X-ray binaries (XRBs) are systems where material is being accreted onto a compact object (white dwarf/neutron star/stellar-mass black hole) from a donor star, and as such they provide an excellent laboratory for studies of accretion physics. While the physics of the donor–recipient pair is well characterized, little is known about the wider system, including whether such systems have circumbinary disks or companions (planets, brown dwarfs or stars). Myriam Prasow-Émond and colleagues have used the adaptive optics of Keck and the vortex coronagraph of the NIRC2 instrument to study the ~100–10,000 au regions around 13 high-mass XRBs, finding several candidate circumbinary companions using high-contrast imaging.

L′-band near-infrared images of the targeted XRBs were examined for potential companions, with four of the images not containing any. One system for which there were two observing epochs, γ Cas, was subjected to a proper-motion study, revealing a companion at 380 au projected separation. For the remaining binaries, a 3D model of the star fields within the Galaxy (TRILEGAL) was used to determine whether candidates might be gravitationally bound to the target XRBs or foreground/background contamination. Eight systems in total were found to host candidate circumbinary companions, giving a frequency of multiple systems (MF) of ~0.6 and a companion frequency (CF) of ~0.8 additional sources per XRB. However, all candidates will need to be confirmed with follow-up proper-motion analyses.

X射线双星（XRB）是物质从供体恒星吸积到致密天体（白矮星/中子星/恒星质量黑洞）上的系统，因此它们为吸积物理研究提供了一个极好的实验室。虽然供体-受体对的物理特征已得到很好的表征，但人们对更广泛的系统知之甚少，包括此类系统是否有环绕双星盘或伴星（行星、棕矮星或恒星）。 Myriam Prasow-Émond 及其同事使用 Keck 的自适应光学器件和 NIRC2 仪器的涡旋日冕仪来研究 13 个高质量 XRB 周围的约 100-10,000 个 au 区域，并使用高对比度成像找到了几个候选的环双星伴星。

检查了目标 XRB 的 L' 波段近红外图像中是否有潜在的伴星，其中四张图像不包含任何伴星。对一个有两个观测历元的系统 γ Cas 进行了自行研究，发现了一个预计距离为 380 天文单位的伴星。对于其余的双星，使用银河系内星场的 3D 模型 (TRILEGAL) 来确定候选双星是否可能通过重力束缚到目标 XRB 或前景/背景污染。总共有 8 个系统被发现拥有候选的环绕双星伴星，每个 XRB 的多系统频率 (MF) 约为 0.6，伴星频率 (CF) 约为 0.8 个附加源。然而，所有候选者都需要通过后续的适当运动分析来确认。