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Discovery of astrometric accelerations by dark companions in the globular cluster ω Centauri

Platais, I, Sahlmann, J, Girardi, L, Kozhurina-Platais, V, Kamann, S, Pourbaix, D, Wragg, F, Lemson, G and Mitschang, A (2024) Discovery of astrometric accelerations by dark companions in the globular cluster ω Centauri. The Astrophysical Journal, 963 (1). ISSN 0004-637X

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We present results from the search for astrometric accelerations of stars in ω Centauri using 13 years of regularly-scheduled Hubble Space Telescope WFC3/UVIS calibration observations in the cluster core. The high-precision astrometry of∼160000 sources was searched for significant deviations from linear proper motion. This led to the discovery of four cluster members and one foreground field star with compelling acceleration patterns. We interpret them as the result of the gravitational pull by an invisible companion and determined preliminary Keplerian orbit parameters, including the companion’s mass. For the cluster members our analysis suggests periods ranging from 8.8 to 19+ years and dark companions in the mass range of ∼0.7to∼1.4M⊙. At least one companion could exceed the upper mass-boundary of white dwarfs and can be classified as a neutron-star candidate.

Item Type: Article
Uncontrolled Keywords: astro-ph.SR; astro-ph.SR; astro-ph.GA
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: American Astronomical Society
Related URLs:
SWORD Depositor: A Symplectic
Date Deposited: 28 Feb 2024 17:02
Last Modified: 28 Feb 2024 17:02
DOI or ID number: 10.3847/1538-4357/ad167c
URI: https://researchonline.ljmu.ac.uk/id/eprint/22193
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