Achromatic late-time variability in thermonuclear X-ray bursts An accretion disk disrupted by a nova-like shell?

作者：in't Zand J J M^*; Galloway D K; Ballantyne D R

来源：Astronomy & Astrophysics, 2011, 525: A111.

DOI：10.1051/0004-6361/201015556

• accretion, accretion disks
• X-rays: binaries
• X-rays: bursts
• X-rays: individuals: 2S 0918-549

An unusual Eddington-limited thermonuclear X-ray burst was detected from the accreting neutron star in 2S 0918-549 with the Rossi X-ray Timing Explorer. The burst commenced with a brief (40 ms) precursor and maintained near-Eddington fluxes during the initial 77 s. These characteristics are indicative of a nova-like expulsion of a shell from the neutron star surface. Starting 122 s into the burst, the burst shows strong (87 +/- 1% peak-to-peak amplitude) achromatic fluctuations for 60 s. We speculate that the fluctuations are caused by Thompson scattering by fully-ionized inhomogeneities in a resettling accretion disk that was disrupted by the effects of super-Eddington fluxes. An expanding shell may be the necessary prerequisite for the fluctuations.

• 出版日期2011-1