Self-consistent grain depletions and abundances I: the Orion Nebula as a test case

Chamani M. Gunasekera, Xihan Ji, Marios Chatzikos, Renbin Yan, Gary Ferland

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Atomic species in the interstellar medium transition out of their gas phase mainly by depletion on to dust. In this study, we examine if there is any change to the spectral-line ratio predictions from a photoionization model of the Orion H ii region when the degree of dust depletions is altered according to the most recently published model. We use equations and parameters published by previous works, in order to streamline the calculation of depleted abundances within cloudy. Our aim is for cloudy users to be able to vary the level of depletion using a single parameter in the input file. This makes it possible to explore predictions for a large range of depletions more efficiently. Finally, we discuss the results obtained for a model of the Orion Nebula when the degree of depletions are manipulated in this way. We found that the intensity of line ratios are significantly affected by depletions on to dust grains. Further, we found that adjusting dust abundances along with depletion affects the structure and the overall temperature of the H+ layer across the H ii region.

Original languageEnglish
Pages (from-to)2310-2317
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - May 1 2022

Bibliographical note

Funding Information:
We thank all the people that have made this paper possible. This includes but not limited to the published work of Hensley & Draine ( 2021 ). CMG was supported by Space Telescope Science Institute (STScI, HST-AR-15018 and HST-GO-16196.003-A). MC acknowledges support by National Science Foundation (NSF, 1910687), National Aeronautics and Space Administration (NASA, 19-ATP19-0188), and STScI (HST-AR-14556.001-A). GF acknowledges support by NSF (1816537, 1910687), NASA (A TP 17-A TP17-0141, 19-ATP19-0188), and STScI (HST-AR-15018 and HST-GO-16196.003-A).

Publisher Copyright:
© 2022 The Author(s).


  • H ii regions
  • ISM: abundances
  • ISM: atoms
  • dust, extinction
  • ultraviolet: ISM

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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