Gaia Sausage

The "Gaia Sausage" is so-called because of the characteristic sausage shape of the population in a chart of velocity space, in particular a plot of radial (\boldsymbol{v}_r) versus azimuthal velocity (\boldsymbol{v}_\theta) of stars (see Spherical coordinate system), using data from the Gaia Mission. These stars had previously been seen in Hipparcos data and identified as originаting from an accreted galaxy. The name "Enceladus" refers to the mythological giant Enceladus, who was buried under Mount Etna and caused earthquakes. Similarly, this former galaxy was buried in the Milky Way, and caused the puffing up of the thick disc. ==Components==

Globular clusters The globular clusters firmly identified as former Sausage members are Messier 2, Messier 56, Messier 75, Messier 79, NGC 1851, NGC 2298, and NGC 5286. One theory to account for three generations of stars is that NGC 2808 is the former core of the Sausage. The "Gaia Sausage" reconstructed the Milky Way by puffing up the thin disk to make it a thick disk, whilst the gas it brought into the Milky Way triggered a fresh round of star formation and replenished the thin disk. The debris from the dwarf galaxy provides most of the metal-rich part of the galactic halo. ==See also==