Abstract
One of the long-standing problems in modern astronomy is the curious division of Galactic globular clusters, the "Oosterhoff dichotomy," according to the properties of their RR Lyrae stars. Here, we find that most of the lowest metallicity ([Fe/H] < -2.0) clusters, which are essential to an understanding of this phenomenon, display a planar alignment in the outer halo. This alignment, combined with evidence from kinematics and stellar population, indicates a captured origin from a satellite galaxy. We show that, together with the horizontal-branch evolutionary effect, the factor producing the dichotomy could be a small time gap between the cluster-formation epochs in the Milky Way and the satellite. The results oppose the traditional view that the metal-poorest clusters represent the indigenous and oldest population of the Galaxy.
| Original language | English |
|---|---|
| Pages (from-to) | 578-581 |
| Number of pages | 4 |
| Journal | Science |
| Volume | 297 |
| Issue number | 5581 |
| DOIs | |
| Publication status | Published - 2002 Jul 26 |
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All Science Journal Classification (ASJC) codes
- General
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An aligned stream of low-metallicity clusters in the halo of the milky way. / Yoon, Suk J.; Lee, Young Wook.
In: Science, Vol. 297, No. 5581, 26.07.2002, p. 578-581.Research output: Contribution to journal › Article
TY - JOUR
T1 - An aligned stream of low-metallicity clusters in the halo of the milky way
AU - Yoon, Suk J.
AU - Lee, Young Wook
PY - 2002/7/26
Y1 - 2002/7/26
N2 - One of the long-standing problems in modern astronomy is the curious division of Galactic globular clusters, the "Oosterhoff dichotomy," according to the properties of their RR Lyrae stars. Here, we find that most of the lowest metallicity ([Fe/H] < -2.0) clusters, which are essential to an understanding of this phenomenon, display a planar alignment in the outer halo. This alignment, combined with evidence from kinematics and stellar population, indicates a captured origin from a satellite galaxy. We show that, together with the horizontal-branch evolutionary effect, the factor producing the dichotomy could be a small time gap between the cluster-formation epochs in the Milky Way and the satellite. The results oppose the traditional view that the metal-poorest clusters represent the indigenous and oldest population of the Galaxy.
AB - One of the long-standing problems in modern astronomy is the curious division of Galactic globular clusters, the "Oosterhoff dichotomy," according to the properties of their RR Lyrae stars. Here, we find that most of the lowest metallicity ([Fe/H] < -2.0) clusters, which are essential to an understanding of this phenomenon, display a planar alignment in the outer halo. This alignment, combined with evidence from kinematics and stellar population, indicates a captured origin from a satellite galaxy. We show that, together with the horizontal-branch evolutionary effect, the factor producing the dichotomy could be a small time gap between the cluster-formation epochs in the Milky Way and the satellite. The results oppose the traditional view that the metal-poorest clusters represent the indigenous and oldest population of the Galaxy.
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U2 - 10.1126/science.1073090
DO - 10.1126/science.1073090
M3 - Article
VL - 297
SP - 578
EP - 581
JO - Science
JF - Science
SN - 0036-8075
IS - 5581
ER -