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Paper: Resolved, but Unresolved: A Trio of Triple– and Quadruple–Star Hot Subdwarf Systems
Volume: 481, 6th Meeting on Hot Subdwarf Stars and Related Objects
Page: 301
Authors: Barlow, B.; Wade, R.; Liss, S.; Stark, M.
Abstract: As part of a survey with the Hobby-Eberly Telescope (see Wade et al., these proceedings), we have been monitoring the radial velocities of 15 hot subdwarf systems with main sequence companions, with the goal of measuring their binary orbital periods. Three of our targets are known to be resolved visual pairs with separations ranging from 0.2″ to 2″. Velocity measurements of these systems reveal orbital periods that are incompatible with their angular separations on the sky; thus, they are likely multiple-component star systems with inner sdB binaries. Two of these inner binaries have long periods (P ∼ 930 d), while the other has a short period (P < 10 d). Interestingly, one of the long–period binaries shows a significant eccentricity of e = 0.54, challenging the conventional Roche Lobe overflow formation channel for hot subdwarfs. Here we discuss the nature of these systems and present up-to-date measurements of their orbital parameters.
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