Journal article
Fundamental relations for the velocity dispersion of stars in the Milky Way
Monthly notices of the Royal Astronomical Society, Vol.506(2), pp.1761-1776
09/01/2021
DOI: 10.1093/mnras/stab1086
Abstract
We explore the fundamental relations governing the radial and vertical velocity dispersions of stars in the Milky Way, from combined studies of complementary surveys including GALAH, LAMOST, APOGEE, the NASA Kepler and K2 missions, and Gaia DR2. We find that different stellar samples, even though they target different tracer populations and employ a variety of age estimation techniques, follow the same set of fundamental relations. We provide the clearest evidence to date that, in addition to the well-known dependence on stellar age, the velocity dispersions of stars depend on orbital angular momentum L-z, metallicity, and height above the plane vertical bar z vertical bar, and are well described by a multiplicatively separable functional form. The dispersions have a power-law dependence on age with exponents of 0.441 +/- 0.007 and 0.251 +/- 0.006 for sigma(z) and sigma(R), respectively, and the power law is valid even for the oldest stars. For the solar neighbourhood stars, the apparent break in the power law for older stars, as seen in previous studies, is due to the anticorrelation of L-z with age. The dispersions decrease with increasing L-z until we reach the Sun's orbital angular momentum, after which sigma(z) increases (implying flaring in the outer disc) while sigma(R) flattens. For a given age, the dispersions increase with decreasing metallicity, suggesting that the dispersions increase with birth radius. The dispersions also increase linearly with vertical bar z vertical bar. The same set of relations that work in the solar neighbourhood also work for stars between 3 < R/kpc < 20. Finally, the high-[alpha/Fe] stars follow the same relations as the low-[alpha/Fe] stars.
Details
- Title: Subtitle
- Fundamental relations for the velocity dispersion of stars in the Milky Way
- Creators
- Sanjib Sharma - The University of SydneyMichael R. Hayden - The University of SydneyJoss Bland-Hawthorn - The University of SydneyDennis Stello - ARC Centre of Excellence for All-sky AstrophysicsSven Buder - ASTRO-3DJoel C. Zinn - UNSW SydneyThomas Kallinger - University of ViennaMartin Asplund - Max Planck Institute for AstrophysicsGayandhi M. De Silva - Macquarie UniversityValentina D'Orazi - INAF Osservatorio Astron Padova, I-35122 Padua, ItalyKen Freeman - Australian National UniversityJanez Kos - University of LjubljanaGeraint F. Lewis - The University of SydneyJane Lin - Australian National UniversityKarin Lind - Stockholm UniversitySarah Martell - UNSW SydneyJeffrey D. Simpson - UNSW SydneyRob A. Wittenmyer - University of Southern QueenslandDaniel B. Zucker - Macquarie UniversityTomaz Zwitter - University of LjubljanaBoquan Chen - The University of SydneyKlemen Cotar - University of LjubljanaJames Esdaile - UNSW SydneyMarc Hon - UNSW SydneyJonathan Horner - University of Southern QueenslandDaniel Huber - University of Hawaii SystemPrajwal R. Kafle - International Centre for Radio Astronomy ResearchShourya Khanna - The University of SydneyYuan-Sen Ting - Australian National UniversityDavid M. Nataf - Johns Hopkins UniversityThomas Nordlander - ARC Centre of Excellence for All-sky AstrophysicsMohd Hafiz Mohd Saadon - UNSW SydneyThor Tepper-Garcia - The University of SydneyC. G. Tinney - UNSW SydneyGregor Traven - Lund UniversityFred Watson - NSW Department of Planning and EnvironmentDuncan Wright - University of Southern QueenslandRosemary F. G. Wyse - Johns Hopkins University
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.506(2), pp.1761-1776
- DOI
- 10.1093/mnras/stab1086
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Publisher
- Oxford Univ Press
- Number of pages
- 16
- Grant note
- National Development and Reform Commission FL140100278; GRANTS:15529003 / Australian Research Council 2015-00415 3 / Swedish Research Council Chinese Academy of Sciences Alexander von Humboldt Foundation GRANTS:17227397; 2015-00415 / Vinnova INCA 600398 / Marie Sklodowska Curie Actions; Marie Curie Actions Allan C. and Dorothy H. Davis Fellowship FT1400147 / ARC Future Fellowship; Australian Research Council 2015-00415; GRANTS:17144642 / Swedish Research Council
- Language
- English
- Date published
- 09/01/2021
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984701831702771
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