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Subhajit Sarkar

Dr Subhajit Sarkar

Astronomy Group
Astronomy Instrumentation Group
Cardiff Hub for Astrophysics Research and Technology

School of Physics and Astronomy

Queen's Buildings - North Building, Room N/2.20, 5 The Parade, Newport Road, Cardiff, CF24 3AA
Available for postgraduate supervision


I'm a university lecturer and astrophysicist working in the field of extra-solar planets. I am involved in the development of new missions and observatories to characterise the atmospheres of exoplanets, in particular the ESA Ariel mission, as well as Twinkle and the NASA EXCITE mission.  I also am involved in cycle 1 and cycle 2 JWST exoplanet observations in collaboration with IoA Cambridge. I am interested in understanding atmospheric and planetary processes in temperate regime sub-Neptunes and gas giants, and how these relate to fundamental questions of planet formation and the diversity of the exoplanet population.  I am also interested in astrobiology, particularly the potential for biospheres in temperate sub-Neptunes and gas giants, how we may be able to determine the frequency of life-bearing worlds (the fL factor in the Drake Equation) and how exoplanetary observations might be able to constrain theories of the origin of life.




















Research focus

  • Development of new exoplanet observatories and missions
    • Ariel: first large-scale spectroscopic survey of exoplanet atmospheres.
      • I developed original versions of ExoSim/ArielSim observation simulator and Ariel Data Reduction Pipeline (ADaRP).  I lead the Simulations Working Group and am involved in a number of other ground segment and science working groups.  I am involved in the development of the Ariel data pipeline. I am Co-I on the UKSA Cardiff Ariel grant.
    • EXCITE: first dedicated exoplanet phase-curve spectroscopy observatory and first balloon-borne exoplanet observatory
      •  NASA collaborator/co-investigator
    • Twinkle: innovative UK-led space telescope for exoplanet spectroscopy
      • Developed TwinkleSim simulator and contributed to performance estimations.  Now a member of the Twinkle Science Team helping to shape the mission goals and science.
  • Exoplanet atmospheric spectroscopy
    • Sub-Neptunes:
      • Co-I on JWST Cycle 1 GO program 2722:
        'Chemical Disequilibrium in a Temperate sub-Neptune'. Approx. 20 hours. We use NIRISS, NIRSpec and MIRI to obtain the transmission spectrum of the sub-Neptune K2-18 b from 0.6 to 12 microns.
      • Co-I on JWST Cycle 2 GO program 3557:
        'A JWST Search for Missing Methane'.  Approx. 70 hours.  We will use NIRISS, NIRSpec and MIRI to obtain transmission spectra for 4 sub-Neptune/Neptune-sized planets.
    • Temperate gas giants (with Luke Booth):
      • Developing modeling and observational approaches to characterise this poorly-understood exoplanet population.
      • Lead the Cool Gas Giant working group for Twinkle and shaping the target list to perform first ever spectroscopic survey of cool gas giants.
    • Hot Jupiters:
      • Developed JexoPipe pipeline for JWST and applied this to hot Jupiter spectra.
  • Astrobiology
    • DRAKE (Dedicated Research for Advancing Knowledge of Exobiology): a proposed space mission to find the frequency of life in the Galaxy using transit spectroscopy (see paper in MNRAS).
    • Biospheres in temperate sub-Neptunes and gas giants

Software developed

  • ExoSim, ExoSim_N, JexoSim (JWST simulator), TwinkleSim, ADaRP, JexoPipe


Current undergraduate teaching

  • PX4245 / PXT145 Exoplanets and the Search for Life: Module Organiser
  • PX2140 Stars and Planets: Deputy Module Organiser

Previous undergraduate teaching

  • PX1127 Planet Earth: Module Organiser
  • PX2140 Stars and Planets: guest lecturer
  • PX1127 Planet Earth: Deputy Module Organiser
  • PX2134 Structured Programming: Lab supervisor
  • PX1125 Mathematical Practice for Physical Sciences: Marker
  • PX1222 Mathematical Methods for Physicists 2: Marker


  • I supervise PhD, MPhys, MSc and BSc research projects (see supervision page)



  • PhD, Astrophysics, Cardiff University
  • MSc (Distinction), Space Science, University College London
  • Diploma in Physics (Distinction), Open University
  • MA, Natural Sciences, Cambridge University
  • MB, BChir, Medicine, Cambridge University
  • Grad. Cert. Applied Sciences, Space Studies, University of South Australia
  • Space Studies Program, International Space University

Professional memberships

  • Fellow of the Royal Astronomical Society
  • Fellow of the Higher Education Academy

Academic positions

  • 2022- Present: Lecturer, School of Physics and Astronomy, Cardiff University
  • 2017-2021: Post-doctoral Research Associate, Cardiff University
  • 2013-2017: Post-graduate Research Student, Cardiff University
  • 2003-2005: Visiting Researcher, Space Medicine & Health Care Systems Office, NASA Johnson Space Center, Houston.
  • 2003-2005: Honorary Lecturer in Space Life Sciences, Dept. of Space & Climate Physics, University College London

Outreach and Media

  • BBC Radio Wales Science Cafe interview about the ARIEL space mission (April 2018).
  • Pythagorean Astronomy podcast interview about TESS, ARIEL and other exoplanet missions (April 2018).
  • Exoplanet talks for Cardiff AS Level Summer Programmes 2018/19.
  • Stargazing talk and telescope observing with Scouts (Spring 2019).
  • Online astronomy talk with Scouts (Winter 2020).
  • 'All About Space' magazine interview about Ariel mission ('Rise of the Exoplanet Hunter') (Jan 2021).
  • Twinkle mission YouTube video ('The Founding Members') (Aug 2021).
  • Pythagorean Astronomy podcast interview about JWST observing programme (Dec 2021).
  • Cardiff School of Physics & Astronomy YouTube video about JWST (Dec 2021).
  • BBC News Wales interview about exoplanets and JWST (July 2022).
  • Nature News and Views article on JWST (Feb 2023).
  • NASA/ESA Press release on JWST K2-18 b observation (Sep 2023)
  • BBC News interview about K2-18 b (Sep 2023)
  • K2-18 b interviews including: Le Parisien, News9Live (India), Kosmo magazine (Italy) (Sep 2023).

Committees and reviewing

  • I am the post-graduate admissions tutor for the Astronomy Group. 
  • I currently serve on the following school committees: a) Equality, diversity and inclusion (EDI), b) Environment and sustainability.
  • I am on the CHART-GEI Schools Engagement Project management team and the Astronomy Instrumentation Group management team.
  • I have previously served on the Ethics committee and MSc approval panel.
  • I have refereed publications for journals including MNRAS, PASP and Nature.


Current supervision

  • I am primary PhD supervisor for Luke Booth who is researching exoplanet atmospheres.
  • I am currently on the supervisory team as mentor for two PhD students.
  • I currently supervise the undergraduate projects "Missions to the planets" and "Exoplanet transmission spectroscopy"

Current supervision

Luke Booth

Luke Booth

PhD Student/Research Assistant

Past projects

  • Previous undergraduate and MSc projects include:  "Habitable exomoons", "Transmission spectroscopy of water", "Designing a telescope to observe Earth-like planet atmosphere", "Simulations for the Twinkle space mission", "Impact of star spots on exoplanet transmission spectroscopy"