PDRs4All: III. JWST's NIR spectroscopic view of the Orion Bar
Artikel i vetenskaplig tidskrift, 2024

Context. JWST has taken the sharpest and most sensitive infrared (IR) spectral imaging observations ever of the Orion Bar photodis-sociation region (PDR), which is part of the nearest massive star-forming region the Orion Nebula, and often considered to be the 'prototypical'strongly illuminated PDR.

Aims. We investigate the impact of radiative feedback from massive stars on their natal cloud and focus on the transition from the H II region to the atomic PDR -crossing the ionisation front (IF) -, and the subsequent transition to the molecular PDR -crossing the dissociation front (DF). Given the prevalence of PDRs in the interstellar medium and their dominant contribution to IR radiation, understanding the response of the PDR gas to far-ultraviolet (FUV) photons and the associated physical and chemical processes is fundamental to our understanding of star and planet formation and for the interpretation of any unresolved PDR as seen by JWST.

Methods. We used high-resolution near-IR integral field spectroscopic data from NIRSpec on JWST to observe the Orion Bar PDR as part of the PDRs4All JWST Early Release Science programme. We constructed a 3″ × 25″ spatio-spectral mosaic covering 0.97-5.27 μm at a spectral resolution R of ~2700 and an angular resolution of 0.075″-0.173″. To study the properties of key regions captured in this mosaic, we extracted five template spectra in apertures centred on the three H2 dissociation fronts, the atomic PDR, and the H II region. This wealth of detailed spatial-spectral information was analysed in terms of variations in the physical conditions-incident UV field, density, and temperature -of the PDR gas.

Results. The NIRSpec data reveal a forest of lines including, but not limited to, He I, H I, and C I recombination lines; ionic lines (e.g. Fe III and Fe II); O I and N I fluorescence lines; aromatic infrared bands (AIBs, including aromatic CH, aliphatic CH, and their CD counterparts); pure rotational and ro-vibrational lines from H2; and ro-vibrational lines from HD, CO, and CH+, with most of them having been detected for the first time towards a PDR. Their spatial distribution resolves the H and He ionisation structure in the Huygens region, gives insight into the geometry of the Bar, and confirms the large-scale stratification of PDRs. In addition, we observed numerous smaller-scale structures whose typical size decreases with distance from θ1 Ori C and IR lines from C I, if solely arising from radiative recombination and cascade, reveal very high gas temperatures (a few 1000 K) consistent with the hot irradiated surface of small-scale dense clumps inside the PDR. The morphology of the Bar, in particular that of the H2 lines, reveals multiple prominent filaments that exhibit different characteristics. This leaves the impression of a 'terraced'transition from the predominantly atomic surface region to the CO-rich molecular zone deeper in. We attribute the different characteristics of the H2 filaments to their varying depth into the PDR and, in some cases, not reaching the C+/C/CO transition. These observations thus reveal what local conditions are required to drive the physical and chemical processes needed to explain the different characteristics of the DFs and the photochemical evolution of the AIB carriers.

Conclusions. This study showcases the discovery space created by JWST to further our understanding of the impact radiation from young stars has on their natal molecular cloud and proto-planetary disk, which touches on star and planet formation as well as galaxy evolution.

HII regions

Techniques: spectroscopic

Infrared: ISM

ISM: individual objects: Orion Bar

Photon-dominated region (PDR)

Författare

Els Peeters

Western University

SETI Institute

Emilie Habart

Institut d'Astrophysique Spatiale

O. Berné

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Ameek Sidhu

Western University

Ryan Chown

Western University

Dries Van De Putte

Space Telescope Science Institute (STScI)

Boris Trahin

Institut d'Astrophysique Spatiale

Ilane Schroetter

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Amelie Canin

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Felipe Alarcon

University of Michigan

Bethany Schefter

Western University

Baria Khan

Western University

Sofia Pasquini

Western University

A.G.G.M. Tielens

Universiteit Leiden

University of Maryland

M.G. Wolfire

University of Maryland

E. Dartois

Université Paris-Saclay

J.R. Goicoechea

CSIC - Instituto de Fisica Fundamental (IFF)

