Research

I work on characterising the atmospheres of exoplanets using high-resolution spectroscopy and primarily make use of the European Southern Observatory's (ESO) Very Large Telescope (VLT), in particular the recently upgraded CRIRES+ spectrograph, to observe phase curves of hot Jupiters (gas-giant planets that orbit closer than Mercury orbits our Sun) in the near-infrared. The NIR spectra of these gas giants are thought to be dominated by molecular features which control the escape of thermal radiation and are thus crucial for understanding the planet's climate.

(If you'd like to learn a bit about the different terminologies used to describe my research, take a look at the Terminologies tab - work in progress.)

Publications

  • All publications

  • First-author publications

    • Our recent work, which has been accepted for publication in MNRAS is outlined below.

    The day-side atmosphere of MASCARA-1b

    High-resolution emission spectrocopy retrievals of MASCARA-1b with CRIRES+

    (Ramkumar et al. 2023)

    My recent work focused on High-resolution emission spectroscopy observations of an ultra-hot Jupiter, MASCARA-1b, with the recently upgraded CRIRES+ spectrograph installed on UT3 of the VLT. MASCARA-1b is the first exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA) in 2017 (Talens et al. 2017) that targeted early-type stars, which are particularly challenging to follow up at fainter magnitudes. It orbits a bright, young and fast-rotating A8 star, MASCARA-1 (HD 201585), every 2.14 days and is pretty hot with an equilibrium temperature, Teq ≈ 2600 K.

    We observed the target in the K-band just before the secondary eclipse between ϕ ~ 0.32-0.42 (where ϕ = 0 corresponds to the central transit and ϕ = 0.5 corresponds to secondary eclipse) using the upgraded CRIRES+ spectrograph. These observations targeted the thermal emission spectrum of the planet day-side. Owing to the high S/N (signal-to-noise), we were able to detect strong emission signatures of CO (>15σ), H2O (>10σ) and Fe (≈8σ) in the day-side atmosphere of MASCARA-1b. Using the likelihood framework introduced in Gibson et al. 2020, we retrieved the abundances of the detected species and constrained the planetary orbital velocities, T-P profiles, and the carbon-to-oxygen ratio (C/O).

    A hypothetical visualisation of MASCARA-1b; Credits: NASA Eyes on Exoplanets.
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