Outburst characteristics of transient low-mass X-ray binary 4U 1608–52

GÜNGÖR C.

Turkish Journal of Physics, vol.50, no.1, pp.59-68, 2026 (ESCI, Scopus, TRDizin) identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 1
  • Publication Date: 2026
  • Doi Number: 10.55730/1300-0101.2801
  • Journal Name: Turkish Journal of Physics
  • Journal Indexes: Emerging Sources Citation Index (ESCI), Scopus, Compendex, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.59-68
  • Keywords: accretion disks, individual (4U 1608–52), Neutron stars, X-ray binaries
  • Istanbul University Affiliated: Yes

Abstract

We present a detailed analysis of the long-term X-ray light curve of 4U 1608–52, focusing on fast-rising exponential-decay (FRED) outbursts, low-intensity states, and quiescent intervals. By calibrating the onset times of the outbursts, we identify three distinct classes for the FRED-type events: (i) the long-high outbursts, exceeding ∼50 d in duration with peak count rates above ∼40 cnt s−1 ; (ii) the short-medium outbursts, with durations of ∼20 d and peak count rates of ∼30–50 cnt s−1 ; and (iii) the short-low outbursts, also lasting ∼20 d but reaching only ∼20–30 cnt s−1 at peak. Furthermore, we examine the relation between preoutburst duration and the peak and integrated count rates of the upcoming outburst. We show that outbursts following longer quiescent periods tend to be more energetic.