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arXiv · 2111.12098

TIC 5724661: A Long-Period Binary with a Pulsating sdB Star and $δ$ Scuti Variable

Rahul Jayaraman·Saul Rappaport·Lorne Nelson·Donald W. Kurtz·George Dufresne·Gerald Handler·Abdel Senhadji·David W. Latham·George Zhou·Allyson Bieryla·George Ricker
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Abstract

Using TESS 20-sec cadence data, we have discovered an unusual combination of pulsating stars in what we infer to be a binary system. The binary consists of a standard $δ$ Scuti star with pulsations over the range 32-41 d$^{-1}$; this is in a likely wide orbit with a hot subdwarf B (sdB) star, which itself has a large-amplitude p-mode pulsation at 524 d$^{-1}$. We establish constraints on the period of the putative binary by using radial velocity measurements of the $δ$~Scuti star and show that any sdB companion star must orbit with a period greater than a few tens of days. Our identification of this sdB binary serves as an important addition to the relatively small number of sdB binaries known to have orbital periods longer than a few days. We model such a binary using {\tt MESA} and find that this system could be formed through stable, nonconservative mass transfer from either a low- or intermediate-mass progenitor, without undergoing a common envelope phase.

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Rahul Jayaraman, Saul Rappaport, Lorne Nelson, Donald W. Kurtz, George Dufresne, Gerald Handler, Abdel Senhadji, David W. Latham, George Zhou, Allyson Bieryla, George Ricker. 2022-08-02. TIC 5724661: A Long-Period Binary with a Pulsating sdB Star and $δ$ Scuti Variable. https://doi.org/10.3847/1538-4357%2Fac84d0

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