Analysis of Two Eclipsing Hot Subdwarf Binaries with a Low Mass Stellar and a Brown Dwarf Companion

TL;DR

This paper reports the discovery and analysis of two eclipsing hot subdwarf B binary systems, one with a brown dwarf companion and the other with a low-mass stellar companion, providing insights into their formation.

Contribution

It presents the first detailed characterization of two eclipsing sdB binaries with substellar and low-mass stellar companions, enhancing understanding of their formation channels.

Findings

Identified two new eclipsing sdB binaries with substellar and low-mass stellar companions.

Constrained the system parameters through combined spectroscopic and light curve analysis.

Supported the common envelope ejection as a formation mechanism for these systems.

Abstract

The formation of hot subdwarf stars (sdBs), which are core helium-burning stars located on the extended horizontal branch, is still not understood. Many of the known hot subdwarf stars reside in close binary systems with short orbital periods between a few hours and a few days with either M star or white dwarf companions. Common envelope ejection is the most probable formation channel. Among these, eclipsing systems are of special importance because it is possible to constrain the parameters of both components tightly by combining spectroscopic and light curve analyses. We report the discovery of two eclipsing binaries with a brown dwarf (< 0.07 M*) and a 0.15 M* late main sequence star companion in close orbits around sdB stars.