Precise Photometric Transit Follow-up Observations of Five Close-in Exoplanets: Update on Their Physical Properties

Abstract

We report the results of the high precision photometric follow-up observations of five transiting hot jupiters -WASP-33b, WASP-50b, WASP-12b, HATS-18b and HAT-P-36b. The observations are made from the 2m Himalayan Chandra Telescope at Indian Astronomical Observatory, Hanle and the 1.3m J. C. Bhattacharyya Telescope at Vainu Bappu Observatory, Kavalur. This exercise is a part of the capability testing of the two telescopes and their back-end instruments. Leveraging the large aperture of both the telescopes used, the images taken during several nights were used to produce the transit light curves with high photometric S/N (> 200) by performing differential photometry. In order to reduce the fluctuations in the transit light curves due to various sources such as stellar activity, varying sky transparency etc. we preprocessed them using wavelet denoising and applied Gaussian process correlated noise modeling technique while modeling the transit light curves. To demonstrate the efficiency of the wavelet denoising process we have also included the results without the denoising process. A state-of-the-art algorithm used for modeling the transit light curves provided the physical parameters of the planets with more precise values than reported earlier.

Pseudo-2D Modelling of Heat Redistribution Through H$_2$ Thermal Dissociation/Recombination: Consequences for Ultra-Hot Jupiters

“…WASP-12b has an unusually high day-side temperature, in places reaching ≥ 3000 K (Swain et al 2013), and an equilibrium temperature of ∼2500 K (Chakrabarty & Sengupta 2019). This atmosphere represents an interesting case between planetary and stellar conditions.…”

“…Sophisticated multi-dimensional atmospheric models exist for these planets, and high speed variable winds have been predicted through modelling (Guillot & Showman 2002;Mayne et al 2014) and inferred from observations (Snellen et al 2010). For UHJs, such as WASP-12b, the day-side equilibrium temperature can reach ≥ 2500 K (Chakrabarty & Sengupta 2019), with night-side temperatures ≥ 1000 K colder (Cowan et al 2012). This extreme temperature gradient between the two hemispheres drives global circulation in the form of particularly strong longitudinal winds, dominated by an equatorial jet, in some cases reaching speeds of over 5 km s −1 (Komacek et al 2017).…”

Pseudo-2D modelling of heat redistribution through H2 thermal dissociation/recombination: consequences for ultra-hot Jupiters

“…This method has also been used in the latest version of the Met Office Unified Model (UM), creating a field to implement variable heat capacity (Drummond et al 2018a). ature of ∼2500 K (Chakrabarty & Sengupta 2019). This atmosphere represents an interesting case between planetary and stellar conditions.…”

“…Sophisticated multi-dimensional atmospheric models exist for these planets, and high speed variable winds have been predicted through modelling (Guillot & Showman 2002;Mayne et al 2014) and inferred from observations (Snellen et al 2010). For UHJs, such as WASP-12b, the day-side equilibrium temperature can reach ≥ 2500 K (Chakrabarty & Sengupta 2019), with night-side temperatures ≥ 1000 K colder (Cowan et al 2012). This extreme temperature gradient between the two hemispheres drives alexander.roth@physics.ox.ac.uk global circulation in the form of particularly strong longitudinal winds, dominated by an equatorial jet, in some cases reaching speeds of over 5 km s −1 (Komacek et al 2017).…”

Generic Models for Disk-Resolved and Disk-Integrated Phase Dependent Linear Polarization of Light Reflected from Exoplanets

“…For the transiting planets i.e. planets with orbital inclination angle ∼ 90 • , these physical properties can be precisely estimated from transit photometric observations (e.g., Chakrabarty & Sengupta 2019;Addison et al 2019;Saha, Chakrabarty & Sengupta 2021). On the other hand, the course knowledge of the atmospheric chemical composition and cloud structure estimated from observation and modeling of transmission spectra (e.g., Wilson et al 2021;Sengupta, Chakrabarty & Tinetti 2020;Sing et al 2016) or emission spectra (e.g., Nikolov et al 2018;Evans et al 2017) of the transiting exoplanets helps us develop models for the polarized reflected light observable from those planets.…”