Alexandros Maragkoudakis

NASA Ames Research Center

Takashi Onaka

University of Tokyo

Meisei University

Marc W. Pound

University of Maryland

S. Vicente

Instituto de Astrofísica e Ciências do Espaço (IA)

Alain Abergel

Institut d'Astrophysique Spatiale

E. A. Bergin

University of Michigan

J. Bernard-Salas

CERGA (Centre d'Etudes et de Recherche de Grasse ACRI)

Innovative Common Laboratory For Space Spectroscopy (INCLASS)

Christiaan Boersma

NASA Ames Research Center

E. Bron

Observatoire de Paris

Jan Cami

Western University

S. Cuadrado

CSIC - Instituto de Fisica Fundamental (IFF)

D. Dicken

Royal Observatory

Meriem Elyajouri

Institut d'Astrophysique Spatiale

A. Fuente

Observatorio Astronómico Nacional (OAN)

K. Gordon

Space Telescope Science Institute (STScI)

Universiteit Gent

Lina Issa

Institut de Recherche en Astrophysique et Planétologie (IRAP)

C. Joblin

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Olga Kannavou

Institut d'Astrophysique Spatiale

Ozan Lacinbala

Quantum Solid State Physics (QSP)

David Languignon

Observatoire de Paris

R. Le Gal

Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)

Institut de Radioastronomie Millimétrique (IRAM)

Raphael Meshaka

Institut d'Astrophysique Spatiale

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

Yoko Okada

Universität zu Köln

Massimo Robberto

Space Telescope Science Institute (STScI)

Johns Hopkins University

M. Rollig

Johann Wolfgang Goethe Universität Frankfurt am Main

Physikalischer Verein

Thiébaut-Antoine Schirmer

Institut d'Astrophysique Spatiale

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Benoît Tabone

Institut d'Astrophysique Spatiale

Marion Zannese

Institut d'Astrophysique Spatiale

I. Aleman

Universidade Federal de Itajuba

Universidade de Sao Paulo (USP)

Louis Allamandola

Bay Area Environmental Research Institute (BAER)

NASA Ames Research Center

Rebecca Auchettl

Australian Synchrotron (ANSTO)

Giuseppe Antonio Baratta

Istituto nazionale di astrofisica (INAF)

Salma Bejaoui

NASA Ames Research Center

Partha P. Bera

Bay Area Environmental Research Institute (BAER)

NASA Ames Research Center

John H Black

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

F. Boulanger

Laboratoire de Physique de l’Ecole Normale Supérieure

Jordy Bouwman

University of Colorado at Boulder

B. R. Brandl

Delft University of Technology

Universiteit Leiden

Philippe Brechignac

Université Paris-Saclay

S. Brünken

Radboud Universiteit

Mridusmita Buragohain

University of Hyderabad

Andrew Burkhardt

Wellesley College

Alessandra Candian

Anton Pannekoek Institute for Astronomy

S. Cazaux

TU Delft

Jose Cernicharo

CSIC - Instituto de Fisica Fundamental (IFF)

Marin Chabot

Université Paris-Saclay

Shubhadip Chakraborty

Gitam School of Science

Université de Rennes 1

Jason Champion

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Sean W. J. Colgan

NASA Ames Research Center

Ilsa R. Cooke

University of British Columbia (UBC)

A. Coutens

Institut de Recherche en Astrophysique et Planétologie (IRAP)

N. L. J. Cox

Observatoire de la Cote d'Azur

ACRI-ST

K. Demyk

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Jennifer Donovan Meyer

National Radio Astronomy Observatory

Sacha Foschino

Institut de Recherche en Astrophysique et Planétologie (IRAP)

P. Garcia-Lario

European Space Astronomy Centre (ESAC)

