Simulations of starspot anomalies within TESS exoplanetary transit light curves -- II

Abstract

We determine the starspot detection rate in exoplanetary transit light curves for M and K dwarf stars observed by the Transiting Exoplanet Survey Satellite (TESS) using various starspot filling factors and starspot distributions. We used $3.6\times 10^9$ simulations of planetary transits around spotted stars using the transit-starspot model \prism. The simulations cover a range of starspot filling factors using one of three distributions: uniform, polar-biased, and mid-latitude. After construction of the stellar disc and starspots, we checked the transit cord for starspots and examined the change in flux of each starspot to determine whether or not a starspot anomaly would be detected. The results were then compared to predicted planetary detections for TESS. The results show that for the case of a uniform starspot distribution, $64\pm 9$ M dwarf and $23\pm 4$ K dwarf transit light curves observed by TESS will contain a starspot anomaly. This reduces to $37\pm 6$ M dwarf and $12\pm 2$ K dwarf light curves for a polar-biased distribution and $47\pm 7$ M dwarf and $21\pm 4$ K dwarf light curves for a mid-latitude distribution. Currently there are only 17 M dwarf and 10 K dwarf confirmed planetary systems from TESS, none of which are confirmed as showing starspot anomalies. All three starspot distributions can explain the current trend. However, with such a small sample, a firm conclusion can not be made at present. In the coming years when more TESS M and K dwarf exoplanetary systems have been detected and characterised, it will be possible to determine the dominant starspot distribution.

11 pages, 6 figures, and 7 tables. Accepted for publication in A&A

References in corpus (19)

• Physics Of Eclipsing Binaries. II. Towards the Increased Model Fidelity
• Alignment of the stellar spin with the orbits of a three-planet system
• Orbital misalignment of the Neptune-mass exoplanet GJ 436b with the spin of its cool star
• WASP-4b: a 12th-magnitude transiting hot-Jupiter in the Southern hemisphere
• 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
• The L 98-59 System: Three Transiting, Terrestrial-Sized Planets Orbiting a Nearby M-dwarf
• Detection of sodium in the atmosphere of WASP-69b
• WASP-80b: a gas giant transiting a cool dwarf
• WASP-80b has a dayside within the T-dwarf range
• Estimating stellar rotation from starspot detection during planetary transits
• spotrod: a semi-analytic model for transits of spotted stars
• TESS delivers its first Earth-sized planet and a warm sub-Neptune
• The GAPS Programme with HARPS-N at TNG. III: The retrograde orbit of HAT-P-18b
• 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
• The stellar obliquity, planet mass, and very low albedo of Qatar-2 from K2 Photometry
• Peculiar architectures for the WASP-53 and WASP-81 planet-hosting systems
• Physical properties of the WASP-44 planetary system from simultaneous multi-colour photometry
• Possible detection of a bimodal cloud distribution in the atmosphere of HAT-P-32\,A\,b from multi-band photometry

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