J/A+A/699/A291 Omega Centauri with phylogenetics (Jofre+, 2025)
Studying stellar populations in Omega Centauri with phylogenetic.
Jofre P., Aguilera-Gomez C., Villarreal P., Cubillos F.A., Das P., Hua X.,
Yates R., Silva P., Vitali S., Pena T., Signor T., Walsen K., Tissera P.,
Rojas-Arriagada A., Johnston E., Gilmore G., Foley R.
<Astron. Astrophys. 699, A291 (2025)>
=2025A&A...699A.291J 2025A&A...699A.291J (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar ; Abundances
Keywords: Stellar populations, phylogenetics
Abstract:
The nature and formation history of our Galaxy's largest and most
enigmatic stellar cluster, known as Omega Centauri (omega Cen)
remains debated.
Here, we offer a novel approach to disentangling the complex stellar
populations within omega Cen based on phylogenetics methodologies from
evolutionary biology. These include the Gaussian Mixture Model and
Neighbor-Joining clustering algorithms applied to a set of chemical
abundances of omega Cen stellar members.
Instead of using the classical approach in astronomy of grouping them
into separate populations, we focused on how the stars are related to
each other. We could identify stars that likely formed in globular
clusters versus those originating from prolonged in-situ star
formation and how these stars interconnect. Our analysis supports the
hypothesis that omega Cen might be a nuclear star cluster of a galaxy
accreted by the Milky Way with a mass of about 109M☉.
Furthermore, we revealed the existence of a previously unidentified
in-situ stellar population with a distinct chemical pattern unlike any
known population found in the Milky Way to date.
Our analysis of omega Cen is an example of the success of
cross-disciplinary research and shows the vast potential of applying
evolutionary biology tools to astronomical datasets, opening new
avenues for understanding the chemical evolution of complex stellar
systems.
Description:
In this work we use two published datasets of stars from omega Cen,
both containing data of chemical abundances obtained from high
resolution spectral analysis.
For Optical Data, abundances come from Johnsom et al.,
2010ApJ...722.1373J 2010ApJ...722.1373J, Cat. J/ApJ/722/1373.
For Infrared Data, abundances come from Meszaros et al.,
2021MNRAS.505.1645M 2021MNRAS.505.1645M.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
optical.dat 120 122 Optical Data from Johnsom et al.,
2010ApJ...722.1373J 2010ApJ...722.1373J, Cat. J/ApJ/722/1373
infrared.dat 116 137 Infrared data from Meszaros et al.,
2021MNRAS.505.1645M 2021MNRAS.505.1645M
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See also:
J/ApJ/722/1373 : ω Centauri giants abundances (Johnson+, 2010)
Byte-by-byte Description of file: optical.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- StarID StarID used in the paper (SOP_NNN)
9- 13 I5 --- LEID LEID identification number
15- 33 I19 --- GaiaDR3 ? GaiaDR3 source_id
36- 53 F18.15 mag Gmag ? Apparent G magnitude taken from Gaia DR3
55- 59 F5.2 --- [Fe/H] Metallicity [Fe/H]
61- 65 F5.2 --- [O/Fe] Abundance ratio of [O/Fe]
67- 71 F5.2 --- [Na/Fe] Abundance ratio of [Na/Fe]
73- 77 F5.2 --- [Al/Fe] Abundance ratio of [Al/Fe]
79- 83 F5.2 --- [Si/Fe] Abundance ratio of [Si/Fe]
85- 88 F4.2 --- [Ca/Fe] Abundance ratio of [Ca/Fe]
90- 94 F5.2 --- [Sc/Fe] Abundance ratio of [Sc/Fe]
96-100 F5.2 --- [Ti/Fe] Abundance ratio of [Ti/Fe]
102-106 F5.2 --- [Ni/Fe] Abundance ratio of [Ni/Fe]
108-112 F5.2 --- [La/Fe] Abundance ratio of [La/Fe]
114-118 F5.2 --- [Eu/Fe] Abundance ratio of [Eu/Fe]
120 I1 --- gmm3 [1/3] Group assigned with the
Gaussian Mixture Model
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Byte-by-byte Description of file: infrared.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- StarID StarID used in the paper (SIR_NNN)
9- 26 A18 --- APOGEE APOGEE identifier (2MHHMMSSss+DDMMSSs)
28- 46 I19 --- GaiaDR3 ? Gaia DR3 source_id
49- 66 F18.15 mag Gmag ? Apparent G magnitude taken from Gaia DR3
68- 73 F6.3 --- [Fe/H] Metallicity [Fe/H]
75- 80 F6.3 --- [O/Fe] Abundance ratio of [O/Fe]
82- 87 F6.3 --- [Mg/Fe] Abundance ratio of [Mg/Fe]
89- 94 F6.3 --- [Al/Fe] Abundance ratio of [Al/Fe]
96-100 F5.3 --- [Si/Fe] Abundance ratio of [Si/Fe]
102-107 F6.3 --- [Ca/Fe] Abundance ratio of [Ca/Fe]
109-114 F6.3 --- [Ce/Fe] Abundance ratio of [Ce/Fe]
116 I1 --- gmm3 [1/4] Group assigned with the
Gaussian Mixture Model
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Acknowledgements:
Paula Jofre, paula.jofre(at)mail.udp.cl
References:
Johnsom et al., 2010ApJ...722.1373J 2010ApJ...722.1373J, Cat. J/ApJ/722/1373
Meszaros et al., 2021MNRAS.505.1645M 2021MNRAS.505.1645M
(End) Patricia Vannier [CDS] 10-Jun-2025