Large-Scale Spiral Structure of the Milky Way Traced by Young Classical Cepheids
Abstract
Using 985 classical Cepheids younger than 100 Myr, we investigate the large-scale spiral structure of the Milky Way by comparing their spatial and kinematic distributions with the R19 (four-arm) and X23 (multiple-arm) spiral-arm models. Both models provide reasonably good descriptions of the current sample: R19 yields slightly smaller point-to-arm distances, whereas X23 has a higher supported-arm fraction, but the descriptive statistics do not provide a decisive preference between them. Model-dependent arm assignment and refitting suggest that the distribution of the youngest Classical Cepheids (20--60 Myr) is consistent with an X23-like multiple-arm in which the Perseus and Norma arms form two dominant inner arms extending toward the ends of the Galactic bar, the Sagittarius and Centaurus segments are possible branches of these inner arms, and Local, Outer, and other features constitute additional arm segments. The updated model improves the constraints on the southern spiral structure, yielding smaller point-to-arm distances and a higher supported-arm fraction. Some of these structures extend to heliocentric distances of approximately 15~kpc.
Related
- The Flare and Spiral Structure of the Milky Way’s Disk as Traced by Young Giant Stars
- VELOcities of CEpheids (VELOCE) III. Reconstructing radial velocity curves of classical Cepheids
- Interstellar extinction of classical Cepheids from neighboring stars. I. Methodology and application to 16 Galactic Cepheids
- Interstellar extinction of classical Cepheids from neighboring stars I. Methodology and application to 16 Galactic Cepheids
- Classical Cepheids in the Nuclear Stellar Disk: membership via dynamical analysis
BibTeX
@misc{lin2026largescale,
title = {{Large-Scale Spiral Structure of the Milky Way Traced by Young Classical Cepheids}},
author = {Z. H. Lin and C. J. Hao and D. J. Liu and Y. J. Li and J. J. Li and Y. W. Dong and Y. X. He and Jarken Esimbek},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.34208},
eprint = {2609.34208},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.34208},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Large-Scale Spiral Structure of the Milky Way Traced by Young Classical Cepheids
AU - Z. H. Lin
AU - C. J. Hao
AU - D. J. Liu
AU - Y. J. Li
AU - J. J. Li
AU - Y. W. Dong
AU - Y. X. He
AU - Jarken Esimbek
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.34208
UR - https://arxiv.org/abs/2609.34208
AB - Using 985 classical Cepheids younger than 100 Myr, we investigate the large-scale spiral structure of the Milky Way by comparing their spatial and kinematic distributions with the R19 (four-arm) and X23 (multiple-arm) spiral-arm models. Both models provide reasonably good descriptions of the current sample: R19 yields slightly smaller point-to-arm distances, whereas X23 has a higher supported-arm fraction, but the descriptive statistics do not provide a decisive preference between them. Model-dependent arm assignment and refitting suggest that the distribution of the youngest Classical Cepheids (20--60 Myr) is consistent with an X23-like multiple-arm in which the Perseus and Norma arms form two dominant inner arms extending toward the ends of the Galactic bar, the Sagittarius and Centaurus segments are possible branches of these inner arms, and Local, Outer, and other features constitute additional arm segments. The updated model improves the constraints on the southern spiral structure, yielding smaller point-to-arm distances and a higher supported-arm fraction. Some of these structures extend to heliocentric distances of approximately 15~kpc.
ER -