M. Gerin

Observatoire de Paris

C. A. Gottlieb

Harvard-Smithsonian Center for Astrophysics

P. Guillard

Institut d 'Astrophysique de Paris

Institut Universitaire de France

Antoine Gusdorf

Laboratoire de Physique de l’Ecole Normale Supérieure

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

Patrick Hartigan

Rice University

J. H. He

Universidad de Chile (UCH)

Yunnan Observatories

Chinese Academy of Sciences

E Herbst

University of Virginia

Liv Hornekaer

Aarhus Universitet

Cornelia Jäger

Friedrich-Schiller-Universität Jena

Eduardo Janot-Pacheco

Universidade de Sao Paulo (USP)

M. Kaufman

San Jose State University

S. Kendrew

Europeiska rymdorganisationen (ESA)

M. S. Kirsanova

Russian Academy of Sciences

Pamela Klaassen

Royal Observatory

Sun Kwok

University of British Columbia (UBC)

A. Labiano

European Space Astronomy Centre (ESAC)

Thomas Lai

California Institute of Technology (Caltech)

Timothy J. Lee

NASA Ames Research Center

B. Lefloch

Université de Bordeaux

Franck Le Petit

Observatoire de Paris

Aigen Li

University of Missouri

H. Linz

Max-Planck-Gesellschaft

Cameron J. MacKie

Lawrence Berkeley National Laboratory

University of California at Berkeley

S. C. Madden

Université Paris-Saclay

Joëlle Mascetti

Institut des Sciences Moleculaires, Talence

Brett McGuire

National Radio Astronomy Observatory

Massachusetts Institute of Technology (MIT)

Pablo Merino

CSIC - Instituto de Ciencia de Materiales de Madrid (ICMM)

Elisabetta R. Micelotta

Helsingin Yliopisto

K. A. Misselt

University of Arizona

Jon A. Morse

AstronetX

Giacomo Mulas

Istituto nazionale di astrofisica (INAF)

Institut de Recherche en Astrophysique et Planétologie (IRAP)

Naslim Neelamkodan

United Arab Emirates University

Ryou Ohsawa

National Astronomical Observatory of Japan

R. Paladini

California Institute of Technology (Caltech)

Maria Elisabetta Palumbo

Istituto nazionale di astrofisica (INAF)

Amit Pathak

Banaras Hindu University

Yvonne J. Pendleton

University of Central Florida

Annemieke Petrignani

Universiteit Van Amsterdam

Thomas Pino

Université Paris-Saclay

E. Puga

Europeiska rymdorganisationen (ESA)

Naseem Rangwala

NASA Ames Research Center

Mathias Rapacioli

UMR5626

Alessandra Ricca

SETI Institute

J. Roman-Duval

Space Telescope Science Institute (STScI)

Joseph Roser

NASA Ames Research Center

SETI Institute

Evelyne Roueff

Observatoire de Paris

Gaël Rouillé

Friedrich-Schiller-Universität Jena

Farid Salama

NASA Ames Research Center

Dinalva A. Sales

Estatística e Física

Karin Sandstrom

University of California

Peter Sarre

University of Nottingham

Ella Sciamma-O'Brien

NASA Ames Research Center

Kris Sellgren

Ohio State University

Sachindev S. Shenoy

Space Science Institute

D. Teyssier

European Space Astronomy Centre (ESAC)

Richard D. Thomas

Stockholms universitet

Aditya Togi

Texas State University

Laurent Verstraete

Institut d'Astrophysique Spatiale

Adolf N. Witt

University of Toledo

A. Wootten

National Radio Astronomy Observatory

Nathalie Ysard

Institut d'Astrophysique Spatiale

H. Zettergren

Stockholms universitet

Yong Zhang

Sun Yat-Sen University

Ziwei E. Zhang

RIKEN

Junfeng Zhen

Deep Space Exploration Laboratory (DSEL)

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 685 A74

Ämneskategorier

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

DOI

10.1051/0004-6361/202348244

Mer information

Senast uppdaterat

2024-08-19