An X-ray and optical light curve model of the eclipsing symbiotic binary SMC3

Mariko Kato, Izumi Hachisu, Joanna Mikołajewska

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Some binary evolution scenarios for Type Ia supernovae (SNe Ia) include long-period binaries that evolve to symbiotic supersoft X-ray sources in their late stage of evolution. However, symbiotic stars with steady hydrogen burning on the white dwarf's (WD) surface are very rare, and the X-ray characteristics are not well known. SMC3 is one such rare example and a key object for understanding the evolution of symbiotic stars to SNe Ia. SMC3 is an eclipsing symbiotic binary, consisting of a massive WD and red giant (RG), with an orbital period of 4.5 years in the Small Magellanic Cloud. The long-term V light curve variations are reproduced as orbital variations in the irradiated RG, whose atmosphere fills its Roche lobe, thus supporting the idea that the RG supplies matter to the WD at rates high enough to maintain steady hydrogen burning on the WD. We also present an eclipse model in which an X-ray-emitting region around the WD is almost totally occulted by the RG swelling over the Roche lobe on the trailing side, although it is always partly obscured by a long spiral tail of neutral hydrogen surrounding the binary in the orbital plane.

Original languageEnglish
Article number5
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2013 Jan 20
Externally publishedYes


  • binaries: eclipsing
  • binaries: symbiotic
  • circumstellar matter
  • stars: individual (SMC3)
  • stars: winds, outflows
  • white dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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