2016/01/01 by O. Onal Tas, Özgecan Önal Taş, S. Bilir +6 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Galaxy #Metallicity #Milky Way #Physics #Radial velocity #Red clump #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1017/pasa.2016.33
18 pages, including 16 figures and 6 tables, accepted for publication in PASA
openalex publication_date 2016/01/01 · arxiv created 2016/07/24 · arxiv updated 2016/09/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract We investigate the Milky Way Galaxy’s radial and vertical metallicity gradients using a sample of 47 406 red clump stars from the RAdial Velocity Experiment Data Release 4. Distances are calculated by adopting K s -band absolute magnitude as −1.54±0.04 mag for the sample. The metallicity gradients are calculated with their current orbital positions ( R gc and Z ) and with their orbital properties ( R m and z max ): d[Fe/H]/d R gc = −0.047±0.003 dex kpc −1 for | Z | ≤ 0.5 kpc and d[Fe/H]/d R m = −0.025±0.002 dex kpc −1 for z max ≤ 0.5 kpc. This reaffirms the radial metallicity gradient in the thin disc but highlights that gradients are sensitive to the selection effects caused by the difference between R gc and R m . The radial gradient is flat in the distance interval 0.5-1 kpc from the plane and then becomes positive greater than 1 kpc from the plane. The radial metallicity gradients are also eccentricity dependent. We showed that d[Fe/H]/d R m = −0.089±0.010, −0.073±0.007, −0.053±0.004 and −0.044±0.002 dex kpc −1 for e p ≤ 0.05, e p ≤ 0.07, e p ≤ 0.10 and e p ≤ 0.20 sub-samples, respectively, in the distance interval z max ≤ 0.5 kpc. Similar trend is found for vertical metallicity gradients. Both the radial and vertical metallicity gradients are found to become shallower as the eccentricity of the sample increases. These findings can be used to constrain different formation scenarios of the thick and thin discs.