Published February 26, 2021 | Version v1
Poster Open

Observing planet-starspot crossings with the James Webb Space Telescope

  • 1. INAF - Catania Astrophysical Observatory
  • 2. Department of Astronomy and Carl Sagan Institute, Cornell University
  • 3. Space Telescope Science Institute
  • 4. Space Science Institute Center for Data Science, Space Science Institute Center for Exoplanet and Planetary Science
  • 5. University of Arizona
  • 6. Department of Physics and Astronomy, Johns Hopkins University
  • 7. INAF - Osservatorio Astronomico di Palermo
  • 8. INAF - Osservatorio Astronomico di Palermo, Dipartimento di Fisica e Chimica Emilio Segré, Università di Palermo


Transiting exoplanets orbiting active stars frequently occult starspots and faculae on the visible stellar disc. Such occultations can provide useful constraints to retrieve the temperature of active features and their effect on transmission spectra. We analyse the constraints that the James Webb Space Telescope will be able to place on the spectra of starspots, despite its lack of optical wavelength instruments on board. Focusing on K and M spectral types, we find that starspot temperatures can be determined to within a few hundred kelvins using NIRSpec/Prism and the proposed NIRCam/F150W2+F322W2’s broad wavelength capabilities.


GB acknowledges support from CHEOPS ASI-INAF agreement n. 2019-29-HH.0. GM and GC acknowledge the support of the ARIEL ASI-INAF agreement n.2018-22-HH.0. This research has made use of the SVO Filter Profile Service ( supported from the Spanish MINECO through grant AYA2017-84089.



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  • Batalha N. E., et al., 2017, Publications of the Astronomical Society of thePacific, 129, 064501
  • Schlawin E., et al., 2016, Publications of the Astronomical Society of thePacific, 129, 015001
  • Montalto M., Boué G., Oshagh M., Boisse I., Bruno G., Santos N. C., 2014,MNRAS, 444, 1721
  • Sarkar S., Madhusudhan N., Papageorgiou A., 2020, MNRAS, 491, 378; Sing D. K., et al., 2011, MNRAS, 416, 1443