The small boxy/peanut structure of the Milky Way traced by old stars
We analyse the positions of RR Lyrae stars in the central region of the Milky Way. In addition to the overall bar shape detected previously, we find evidence for a peanut shaped structure, in form of overdensities near ℓ = −2 and 1° at b ∼ −3.5°. The corresponding physical distance between the two p...
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| Main Authors: | , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2022
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| In: |
Monthly notices of the Royal Astronomical Society
Year: 2022, Volume: 509, Issue: 3, Pages: 4532-4537 |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stab3294 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1093/mnras/stab3294
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| Author Notes: | Marcin Semczuk, Walter Dehnen, Ralph Schönrich and E. Athanassoula |
| Summary: | We analyse the positions of RR Lyrae stars in the central region of the Milky Way. In addition to the overall bar shape detected previously, we find evidence for a peanut shaped structure, in form of overdensities near ℓ = −2 and 1° at b ∼ −3.5°. The corresponding physical distance between the two peaks of the peanut is $\sim 0.7\,$ kpc, significantly shorter than that found from near-IR images (3.3 kpc) and red-clump stars. Qualitatively this is expected from ‘fractionation’ of bar orbits, which we demonstrate to be matched in a simulation of an inside-out growing disc subsequently forming a bar. |
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| Item Description: | Advance access publication 2021 November 13 Gesehen am 23.03.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stab3294 |