Discovery of a compact hierarchical triple main-sequence star system while searching for binary stars with compact objects

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Tanikawa, Ataru, Tajitsu, Akito, Honda, Satoshi, Maehara, Hiroyuki, Sato, Bun'ei, Masuda, Kento, Omiya, Masashi, Izumiura, Hideyuki
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913056171229184
author Tanikawa, Ataru
Tajitsu, Akito
Honda, Satoshi
Maehara, Hiroyuki
Sato, Bun'ei
Masuda, Kento
Omiya, Masashi
Izumiura, Hideyuki
author_facet Tanikawa, Ataru
Tajitsu, Akito
Honda, Satoshi
Maehara, Hiroyuki
Sato, Bun'ei
Masuda, Kento
Omiya, Masashi
Izumiura, Hideyuki
contents We have discovered a compact hierarchical triple main-sequence star system, which is cataloged as Gaia DR3 1010268155897156864 or TIC 21502513. Hereafter, we call it ``G1010''. G1010 consists of a primary (the most massive) star and inner binary that orbit each other. The primary star is a $0.85_{-0.03}^{+0.03}\;{\rm M}_\odot$ main-sequence (MS) star, and the inner binary components are $0.63_{-0.02}^{+0.02}$ and $0.61_{-0.02}^{+0.02}\;{\rm M}_\odot$ MS stars. The outer and inner orbital periods are $277.2_{-1.3}^{+1.6}$ and $\sim 18.26$ days, respectively. G1010 is categorized as a single-lined spectroscopic binary, and its orbital solution indicates that G1010 possibly accompanies a massive compact object, such as a neutron star or massive white dwarf. In order to confirm the presence of a massive compact object, we have performed several-times low signal-to-ratio (SNR) and one-time high SNR spectroscopic observations, and determined the outer orbital parameters. Moreover, we have deeply analyzed the high SNR spectroscopic data, and found that G1010 accompanies not a massive compact object, but an inner binary. We have investigated G1010's light curve in Transiting Exoplanet Survey Satellite (TESS), and concluded that the inner binary is actually an eclipsing binary, not included in TESS Eclipsing Binary Stars. We have obtained the inner orbital parameters from the TESS light curve. G1010 is similar to compact hierarchical triple star systems previously discovered by eclipse timing variation analysis. Our discovery has shown that such triple star systems can be discovered by combination of low- and high-SNR spectroscopic observations with the help of Gaia DR3 and the upcoming Gaia DR4/DR5.
format Preprint
id arxiv_https___arxiv_org_abs_2601_21125
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Discovery of a compact hierarchical triple main-sequence star system while searching for binary stars with compact objects
Tanikawa, Ataru
Tajitsu, Akito
Honda, Satoshi
Maehara, Hiroyuki
Sato, Bun'ei
Masuda, Kento
Omiya, Masashi
Izumiura, Hideyuki
Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
We have discovered a compact hierarchical triple main-sequence star system, which is cataloged as Gaia DR3 1010268155897156864 or TIC 21502513. Hereafter, we call it ``G1010''. G1010 consists of a primary (the most massive) star and inner binary that orbit each other. The primary star is a $0.85_{-0.03}^{+0.03}\;{\rm M}_\odot$ main-sequence (MS) star, and the inner binary components are $0.63_{-0.02}^{+0.02}$ and $0.61_{-0.02}^{+0.02}\;{\rm M}_\odot$ MS stars. The outer and inner orbital periods are $277.2_{-1.3}^{+1.6}$ and $\sim 18.26$ days, respectively. G1010 is categorized as a single-lined spectroscopic binary, and its orbital solution indicates that G1010 possibly accompanies a massive compact object, such as a neutron star or massive white dwarf. In order to confirm the presence of a massive compact object, we have performed several-times low signal-to-ratio (SNR) and one-time high SNR spectroscopic observations, and determined the outer orbital parameters. Moreover, we have deeply analyzed the high SNR spectroscopic data, and found that G1010 accompanies not a massive compact object, but an inner binary. We have investigated G1010's light curve in Transiting Exoplanet Survey Satellite (TESS), and concluded that the inner binary is actually an eclipsing binary, not included in TESS Eclipsing Binary Stars. We have obtained the inner orbital parameters from the TESS light curve. G1010 is similar to compact hierarchical triple star systems previously discovered by eclipse timing variation analysis. Our discovery has shown that such triple star systems can be discovered by combination of low- and high-SNR spectroscopic observations with the help of Gaia DR3 and the upcoming Gaia DR4/DR5.
title Discovery of a compact hierarchical triple main-sequence star system while searching for binary stars with compact objects
topic Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2601.21125