Information on the Milky Way from the 2mass all sky star count: Bimodal color distributions

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/100889

Title:	Information on the Milky Way from the 2mass all sky star count: Bimodal color distributions
Authors:	高仲明;Chang, Chan-Kao;Lai, Shao-Yu;Ko, Chung-Ming;Peng, Ting-Hung
Contributors:	理學院天文研究所
Keywords:	ASTRONOMY;ASTROPHYSICS;ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;COLOR;Counting;Disks;Empirical analysis;HERTZSPRUNG-RUSSELL DIAGRAM;Latitude;LUMINOSITY;MAIN SEQUENCE STARS;MASS;MILKY WAY;NEAR INFRARED RADIATION;Sky;Stellar age
Date:	2012-11-10
Issue Date:	2026-04-21 14:17:30 (UTC+8)
Publisher:	IOP Publishing Ltd.;United States
Abstract:	摘要： The J-K sub(s) color distributions (CDs) with a bin size of 0.05 mag has been carried out for the entire Milky Way using the Two Micron All Sky Survey Point Source Catalog (2MASS PSC). The CDs are bimodal, with a red peak at 0.8 < J-K sub(s) < 0.85 and a blue peak at 0.3 < J-K sub(s) < 0.4. The colors of the red peak are more or less the same for the whole sky, but those of the blue peak depend on Galactic latitude (J-K sub(s) ~ 0.35 at low Galactic latitudes and 0.35 < J-K sub(s) < 0.4 for other sky areas). The blue peak dominates the bimodal CDs at low Galactic latitudes and becomes comparable with the red peak in other sky regions. In order to explain the bimodal distribution and the global trend shown by the all-sky 2MASS CDs, we assemble an empirical Hertzsprung-Russell (H-R) diagram, which is composed of observational-based near-infrared H-R diagrams and color-magnitude diagrams, and incorporate a MilkyWay model. In the empirical H-R diagram, the main-sequence turn-off for stars in the thin disk is relatively bluer, (J-K sub(s)) sub(0) = 0.31, compared with that of the thick disk which is (J-K sub(s)) sub(0) = 0.39. The age of the thin/thick disk is roughly estimated to be around 4-5/8-9 Gyr according to the color-age relation of the main-sequence turn-off. In general, the 2MASS CDs can be treated as a tool to measure the age of the stellar population of the Milky Way in a statistical manner and to our knowledge it is the first attempt to do so. 出版者： United States 出版日期： 2012-11-10 出處： The Astrophysical journal, 2012-11, Vol.759 (2), p.1-10 資源來源： Institute of Physics Journals 識別號： ISSN: 0004-637X 識別號： EISSN: 1538-4357 識別號： DOI: 10.1088/0004-637X/759/2/94
Appears in Collections:	[Graduate Institute of Astronomy] journal & Dissertation

Files in This Item:

File	Description	Size	Format
index.html		0Kb	HTML	18	View/Open

社群 sharing

Loading...