First L-type substellar object discovered in the vicinity of the embedded cluster NGC 2023
Abstract
We present the first substellar object in a star-forming region spectroscopically confirmed with Euclid, namely J054158.70-021031.4. This young and faint source is located close to the embedded open cluster NGC 2023. It has a spectral type of L3, a reddening of Av = 3 mag, proper motion consistent with the nearby cluster NGC 2024, and a magnitude of ∼24.5 in the Euclid optical band. At the distance of 403 pc, its inferred mass lies close to the planetary-mass boundary. We discovered the object by searching for ultracool dwarf candidates in the Euclid Early Release Observations. The search was based on photometric criteria, followed by the analysis of slitless 2D spectro-images in order to distinguish features that indicate the nature of these objects. This work demonstrates the potential of Euclid to unveil previously hidden populations of very low-mass objects, located in obscured regions where star formation is ongoing.
Versions
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BibTeX
@misc{tsilia2026first,
title = {{First L-type substellar object discovered in the vicinity of the embedded cluster NGC 2023}},
author = {Styliani Tsilia and Carlos Dominguez-Tagle and Maruša Žerjal and Eduardo L. Martín and Hervé Bouy and Nafise Sedighi and Sara Muñoz Torres and Nikola Vitas and Khalid Barkaoui and Nicolas Lodieu and Jerry J. -Y. Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19009},
eprint = {2610.19009},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19009},
}
RIS
TY - UNPB
TI - First L-type substellar object discovered in the vicinity of the embedded cluster NGC 2023
AU - Styliani Tsilia
AU - Carlos Dominguez-Tagle
AU - Maruša Žerjal
AU - Eduardo L. Martín
AU - Hervé Bouy
AU - Nafise Sedighi
AU - Sara Muñoz Torres
AU - Nikola Vitas
AU - Khalid Barkaoui
AU - Nicolas Lodieu
AU - Jerry J. -Y. Zhang
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.19009
UR - https://arxiv.org/abs/2610.19009
AB - We present the first substellar object in a star-forming region spectroscopically confirmed with Euclid, namely J054158.70-021031.4. This young and faint source is located close to the embedded open cluster NGC 2023. It has a spectral type of L3, a reddening of Av = 3 mag, proper motion consistent with the nearby cluster NGC 2024, and a magnitude of ∼24.5 in the Euclid optical band. At the distance of 403 pc, its inferred mass lies close to the planetary-mass boundary. We discovered the object by searching for ultracool dwarf candidates in the Euclid Early Release Observations. The search was based on photometric criteria, followed by the analysis of slitless 2D spectro-images in order to distinguish features that indicate the nature of these objects. This work demonstrates the potential of Euclid to unveil previously hidden populations of very low-mass objects, located in obscured regions where star formation is ongoing.
ER -