Transit light curve and inner structure of close-in planets

Abstract

Planets orbiting very close to their host stars have been found, some of them on the verge of tidal disruption. The ellipsoidal shape of these planets can significantly differ from a sphere, which modifies the transit light curves. Here we present an easy method for taking the effect of the tidal bulge into account in the transit photometric observations. We show that the differences in the light curve are greater than previously thought. When detectable, these differences provide us an estimation of the fluid Love number, which is invaluable information on the internal structure of close-in planets. We also derive a simple analytical expression to correct the bulk density of these bodies, that can be 20% smaller than current estimates obtained assuming a spherical radius.

6 pages, 3 figures

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Cited by in corpus (14)

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• Retrieval of the fluid Love number $k_2$ in exoplanetary transit curves
• Detectability of shape deformation in short-period exoplanets
• Limb darkening measurements from TESS and Kepler light curves of transiting exoplanets
• Is the activity level of HD 80606 influenced by its eccentric planet?
• Tidal Response and Shape of Hot Jupiters
• HST/STIS capability for Love number measurement of WASP-121b
• Constraining the oblateness of transiting planets with photometry and spectroscopy
• Two neighbours of the ultra-short-period Earth-sized planet K2-157 b in the warm Neptunian savanna
• Relationship between the moment of inertia and the $k_2$ Love number of fluid extra-solar planets
• Tidal Distortions as a Bottleneck on Constraining Exoplanet Compositions
• Exploring Exoplanet Dynamics with JWST: Tides, Rotation, Rings, and Moons
• Yuti: A General-purpose Transit Simulator for Arbitrary Shaped Objects Orbiting Stars