I am part of an international team of scientists who used JWST to observe one transit of L 98-59 d, a planet slightly larger and heavier than Earth, across the disc of its host star. We then obtained the transmission spectrum of the atmosphere of the exoplanet from these observations. This spectrum hinted at the possible presence of an atmosphere filled with sulphur dioxide and hydrogen sulphide. This discovery was surprising, as it stands out in stark contrast to the atmospheres of rocky planets in our own solar system, where water vapour and carbon dioxide are much more prevalent. Earth’s atmosphere, for example, is rich in nitrogen and oxygen, with trace amounts of water vapour. Meanwhile, Venus has a thick atmosphere dominated by carbon dioxide. Even Mars has a thin atmosphere dominated by carbon dioxide. Additional observations will be necessary to confirm the presence of these gases. To find out more about this, read the related paper or this article in the Conversation.
I am interested in understanding the atmospheres of potential Venus-like exoplanets, otherwise known and Exo-Venuses. I mostly work with NEMESISPY, a Python adaptation NEMESIS code for atmospheric retrieval of exoplanets.
I was a member the JWST ERS Transit Program. A part of the research conducted by this collaboration led to the first confirmation of atmospheric CO2 in the atmosphere of WASP 39 b using JWST.
I have explored the effect of centrifugal forces on the transmission spectra of an exoplanet atmosphere. The centrifugal acceleration due to a planet's rotation opposes the gravitational pull on a planet's atmosphere and increases its scale height. Conventional forward models used for low resolution space-based retrievals generally do not include this effect. I found that atmospheric retrievals produce significantly different results for close-in gas giant planets with low gravity when this assumption is removed, potentially underestimating gas abundances for a simulated planet analogous to WASP-19 b.
- Atmospheric Retrievals Suggest the Presence of a Secondary Atmosphere and Possible Sulfur Species on L98-59 d from JWST Nirspec G395H Transmission Spectroscopy, Banerjee, A.; Barstow, J.K.; Gressier, A.; Espinoza, N.; Sing, D.K. et al. ApJL, 975, L11, 2024
- Hints of a Sulfur-rich Atmosphere around the 1.6 R⊕ Super-Earth L98-59 d from JWST NIRspec G395H Transmission Spectroscopy, Gressier, A.; Espinoza, N.; Allen, N.H.; Sing, D.K.; Banerjee, A. et al. ApJL, 975, L10, 2024
- Effect of centrifugal force on transmission spectroscopy of exoplanet atmospheres, Banerjee, A.; Barstow, J.K.; Haswell, C.A.; Lewis, S.R., Monthly Notices of the Royal Astronomical Society: Letters, 523, L64, 2023
- Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM, Rustamkulov, Z., et al., Nature 614, 649–652 (2023)
- Identification of carbon dioxide in an exoplanet atmosphere, JWST Transiting Exoplanet Community Early Release Science Team, Nature 614, 649–652 (2023)
- Modelling the atmosphere of lava planet K2-141b: implications for low and high resolution spectroscopy, Nguyen, T.G.; Cowan, N.B.; Banerjee, A.; Moores, J.E., Monthly Notices of the Royal Astronomical Society, 499, 4605, 2020