A Caltech Library Service

Constraints on the binary black hole hypothesis for system LB-1

Shen, Rong-Feng and Matzner, Christopher D. and Howard, Andrew W. and Zhang, Wei (2019) Constraints on the binary black hole hypothesis for system LB-1. . (Unpublished)

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


At about 70 solar masses, the recently-discovered dark object orbited by a B-type star in the system LB-1 is difficult to understand as the end point of standard stellar evolution, except as a binary black hole (BBH). LB-1 shows a strong, broad H-alpha emission line that is best attributed to a gaseous disk surrounding the dark mass. We use the observed H-alpha line shape, particularly its wing extension, to constrain the inner radius of the disk and thereby the separation of a putative BBH. The hypothesis of a current BBH is effectively ruled out on the grounds that its merger time must be a small fraction of the current age of the B star. The hypothesis of a previous BBH that merged to create the current dark mass is also effectively ruled out by the low orbital eccentricity, due to the combination of mass loss and kick resulted from gravitational wave emission in any past merger. We conclude that the current dark mass is a single black hole produced by the highly mass-conserving, monolithic collapse of a massive star.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Howard, Andrew W.0000-0001-8638-0320
Additional Information:RFS thanks the hospitality of Canadian Institute of Theoretical Astrophysics where part of this work was carried out.
Group:Astronomy Department
Subject Keywords:stellar mass black holes – H I line emission – stellar accretion disks – late stellar evolution – gravitational wave sources
Record Number:CaltechAUTHORS:20200420-103804380
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102649
Deposited By: Tony Diaz
Deposited On:20 Apr 2020 19:10
Last Modified:20 Apr 2020 19:10

Repository Staff Only: item control page