Simulations of starspot anomalies within TESS exoplanetary transit light curves -- I. The detection limits of starspot anomalies in TESS light curves

Abstract

20573 simulations of planetary transits around spotted stars were conducted using the transit-starspot model, \texttt{PRISM}. In total 3888 different scenarios were considered using three different host star spectral types, M4V, M1V and K5V. The mean amplitude of the starspot anomaly was measured and compared to the photometric precision of the light curve, to determine if the starspot anomaly's characteristic "blip" was noticeable in the light curve. The simulations show that, starspot anomalies will be observable in TESS 2\,min cadence data. The smallest starspot detectable in TESS transit light curves has a radius of $\approx 1900$\,km. The starspot detection limits for the three host stars are: $4900\pm 1700$\,km (M4V), $13800\pm 6000$\,km (M1V) and $15900\pm 6800$\,km (K5V). The smallest change in flux of the starspot ($\Delta F_{\mathrm{spot}}=0.00015\pm 0.00001$) can be detected when the ratio between the planetary and stellar radii, $k=0.082\pm 0.004$. The results confirm known dependencies between the amplitude of the starspot anomaly and the photometric parameters of the light curve. The results allowed the characterisation of the relationship between the change in flux of the starspot anomaly and the change in flux of the planetary transit for TESS transit light curves.

24 Pages, 12 Figures. Accepted for publication in A&A, section 10. Planets and planetary systems

References in corpus (13)

• The Transiting Exoplanet Survey Satellite
• The Dartmouth Stellar Evolution Database
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• Physics Of Eclipsing Binaries. II. Towards the Increased Model Fidelity
• Alignment of the stellar spin with the orbits of a three-planet system
• HATS-6b: A Warm Saturn Transiting an Early M Dwarf Star, and a Set of Empirical Relations for Characterizing K and M Dwarf Planet Hosts
• spotrod: a semi-analytic model for transits of spotted stars
• TESS delivers its first Earth-sized planet and a warm sub-Neptune
• A cool starspot or a second transiting planet in the TrES-1 system?
• Physical properties, starspot activity, orbital obliquity, and transmission spectrum of the Qatar-2 planetary system from multi-colour photometry
• Improvements on analytic modelling of stellar spots
• Activity and rotation of Kepler-17
• Possible detection of a bimodal cloud distribution in the atmosphere of HAT-P-32\,A\,b from multi-band photometry

Cited by in corpus (4)

• Can Sub-photospheric Magnetic Reconnection Change the Elemental Composition in the Solar Corona?
• The ultra-hot-Jupiter KELT-16 b: Dynamical Evolution and Atmospheric Properties
• Simulations of starspot anomalies within TESS exoplanetary transit light curves -- II
• Homogeneous search for spot transits in Kepler and TESS photometry of K $-$ M-type main-sequence stars