What the study found
The study found that element abundance gradients in stars can be used to empirically measure the Milky Way’s circular velocity curve. Using APOGEE stellar abundances and Gaia kinematics, the authors report a circular velocity at the solar radius of 235.3 km s−1, along with measurements of related orbital frequencies and kinematic quantities.
Why the authors say this matters
The authors conclude that this data-driven method uses the Galaxy’s radial orbit structure to measure the circular velocity curve, epicyclic frequency, azimuthal frequency, and kinematic gradients across the Milky Way’s disk. The findings indicate that average [Fe/H] and [Mg/Fe] abundance ratios trace different aspects of stellar disk structure.
What the researchers tested
The researchers developed a new data-driven method that uses element abundance gradients in the plane of radial kinematics. They combined stellar surface abundances from the APOGEE survey with kinematic data from the Gaia mission and analyzed [Fe/H] and [Mg/Fe] abundance ratios.
What worked and what didn't
The results confirm ordered structure in the Milky Way’s disk in terms of mean [Fe/H] and [Mg/Fe]. The study suggests that 〈[Fe/H]〉 traces the radial positions of stars in the disk, while 〈[Mg/Fe]〉 traces orbital excursions around that radius. Using [Mg/Fe], the authors infer a solar-radius circular velocity of 235.3 km s−1, radial frequency of 36.9 km s−1 kpc−1, azimuthal frequency of 28.5 km s−1 kpc−1, and Oort constants A = 16.5 km s−1 kpc−1 and B = −11.9 km s−1 kpc−1.
What to keep in mind
The abstract does not describe detailed limitations beyond the scope of the method and the specific measurements reported. The reported values are tied to the solar radius and to the abundance ratios used in this analysis.
Key points
- Element abundance gradients were used to measure the Milky Way’s circular velocity curve.
- The study used APOGEE stellar abundances together with Gaia kinematic data.
- The inferred circular velocity at the solar radius was 235.3 km s−1 using [Mg/Fe].
- [Fe/H] was reported to trace radial positions, while [Mg/Fe] traced orbital excursions around that radius.
- The authors also measured radial and azimuthal frequencies and derived Oort constants.
Disclosure
- Research title:
- Milky Way circular velocity measured from stellar abundances
- Publication date:
- 2026-03-10
- OpenAlex record:
- View
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