Young pre-Low-Mass X-ray Binaries in propeller phase : Nature of the 6.7-hour periodic X-ray source 1E 161348-5055 in RCW 103

Discovery of the 6.7-hour periodicity in the X-ray source 1E 161348-5055 in RCW 103 has led to investigations of the nature of this periodicity. We explore a model for 1E 161348-5055, wherein a fast-spinning neutron star with a magnetic field $\sim 10^{12}$ G in a young pre-Low-Mass X-ray Binary (pre-LMXB) with an eccentric orbit of period 6.7 hr operates in the “propeller” phase. The 6.7-hr light curve of 1E 161348-5055 can be quantitatively accounted by a model of orbitally-modulated mass transfer through a viscous accretion disk and subsequent propeller emission (both Illarionov-Sunyaev type and Romanova-Lovelace et al type), and spectral and other properties are also in agreement. Formation and evolution of model systems are shown to be in accordance both with standard theories.

💡 Research Summary

The paper addresses the puzzling 6.7‑hour periodic X‑ray modulation observed in the source 1E 161348‑5055 (hereafter 1E 1613) located in the supernova remnant RCW 103. Instead of interpreting the periodicity as a neutron‑star spin or orbital period of a conventional low‑mass X‑ray binary, the authors propose that 1E 1613 is a young pre‑low‑mass X‑ray binary (pre‑LMXB) in which a fast‑spinning neutron star (initial spin period of a few milliseconds) with a magnetic field of order 10¹² G is currently operating in the “propeller” regime. The binary has an eccentric orbit with a period equal to the observed 6.7 h.

In this scenario, mass transfer from the low‑mass companion (≈ 0.8 M⊙) is strongly modulated by the orbital phase. Near periastron the Roche‑lobe overflow through the L₁ point peaks, delivering material at a rate
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