Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-06-20
Nature450:1020-1025,2007
Astronomy and Astrophysics
Astrophysics
Two stand-alone files in manuscript, concatenated together. The first is for the main paper, the second for supplementary info
Scientific paper
10.1038/nature06460
The halo of the Milky Way provides unique elemental abundance and kinematic information on the first objects to form in the Universe, which can be used to tightly constrain models of galaxy formation and evolution. Although the halo was once considered a single component, evidence for its dichotomy has slowly emerged in recent years from inspection of small samples of halo objects. Here we show that the halo is indeed clearly divisible into two broadly overlapping structural components -- an inner and an outer halo -- that exhibit different spatial density profiles, stellar orbits and stellar metallicities (abundances of elements heavier than helium). The inner halo has a modest net prograde rotation, whereas the outer halo exhibits a net retrograde rotation and a peak metallicity one-third that of the inner halo. These properties indicate that the individual halo components probably formed in fundamentally different ways, through successive dissipational (inner) and dissipationless (outer) mergers and tidal disruption of proto-Galactic clumps.
Bailer-Jones Coryn A. L.
Beers Timothy C.
Carollo Daniela
Chiba Masashi
Lee Young Sam
No associations
LandOfFree
Two Stellar Components in the Halo of the Milky Way does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Two Stellar Components in the Halo of the Milky Way, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two Stellar Components in the Halo of the Milky Way will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-34526