TOSC: an algorithm for the tomography of spotted transit chords

Abstract

Photometric observations of planetary transits may show localized bumps, called transit anomalies, due to the possible crossing of photospheric starspots. The aim of this work is to analyze the transit anomalies and derive the temperature profile inside the transit belt along the transit direction. We develop the algorithm TOSC, a tomographic inverse-approach tool which, by means of simple algebra, reconstructs the flux distribution along the transit belt. We test TOSC against some simulated scenarios. We find that TOSC provides robust results for light curves with photometric accuracies better than 1~mmag, returning the spot-photosphere temperature contrast with an accuracy better than 100~K. TOSC is also robust against the presence of unocculted spots, provided that the apparent planetary radius given by the fit of the transit light curve is used in place of the true radius. The analysis of real data with TOSC returns results consistent with previous studies.

References in corpus (13)

• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• The solar magnetic field
• Hubble Space Telescope times-series photometry of the planetary transit of HD189733: no moon, no rings, starspots
• The Magnetic Field in the Solar Atmosphere
• ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere
• Estimating stellar rotation from starspot detection during planetary transits
• Stellar parameters of early M dwarfs from ratios of spectral features at optical wavelengths
• spotrod: a semi-analytic model for transits of spotted stars
• Stellar activity as noise in exoplanet detection II. Application to M dwarfs
• The GAPS Programme with HARPS-N at TNG. VII. Putting exoplanets in the stellar context: magnetic activity and asteroseismology of $\tau$ Bootis A
• A cool starspot or a second transiting planet in the TrES-1 system?
• Stellar rotation--planetary orbit period commensurability in the HAT-P-11 system
• Disentangling planetary and stellar activity features in the CoRoT-2 light curve

Cited by in corpus (2)

• The Transit Light Source Effect II: The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars
• Synergies between space telescopes in the photometric characterization of the atmospheres of Hot Jupiters