Unveiling the Milky Way with a Gaia DR3 census of OB-type stars within 2 kpc. I. Tracing local Galactic structure, massive star-forming regions and core-collapse supernova progenitors
Abstract
O- and B-type stars are young and hot, thereby serving as vital tracers of the star formation and spiral arm structure of the Milky Way. At the dusk of the \textit{Gaia} DR3 era, a high-confidence and accurate catalogue appears timely. We have characterized 105,971 OB-type stars (Teff > 10,000 K) within 2 kpc from the Sun, using an astro-photometric Bayesian inference tool. Our map unveils a complex view of the young stellar populations across the thin disk, with prominent large-scale features such as the Cepheus Spur, the Giant Oval Cavity, and a segment the Sagittarius-Carina arm all visible. Their inhomogeneous spatial distribution implies that massive star formation has taken place clustered across a few highly concentrated regions. We find a correlation between the overdensities of OB-type stars and young open clusters, and attribute departure from it to extinction effects. We identify 4200 stars as model-dependent core-collapse supernova (ccSN) or direct-collapse black hole (BH) progenitor candidates, including 6 ccSN progenitor candidates within 125 pc -- the maximum radius within which a ccSN explosion could be harmful to Earth's biosphere -- but our analysis suggests none of them exploding within the next 5 Myrs. Finally, we anticipate more evolved OB-type stars to collapse to form BHs within the next 1 Myr than ccSN progenitors will explode, despite the former's much scarcer number. A possible interpretation is a recent star formation burst in the local Milky Way, consistent with overdensities of ccSN progenitor candidates in Cyg OB2 and the Sagittarius-Carina arm.
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BibTeX
@misc{quintana2026unveiling,
title = {{Unveiling the Milky Way with a Gaia DR3 census of OB-type stars within 2 kpc. I. Tracing local Galactic structure, massive star-forming regions and core-collapse supernova progenitors}},
author = {Alexis L. Quintana and Kiril Maltsev and Eloisa Poggio and Emily L. Hunt and Nicholas J. Wright and Sara R. Berlanas and Laia Casamiquela and Abel de Burgos and Hanna Parul and Misha Haywood and Paola Di Matteo and Chervin Laporte and Juan Martínez García},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.07068},
eprint = {2607.07068},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.07068},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Unveiling the Milky Way with a Gaia DR3 census of OB-type stars within 2 kpc. I. Tracing local Galactic structure, massive star-forming regions and core-collapse supernova progenitors
AU - Alexis L. Quintana
AU - Kiril Maltsev
AU - Eloisa Poggio
AU - Emily L. Hunt
AU - Nicholas J. Wright
AU - Sara R. Berlanas
AU - Laia Casamiquela
AU - Abel de Burgos
AU - Hanna Parul
AU - Misha Haywood
AU - Paola Di Matteo
AU - Chervin Laporte
AU - Juan Martínez García
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2607.07068
UR - https://arxiv.org/abs/2607.07068
AB - O- and B-type stars are young and hot, thereby serving as vital tracers of the star formation and spiral arm structure of the Milky Way. At the dusk of the \textit{Gaia} DR3 era, a high-confidence and accurate catalogue appears timely. We have characterized 105,971 OB-type stars (T_eff > 10,000 K) within 2 kpc from the Sun, using an astro-photometric Bayesian inference tool. Our map unveils a complex view of the young stellar populations across the thin disk, with prominent large-scale features such as the Cepheus Spur, the Giant Oval Cavity, and a segment the Sagittarius-Carina arm all visible. Their inhomogeneous spatial distribution implies that massive star formation has taken place clustered across a few highly concentrated regions. We find a correlation between the overdensities of OB-type stars and young open clusters, and attribute departure from it to extinction effects. We identify 4200 stars as model-dependent core-collapse supernova (ccSN) or direct-collapse black hole (BH) progenitor candidates, including 6 ccSN progenitor candidates within 125 pc -- the maximum radius within which a ccSN explosion could be harmful to Earth's biosphere -- but our analysis suggests none of them exploding within the next 5 Myrs. Finally, we anticipate more evolved OB-type stars to collapse to form BHs within the next 1 Myr than ccSN progenitors will explode, despite the former's much scarcer number. A possible interpretation is a recent star formation burst in the local Milky Way, consistent with overdensities of ccSN progenitor candidates in Cyg OB2 and the Sagittarius-Carina arm.
ER -