Exoplanet Meteorology: Studying the Atmospheres Of Imaged Planets and Brown Dwarfs 

“Are we alone” – This is an eternal question that has haunted humanity for as long as we have been sentient. Searching for habitable worlds is a quest that I have undertaken as an astronomer. The atmosphere of these worlds is one of the best tools we have in this search, since it acts as a window into the myriad properties of the planet.

Research interests

A word jumble indicating my research interests :).

Here are some of the projects I have worked on –

Project 1: Determining the Atmosphere of HR8799 with HST/WFC3


Keck observations of the four planets orbiting HR 8799. (Credit: NRC/HIA, C. Marois, and Keck Observatory)

I studied the exoplanet system HR8799 using the Hubble Space Telescope. The main goals of the program was to measure the flux from the planet in the 1.3 – 1.5 micron water band which is unobservable from the ground as well as the neighboring wavelengths. These measurements were used to provide crucial constraints on the emitted energy at shorter wavelengths, which in turn improved our ability to measure the effective temperatures, surface gravities, cloud composition and the atmospheric chemical equilibria of these planets. 


Project 2: The Brown dwarf Atmosphere Monitoring (BAM) Project


This artist’s concept shows a brown dwarf with bands of clouds, thought to resemble those seen at Neptune and the other outer planets. Credits: NASA/JPL-Caltech

Exoplanets are very faint when compared to their host stars. This intrinsic faintness works against us when trying to characterize the planet.  Luckily there is a class of objects known as “Brown Dwarfs” which closely mimic the atmospheric behavior of large gas-giant planets.

The BAM project was initiated to try and understand the atmospheric dynamics of brown dwarfs across their complete measured temperature range. The projects consisted of surveying nearby brown dwarfs for atmospheric variations, which as shown in the movie, can be caused by clouds rotating in and out of view on the surface of the brown dwarfs. The results of both projects have been published.

Project 3: Exploring the atmosphere of the young Jupiter: 51 Eridani b 

51 Eri b IFU image + spectrum

Discovery data for 51 Eridani b. Macintosh+15, Rajan+17

The Gemini Planet Imager (GPI) is one of the most sophisticated instruments ever built for the purpose of detecting and characterizing exoplanets. GPI will carry out a census designed to detect and characterize planets in the critical 5-50 AU region required to fully understand the architecture of planetary systems. The GPI team, of which I am a member, has been approved 900 hrs to survey ~600 young, and nearby stars.

51 Eri b, the spectrum and discovery images shown above, is the first planet discovered by the survey. This young (~25 Myr) planet is one of the first imaged planets that might have formed via core accretion, thought to be the predominant method for planet formation.