Astronomers are constantly working to figure out our place in space, and a new dataset helps get us a little closer to understanding how we fit in with the flow of stars in our galaxy. A new data release from the RAdial Velocity Experiment (RAVE) contains fifteen years of data tracing the motions and chemistry of 451,783 stars. This single project took advantage of almost every clear night in Siding Spring, Australia from 2003 to 2013 to obtain spectra using the 1.2m UK Schmidt telescope with a multi-fiber spectrograph that could observe up to 150 stars at a time. The data has been released in batches over time.
Yesterday, the RAVE collaboration put out their final data release. This is as good as it gets, and this data is now available to any researcher seeking to understand the structure and history of our galaxy. This data is described in a pair of papers in the Astronomical Journal with lead author Matthew Steinmetz.
Spectra take the light of stars and spread it out into a rainbow of color with dark and light bands that denote where specific atoms are absorbing and emitting light. The red and blue shifts in this light tell us how these stars’ distances from us are changing, either toward or away from us. They also tell us the stars’ compositions, allowing astronomers to look for ancient stars with fewer elements, and to trace out the bands of stars that once formed together from the same molecular clouds.
According to the press release: Some of the key results of RAVE include the determination of the minimum speed needed for a star to escape the gravitational pull of the Milky Way. The results confirmed that dark matter, an invisible component of the Universe of yet unknown nature, dominates the mass of our Galaxy. With RAVE it could be shown that the Milky Way disk is asymmetric and wobbles owing to the interaction with spiral arms and the infall of satellite galaxies. RAVE also allowed for the identification of stellar streams in the solar environment. These streams of stars are the residues of torn apart old dwarf galaxies that have merged into our Milky Way in the past.
This is an amazing data set. Earlier data releases have already led to more than a thousand research papers, and we look forward to seeing what new insights this latest release will bring.
“The Sixth Data Release of the Radial Velocity Experiment (RAVE). I. Survey Description, Spectra, and Radial Velocities,” Matthias Steinmetz et al., 2020 July 27, Astronomical Journal (Preprint on arxiv.org)
“The Sixth Data Release of the Radial Velocity Experiment (RAVE). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances,” Matthias Steinmetz et al., 2020 July 27, Astronomical Journal (Preprint on arxiv.org)