Characterization and retrieval of atmospheric parameters of terrestrial extrasolar planets around cool host stars

• Applicants: Professorin Dr. Heike Rauer; Dr. Franz Schreier
• Subject Area: Astrophysics and Astronomy
• Term: from 2015 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 282760199

• Final Report Year: 2021

Final Report Abstract

Regarding the 1D-TERRA model, this project has enabled the development of a world-class atmospheric photochemical module for use in exoplanetary science over a wide range of atmospheric compositions. The new chemical code was applied as part of this project to some select, habitable zone exoplanets and could be used in a first study to constrain atmospheric composition comparing with newly emerging data. Regarding atmospheric radiative transfer modeling we have used Earth observations for a thorough validation of our line-by-line code GARLIC and for an assessment of the importance and detectability of molecular species in infrared transmission spectra. For the retrieval of Earth-like exoplanetary temperature profiles from thermal infrared emission spectra we have developed a novel function expansion technique and used a standard nonlinear least squares solver in combination with our line-by-line forward model.

Publications

• Comments on the Voigt function implementation in the Astropy and SpectraPlot.com packages. JQSRT, 213:13–16, 2018
  F. Schreier
  (See online at https://doi.org/10.1016/j.jqsrt.2018.03.019)
• New insights into cosmic ray induced biosignature chemistry in Earth-like atmospheres. APJ, 863(1):6, 2018
  M. Scheucher, J. Grenfell, F. Wunderlich, M. Godolt, F. Schreier, and H. Rauer
  (See online at https://doi.org/10.3847/1538-4357/aacf03)
• The Voigt and complex error function: Humlicek’s rational approximation generalized. MNRAS, 479(3):3068–3075, 2018
  F. Schreier
  (See online at https://doi.org/10.1093/mnras/sty1680)
• Transmission spectroscopy with the ACE-FTS infrared spectral atlas of Earth: A model validation and feasibility study. Molec. Astrophysics, 11:1–22, 2018
  F. Schreier, S. Städt, P. Hedelt, and M. Godolt
  (See online at https://doi.org/10.1016/j.molap.2018.02.001)
• Detectability of atmospheric features of Earth-like planets in the habitable zone around M-dwarfs. A & A, 624:A49, 2019
  F. Wunderlich, M. Godolt, J. Grenfell, S. Städt, A. Smith, S. Gebauer, F. Schreier, P. Hedelt, and H. Rauer
  (See online at https://doi.org/10.1051/0004-6361/201834504)
• Consistently simulating a wide range of atmospheric scenarios for K2-18b with a flexible radiative transfer module. APJ, 898(1):44, 2020
  M. Scheucher, F. Wunderlich, J. L. Grenfell, M. Godolt, F. Schreier, D. Kappel, R. Haus, K. Herbst, and H. Rauer
  (See online at https://doi.org/10.3847/1538-4357/ab9084)
• Detectability of biosignatures on LHS1140b, Dec. 2020
  F. Wunderlich, M. Scheucher, M. Godolt, J. Grenfell, F. Schreier, and H. Rauer
  (See online at https://doi.org/10.1051/0004-6361/202039663)
• Distinguishing between wet and dry atmospheres of TRAPPIST-1 e and f. APJ, 901:126, 2020
  F. Wunderlich, M. Scheucher, M. Godolt, J. Grenfell, F. Schreier, P. Schneider, D. Wilson, A. Sanchez-Lopez, M. Lopez-Puertas, and H. Rauer
  (See online at https://doi.org/10.3847/1538-4357/aba59c)
• Possible atmospheric diversity of low mass exoplanets – some central aspects. Space Science Reviews, 216 (5), July 2020
  J. L. Grenfell, J. Leconte, F. Forget, M. Godolt, O. Carrion-Gonzalez, L. Noack, F. Tian, H. Rauer, F. Gaillard, E. Bolmont, B. Charnay, and M. Turbet
  (See online at https://doi.org/10.1007/s11214-020-00716-4)
• SVEEEETIES – singular vector expansion to estimate Earth-like exoplanet temperatures from infrared emission spectra. A & A, 633:A156, 2020
  F. Schreier, S. Städt, F. Wunderlich, M. Godolt, and J. Grenfell
  (See online at https://doi.org/10.1051/0004-6361/201936511)