Signature of a Massive Rotating Metal-poor Star Imprinted in the Phoenix Stellar Stream
[1];
[2];
[3];
[4];
[5];
[6];
[7];
[8];
[9];
[10];
[11];
[6];
[12];
[13];
[12];
[14]
- Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) (Australia); Monash University, Melbourne, VIC (Australia)
- Carnegie Institution for Science, Pasadena, CA (United States)
- Texas A & M University, College Station, TX (United States)
- Carnegie Institution for Science, Pasadena, CA (United States); Princeton University, NJ (United States)
- University of Edinburgh, Scotland (United Kingdom); University of Cambridge (United Kingdom); Carnegie Mellon University, Pittsburgh, PA (United States)
- Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) (Australia); Australian National University, Canberra, ACT (Australia)
- Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) (Australia); University of Sydney, NSW (Australia)
- Australian National University, Canberra, ACT (Australia)
- University of Surrey, Guildford (United Kingdom)
- University of Sydney, NSW (Australia)
- Lowell Observatory, Flagstaff, AZ (United States); Macquarie University, NSW (Australia)
- Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) (Australia); University of New South Wales, Sydney, NSW (Australia)
- Carnegie Mellon University, Pittsburgh, PA (United States)
- Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) (Australia); Macquarie University, NSW (Australia)
The Phoenix stellar stream has a low intrinsic dispersion in velocity and metallicity that implies the progenitor was probably a low-mass globular cluster. In this work we use Magellan/Magellan Inamori Kyocera Echelle (MIKE) high-dispersion spectroscopy of eight Phoenix stream red giants to confirm this scenario. In particular, we find negligible intrinsic scatter in metallicity ($$σ$$([FE II/H]) = $${0.04}_{-0.03}^{+0.11}$$) and a large peak-to-peak range in [Na/Fe] and [Al/Fe] abundance ratios, consistent with the light element abundance patterns seen in the most metal-poor globular clusters. However, unlike any other globular cluster, we also find an intrinsic spread in [Sr II/Fe] spanning ~1 dex, while [Ba II/Fe] shows nearly no intrinsic spread ($$σ$$([Ba II/H]) = $${0.03}_{-0.02}^{+0.10}$$). This abundance signature is best interpreted as slow-neutron-capture element production from a massive fast-rotating metal-poor star (15–20 $$M$$⊙, $$v$$ini/$$v$$crit = 0.4, [Fe/H] = -3.8). The low inferred cluster mass suggests the system would have been unable to retain supernovae ejecta, implying that any massive fast-rotating metal-poor star that enriched the interstellar medium must have formed and evolved before the globular cluster formed. Furthermore, neutron-capture element production from asymptotic giant branch stars or magneto-rotational instabilities in core-collapse supernovae provide poor fits to the observations. We also report one Phoenix stream star to be a lithium-rich giant ($$A$$(Li) = 3.1 ± 0.1). At [Fe/H ] = -2.93; it is among the most metal-poor lithium-rich giants known.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA); Heising-Simons Foundation
- Grant/Contract Number:
- AC02-05CH11231; AC02-07CH11359; AC02-05CH1123; AST-0950945; AST-1238877; AST-1714873; AST-1813881; HST-HF2-51439.001; HST-HF2-51393.001; HST-HF2-51441.001; HF2-51439.001; NAS5-26555; 2018-1030; NNX08AR22G
- OSTI ID:
- 1983178
- Journal Information:
- The Astrophysical Journal, Vol. 921, Issue 1; ISSN 0004-637X
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
The Southern Stellar Stream Spectroscopic Survey (S 5): Chemical Abundances of Seven Stellar Streams
The R-process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510