JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster

We have used the multiobject mode of the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST) to obtain low-resolution 1–5 μ m spectra of 22 brown dwarf candidates in the Orion Nebula Cluster, which were selected with archival images from the Hubble Space Telescope. On...

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Main Authors: K. L. Luhman, C. Alves de Oliveira, I. Baraffe, G. Chabrier, E. Manjavacas, R. J. Parker, P. Tremblin
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad7b19
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author K. L. Luhman
C. Alves de Oliveira
I. Baraffe
G. Chabrier
E. Manjavacas
R. J. Parker
P. Tremblin
author_facet K. L. Luhman
C. Alves de Oliveira
I. Baraffe
G. Chabrier
E. Manjavacas
R. J. Parker
P. Tremblin
author_sort K. L. Luhman
collection DOAJ
description We have used the multiobject mode of the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST) to obtain low-resolution 1–5 μ m spectra of 22 brown dwarf candidates in the Orion Nebula Cluster, which were selected with archival images from the Hubble Space Telescope. One of the targets was previously classified as a Herbig–Haro (HH) object and exhibits strong emission in H i , H _2 , and the fundamental band of CO, further demonstrating that HH objects can have bright emission in that CO band. The remaining targets have late spectral types (M6.5 to early L) and are young based on gravity-sensitive features, as expected for low-mass members of the cluster. According to theoretical evolutionary models, these objects should have masses that range from the hydrogen burning limit to 0.003–0.007 M _⊙ . Two of the NIRSpec targets were identified as proplyds in earlier analysis of Hubble images. They have spectral types of M6.5 and M7.5, making them two of the coolest and least massive known proplyds. Another brown dwarf shows absorption bands at 3–5 μ m from ices containing H _2 O, CO _2 , OCN ^− , and CO, indicating that it is either an edge-on class II system or a class I protostar. It is the coolest and least massive object that has detections of these ice features. In addition, it appears to be the first candidate for a protostellar brown dwarf that has spectroscopy confirming its late spectral type.
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spelling doaj-art-19c7c1e5fffd42d090fa5eedd9bbc94e2025-08-20T01:47:21ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01975216210.3847/1538-4357/ad7b19JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula ClusterK. L. Luhman0https://orcid.org/0000-0003-2822-2951C. Alves de Oliveira1https://orcid.org/0000-0003-2896-4138I. Baraffe2https://orcid.org/0000-0001-8365-5982G. Chabrier3https://orcid.org/0000-0002-8342-9149E. Manjavacas4https://orcid.org/0000-0003-0192-6887R. J. Parker5https://orcid.org/0000-0002-1474-7848P. Tremblin6https://orcid.org/0000-0001-6172-3403Department of Astronomy and Astrophysics, The Pennsylvania State University , University Park, PA 16802, USA ; kll207@psu.edu; Center for Exoplanets and Habitable Worlds, The Pennsylvania State University , University Park, PA 16802, USAEuropean Space Agency, European Space Astronomy Centre , Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, SpainPhysics & Astronomy Department, University of Exeter, Exeter , EX4 4QL, UK; Ecole Normale Supérieure de Lyon , CRAL, CNRS UMR 5574, 69364, Lyon Cedex 07, FrancePhysics & Astronomy Department, University of Exeter, Exeter , EX4 4QL, UK; Ecole Normale Supérieure de Lyon , CRAL, CNRS UMR 5574, 69364, Lyon Cedex 07, FranceAURA for the European Space Agency, Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics & Astronomy, Johns Hopkins University , Baltimore, MD 21218, USADepartment of Physics and Astronomy, The University of Sheffield , Hicks Building, Hounsfield Road, Sheffield S3 7RH, UKUniversité Paris-Saclay , UVSQ, CNRS, CEA, Maison de la Simulation, 91191, Gif-sur-Yvette, FranceWe have used the multiobject mode of the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST) to obtain low-resolution 1–5 μ m spectra of 22 brown dwarf candidates in the Orion Nebula Cluster, which were selected with archival images from the Hubble Space Telescope. One of the targets was previously classified as a Herbig–Haro (HH) object and exhibits strong emission in H i , H _2 , and the fundamental band of CO, further demonstrating that HH objects can have bright emission in that CO band. The remaining targets have late spectral types (M6.5 to early L) and are young based on gravity-sensitive features, as expected for low-mass members of the cluster. According to theoretical evolutionary models, these objects should have masses that range from the hydrogen burning limit to 0.003–0.007 M _⊙ . Two of the NIRSpec targets were identified as proplyds in earlier analysis of Hubble images. They have spectral types of M6.5 and M7.5, making them two of the coolest and least massive known proplyds. Another brown dwarf shows absorption bands at 3–5 μ m from ices containing H _2 O, CO _2 , OCN ^− , and CO, indicating that it is either an edge-on class II system or a class I protostar. It is the coolest and least massive object that has detections of these ice features. In addition, it appears to be the first candidate for a protostellar brown dwarf that has spectroscopy confirming its late spectral type.https://doi.org/10.3847/1538-4357/ad7b19Brown dwarfsL dwarfsStar forming regionsInitial mass functionJames Webb Space TelescopeCircumstellar disks
spellingShingle K. L. Luhman
C. Alves de Oliveira
I. Baraffe
G. Chabrier
E. Manjavacas
R. J. Parker
P. Tremblin
JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
The Astrophysical Journal
Brown dwarfs
L dwarfs
Star forming regions
Initial mass function
James Webb Space Telescope
Circumstellar disks
title JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
title_full JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
title_fullStr JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
title_full_unstemmed JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
title_short JWST/NIRSpec Observations of Brown Dwarfs in the Orion Nebula Cluster
title_sort jwst nirspec observations of brown dwarfs in the orion nebula cluster
topic Brown dwarfs
L dwarfs
Star forming regions
Initial mass function
James Webb Space Telescope
Circumstellar disks
url https://doi.org/10.3847/1538-4357/ad7b19
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