GALAH
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The Galactic Archaeology with HERMES (GALAH) project uses the HERMES spectrograph on the Anglo-Australian Telescope at Australian National University to measure stellar parameters and abundances of more than 900,000 stars, including repeat observations of 50,000. HERMES measures high-resolution (R~28,000) spectra of 400 stars at a time.
Data Release 4 (DR4) is the most recent public release of GALAH. DR4 includes the following data for each of 917,588 stars in the Milky Way, in the survey area shown below:
- Reduced one-dimensional spectra across the four wavelength regions of the HERMES spectrograph, from about 4700 to 7900 Ångstroms
- Barycentric radial velocity, including secondary stars in binary systems
- Stellar parameters including effective temperature, surface gravity, iron abundance, microturbulence, and broadening
- Up to 30 elemental abundances per star, including
- light elements: Li, C, N, O
- odd-Z elements: Na, Al, K
- α-elements: Mg, Si, Ca, Ti
- iron-peak elements: Sc, V, Cr, Mn, Co, Ni, Cu, Zn
- light and heavy slow neutron capture elements: Rb, Sr, Y, Zr, Mo, Ba, La, Ce, Nd
- rapid neutron capture elements: Ru, Sm, Eu
- Three value-added catalogues:
- Galactic orbital properties
- Crossmatches to Gaia DR3, 2MASS, and WISE with the contents of those catalogs
- 3D NLTE lithium abundances
For more details about the data, see the GALAH Data Release 4 website.