Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution

Intergalactic wandering stars (IWSs) within 10 Mpc remain a poorly explored area of astronomy. Such stars, if they exist, are supposed to be wandering objects as they are not bound by the gravitational potential of any galaxy. We set out to conduct dedicated studies to unravel such a wandering stell...

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Main Authors: Jia-Hui Wang, Maosheng Xiang, Ji-Feng Liu
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adf8c8
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author Jia-Hui Wang
Maosheng Xiang
Ji-Feng Liu
author_facet Jia-Hui Wang
Maosheng Xiang
Ji-Feng Liu
author_sort Jia-Hui Wang
collection DOAJ
description Intergalactic wandering stars (IWSs) within 10 Mpc remain a poorly explored area of astronomy. Such stars, if they exist, are supposed to be wandering objects as they are not bound by the gravitational potential of any galaxy. We set out to conduct dedicated studies to unravel such a wandering stellar population. As the first paper of the series, in the present work, we model the distance distribution and luminosity function of IWSs formed via the Hills mechanism of the Galactic central massive black hole (GCMBH). We implement a numerical simulation to generate IWSs, taking the ejection history of the GCMBH and the stellar evolution process into consideration, and present their luminosity function in the distance range of 200 kpc–10 Mpc. Our results suggest that a few hundred thousand IWSs have been generated by the GCMBH via the Hills mechanism in the past 14 billion yr. These IWSs have an apparent magnitude peaking at 30–35 mag in the Sloan Digital Sky Survey r band, which are hard to detect. However, a few thousand of them at the bright end are detectable by upcoming wide-field deep surveys, such as the China Space Station Telescope and the Vera Rubin Observatory. The forthcoming discovery of such a wandering stellar population will open the door for a precise understanding of the matter constitution of the nearby intergalactic space and the dynamical history of galaxies in the local Universe.
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spelling doaj-art-005b461796b84d0dbb67db0c84f7cf342025-08-25T05:51:08ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0199015810.3847/1538-4357/adf8c8Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity DistributionJia-Hui Wang0https://orcid.org/0009-0009-3372-5271Maosheng Xiang1https://orcid.org/0000-0002-5818-8769Ji-Feng Liu2https://orcid.org/0000-0002-2874-2706National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100012, People’s Republic of China ; wangjh@bao.ac.cn, msxiang@nao.cas.cn, jfliu@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100012, People’s Republic of China ; wangjh@bao.ac.cn, msxiang@nao.cas.cn, jfliu@nao.cas.cn; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100012, People’s Republic of China ; wangjh@bao.ac.cn, msxiang@nao.cas.cn, jfliu@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of China; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaIntergalactic wandering stars (IWSs) within 10 Mpc remain a poorly explored area of astronomy. Such stars, if they exist, are supposed to be wandering objects as they are not bound by the gravitational potential of any galaxy. We set out to conduct dedicated studies to unravel such a wandering stellar population. As the first paper of the series, in the present work, we model the distance distribution and luminosity function of IWSs formed via the Hills mechanism of the Galactic central massive black hole (GCMBH). We implement a numerical simulation to generate IWSs, taking the ejection history of the GCMBH and the stellar evolution process into consideration, and present their luminosity function in the distance range of 200 kpc–10 Mpc. Our results suggest that a few hundred thousand IWSs have been generated by the GCMBH via the Hills mechanism in the past 14 billion yr. These IWSs have an apparent magnitude peaking at 30–35 mag in the Sloan Digital Sky Survey r band, which are hard to detect. However, a few thousand of them at the bright end are detectable by upcoming wide-field deep surveys, such as the China Space Station Telescope and the Vera Rubin Observatory. The forthcoming discovery of such a wandering stellar population will open the door for a precise understanding of the matter constitution of the nearby intergalactic space and the dynamical history of galaxies in the local Universe.https://doi.org/10.3847/1538-4357/adf8c8Hypervelocity starsMilky Way GalaxyMilky Way Galaxy physicsLocal Group
spellingShingle Jia-Hui Wang
Maosheng Xiang
Ji-Feng Liu
Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution
The Astrophysical Journal
Hypervelocity stars
Milky Way Galaxy
Milky Way Galaxy physics
Local Group
title Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution
title_full Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution
title_fullStr Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution
title_full_unstemmed Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution
title_short Intergalactic Wandering Stars in the Local Universe: Theoretical Predictions for Their Distance and Luminosity Distribution
title_sort intergalactic wandering stars in the local universe theoretical predictions for their distance and luminosity distribution
topic Hypervelocity stars
Milky Way Galaxy
Milky Way Galaxy physics
Local Group
url https://doi.org/10.3847/1538-4357/adf8c8
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AT jifengliu intergalacticwanderingstarsinthelocaluniversetheoreticalpredictionsfortheirdistanceandluminositydistribution