Theia 456: Tidally Shredding an Open Cluster

Fuente: arXiv
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Autores principales: Tregoning, Kyle R., Andrews, Jeff J., Agüeros, Marcel A., Cargile, Phillip A., Chanamé, Julio, Curtis, Jason L., Schuler, Simon C.
Formato: Preprint
Publicado: 2024
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author Tregoning, Kyle R.
Andrews, Jeff J.
Agüeros, Marcel A.
Cargile, Phillip A.
Chanamé, Julio
Curtis, Jason L.
Schuler, Simon C.
author_facet Tregoning, Kyle R.
Andrews, Jeff J.
Agüeros, Marcel A.
Cargile, Phillip A.
Chanamé, Julio
Curtis, Jason L.
Schuler, Simon C.
contents The application of clustering algorithms to the Gaia astrometric catalog has revolutionized our census of stellar populations in the Milky Way, including the discovery of many new, dispersed structures. We focus on one such structure, Theia 456 (COIN-Gaia-13), a loosely bound collection of ~320 stars spanning ~120 pc that has previously been shown to exhibit kinematic, chemical, and gyrochronal coherency, indicating a common origin. We obtain follow-up radial velocities and supplement these with Gaia astrometry to perform an in-depth dynamical analysis of Theia 456. By integrating stellar orbits through a Milky Way potential, we find the currently dispersed structure coalesced into a small cluster in the past. Via Bayesian modeling, we derive a kinematic age of 245 +/- 3 Myr (statistical), a half-mass radius of 9 +/- 2 pc, and an initial one-dimensional velocity dispersion of 0.14 +/- 0.02 km/s. Our results are entirely independent of model isochrones, details of stellar evolution, and internal cluster dynamics, and the statistical precision in our age derivation rivals that of the most precise age-dating techniques known today, though our imperfect knowledge of the Milky Way potential and simple spherical model for Theia 456 at birth add additional uncertainties. Using posterior predictive checking, we confirm these results are robust under reasonable variations to the Milky Way potential. Such low density structures that are disrupted by the Galactic tides before virializing may be ubiquitous, signifying that Theia 456 is a valuable benchmark for studying the dynamical history of stellar populations in the Milky Way.
format Preprint
id arxiv_https___arxiv_org_abs_2405_13133
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Theia 456: Tidally Shredding an Open Cluster
Tregoning, Kyle R.
Andrews, Jeff J.
Agüeros, Marcel A.
Cargile, Phillip A.
Chanamé, Julio
Curtis, Jason L.
Schuler, Simon C.
Solar and Stellar Astrophysics
Astrophysics of Galaxies
The application of clustering algorithms to the Gaia astrometric catalog has revolutionized our census of stellar populations in the Milky Way, including the discovery of many new, dispersed structures. We focus on one such structure, Theia 456 (COIN-Gaia-13), a loosely bound collection of ~320 stars spanning ~120 pc that has previously been shown to exhibit kinematic, chemical, and gyrochronal coherency, indicating a common origin. We obtain follow-up radial velocities and supplement these with Gaia astrometry to perform an in-depth dynamical analysis of Theia 456. By integrating stellar orbits through a Milky Way potential, we find the currently dispersed structure coalesced into a small cluster in the past. Via Bayesian modeling, we derive a kinematic age of 245 +/- 3 Myr (statistical), a half-mass radius of 9 +/- 2 pc, and an initial one-dimensional velocity dispersion of 0.14 +/- 0.02 km/s. Our results are entirely independent of model isochrones, details of stellar evolution, and internal cluster dynamics, and the statistical precision in our age derivation rivals that of the most precise age-dating techniques known today, though our imperfect knowledge of the Milky Way potential and simple spherical model for Theia 456 at birth add additional uncertainties. Using posterior predictive checking, we confirm these results are robust under reasonable variations to the Milky Way potential. Such low density structures that are disrupted by the Galactic tides before virializing may be ubiquitous, signifying that Theia 456 is a valuable benchmark for studying the dynamical history of stellar populations in the Milky Way.
title Theia 456: Tidally Shredding an Open Cluster
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2405.13133