary nature of their exoplanet detection capabilities.

Findings

TESS will have monitored stars in LOPS2 for at least 330 days by 2025.

TESS is likely to have discovered most transiting giant planets up to 30 days.

PLATO will be more sensitive to smaller planets (1-4 R⊕), enabling new discoveries.

Abstract

PLATO will begin observing stars in its Southern Field (LOPS2) after its launch in late 2026. By this time, TESS will have observed the stars in LOPS2 for at least four years. We find that by 2025, on average each star in the PLATO field will have been monitored for 330 days by TESS, with a subset of stars in the TESS continuous viewing zone having over 1000 days of monitoring. There are currently 101 known transiting exoplanets in the LOPS2 field, with 36 of these residing in multiplanet systems. The LOPS2 field also contains more than 500 TESS planet candidate systems, 64 exoplanets discovered by radial velocity only, over 1000 bright (V$<$13) eclipsing binary systems, 7 transiting brown dwarf systems, and 2 bright white dwarfs (G$<$13). We calculate TESS and PLATO sensitivities to detecting transits for the bright FGK stars that make up the PLATO LOPS2 P1 sample. We find that TESS should have discovered almost all transiting giant planets out to approximately 30 d within the LOPS2 field, and out to approximately 100 d for the regions of the LOPS2 field within the TESS CVZ ($\sim20$ per cent of the LOPS2 field). However, we find that for smaller radius planets in the range 1-4 R$_\oplus$ PLATO will have significantly better sensitivity, and these are likely to make up the bulk of new PLATO discoveries.