2005/02/04 by Shogo Nishiyama, Tetsuya Nagata, Daisuke Baba +18 · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/429291
published as Astrophys.J. 621 (2005) L105-L108 · 8 pages, 4 figures. accepted by ApJL
arxiv created 2005/02/04 · openalex publication_date 2005/02/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
We present the result of a near-infrared ( JHK s ) survey along the Galactic plane, -10 5 ≤ l ≤ 10 5 and b = +1°, with the IRSF 1.4 m telescope and the SIRIUS camera. K s versus H - K s color-magnitude diagrams reveal a well-defined population of red clump stars whose apparent magnitude peak changes continuously along the Galactic plane, from K s = 13.4 at l = -10° to K s = 12.2 at l = 10° after dereddening. This variation can be explained by the barlike structure found in previous studies, but we find an additional inner structure at ∣ l ∣ ≲ 4°, where the longitude-apparent magnitude relation is distinct from the outer bar and where the apparent magnitude peak changes by only ≈0.1 mag over the central 8°. The exact nature of this inner structure is as yet uncertain.