Water deuteration in star-forming regions : Contribution of Herschel/HIFI spectroscopic data
type: Distribution
access URL: https://theses.hal.science/tel-00763292
format: HTML
issued: 2026-06-01T00:11:17.406968
modified: 2026-06-01T00:11:17.291051

test_moissonnage_selune
type: Agent

Water deuteration in star-forming regions : Contribution of Herschel/HIFI spectroscopic data
type: Dataset
contact point: Organization
  fn: CCSD
keyword: molecules-water
keyword: deuterated-water
keyword: theses
keyword: eau-deuteree
keyword: abondances
keyword: formation-stellaire
keyword: heterodyne-observations
keyword: infoeu-reposemanticsdoctoralthesis
keyword: herschelhifi
keyword: proto-etoiles-de-faible-masse
keyword: observations-heterodynes
keyword: low-mass-protostars
keyword: astrochemistry
keyword: milieu-interstellaire
keyword: star-formation
keyword: astrochimie
keyword: molecules-eau
keyword: sduastrsrsciences-of-the-universe-physicsastrophysics-astro-phsolar-and-stellar-astrophysi
keyword: physastrsrphysics-physicsastrophysics-astro-phsolar-and-stellar-astrophysics-astro-phsr
keyword: abundances
keyword: interstellar-medium
landing page: https://theses.hal.science/tel-00763292
description: Water (H2O) is one of the most abundant molecules in the interstellar medium. In addition to being a primordial ingredient in the emergence of life, this species plays an essential role in the process of star formation through the cooling of warm gas. It also controls the chemistry for many species, either in the gas phase or on the grain surfaces. Studying its deuterated form HDO is a unique opportunity, through the estimation of the HDO/H2O ratio, to constrain the mechanisms of water formation and to better understand the origin of water contained in terrestrial oceans. Indeed, recent results obtained with the Herschel satellite show that the HDO/H2O ratio observed in comets is similar to the value measured in oceans (~ 1.5 10-4), which suggests that comets could have brought a large fraction to Earth to form the oceans during heavy bombardments (Hartogh et al. 2011). In this thesis, I was interested in the study of deuterated water in the first stages of star formation, the Class 0 stage, which precede the formation of the protoplanetary disk leading to the birth of comets and planets. Through a 1D non-Local Thermodynamic Equilibrium radiative transfer modeling of the line profiles of the numerous HDO and H218O transitions detected with the HIFI (Heterodyne Instrument for Far-Infrared) instrument onboard the Herschel Space Observatory and ground-based telescopes (IRAM, JCMT), I determined that the HDO/H2O ratios of the solar-type protostar IRAS 16293-2422 was about 2% in the hot corino, the inner part of the protostellar envelope sufficiently warm (T > 100 K) to desorb in gas phase the water molecules trapped in the icy grain mantles, and about 0.5% in the colder part of the envelope. This study (Coutens et al. 2012) also allowed me to show that an absorbing layer rich in water surrounds the protostar. This layer could be produced by the photo-desorption through the UV field of the water molecules frozen on the grains, on the edges of the molecular cloud. The HDO…
issued: 2026-06-01T00:11:17.378095
language: fr
modified: 2026-06-01T00:11:17.378110