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Title: Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters

Abstract

In this Letter, we propose a formation channel for low-mass X-ray binaries with black hole accretors and non-degenerate donors via grazing tidal encounters with subgiants. We estimate that in a typically dense globular cluster with a core density of 10{sup 5} stars pc{sup −3}, the formation rates are about one binary per Gyr per 50–100 retained black holes. The donors—stripped subgiants—will be strongly underluminous when compared to subgiant or giant branch stars of the same colors. The products of tidal stripping are underluminous by at least one magnitude for several hundred million years when compared to normal stars of the same color, and differ from underluminous red stars that could be produced by non-catastrophic mass transfer in an ordinary binary. The dynamically formed binaries become quiescent LMXBs, with lifetimes of about a Gyr. The expected number of X-ray binaries is one per 50–200 retained black holes, while the expected number of strongly underluminous subsubgiant is about half this. The presence of strongly underluminous stars in a GC may be indicative of the presence of black holes.

Authors:
; ; ;  [1]
  1. Department of Physics, University of Alberta, Edmonton, AB T6G 2E7 (Canada)
Publication Date:
OSTI Identifier:
22654439
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 843; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY ALLOY SYSTEMS; BLACK HOLES; COMPARATIVE EVALUATIONS; DENSITY; HYDRODYNAMICS; LIFETIME; MASS TRANSFER; STARS; STRIPPING; X RADIATION

Citation Formats

Ivanova, Natalia, Rocha, Cassio A. da, Van, Kenny X., and Nandez, Jose L. A., E-mail: nata.ivanova@ualberta.ca. Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA7B76.
Ivanova, Natalia, Rocha, Cassio A. da, Van, Kenny X., & Nandez, Jose L. A., E-mail: nata.ivanova@ualberta.ca. Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters. United States. doi:10.3847/2041-8213/AA7B76.
Ivanova, Natalia, Rocha, Cassio A. da, Van, Kenny X., and Nandez, Jose L. A., E-mail: nata.ivanova@ualberta.ca. Mon . "Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters". United States. doi:10.3847/2041-8213/AA7B76.
@article{osti_22654439,
title = {Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters},
author = {Ivanova, Natalia and Rocha, Cassio A. da and Van, Kenny X. and Nandez, Jose L. A., E-mail: nata.ivanova@ualberta.ca},
abstractNote = {In this Letter, we propose a formation channel for low-mass X-ray binaries with black hole accretors and non-degenerate donors via grazing tidal encounters with subgiants. We estimate that in a typically dense globular cluster with a core density of 10{sup 5} stars pc{sup −3}, the formation rates are about one binary per Gyr per 50–100 retained black holes. The donors—stripped subgiants—will be strongly underluminous when compared to subgiant or giant branch stars of the same colors. The products of tidal stripping are underluminous by at least one magnitude for several hundred million years when compared to normal stars of the same color, and differ from underluminous red stars that could be produced by non-catastrophic mass transfer in an ordinary binary. The dynamically formed binaries become quiescent LMXBs, with lifetimes of about a Gyr. The expected number of X-ray binaries is one per 50–200 retained black holes, while the expected number of strongly underluminous subsubgiant is about half this. The presence of strongly underluminous stars in a GC may be indicative of the presence of black holes.},
doi = {10.3847/2041-8213/AA7B76},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 843,
place = {United States},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}