A 2.4-12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence

L. Koch-Miramond, P. Ábrahám, Y. Fuchs, J. M. Bonnet-Bidaud, A. Claret

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 μm continuum radiation observed with ISOPHOT-S can be explained by thermal free-free emission in an expanding wind with, above 6.5 μm, a possible additional black-body component with temperature T ∼ 250 K and radius R ∼ 5000 R at 10 kpc, likely due to thermal emission by circumstellar dust. The observed brightness and continuum spectrum closely match that of the Wolf-Rayet star WR 147, a WN8+B0.5 binary system, when rescaled at the same 10 kpc distance as Cygnus X-3. A rough mass loss estimate assuming a WN wind gives ∼1.2 × 10-4 Myr-1. A line at ∼4.3 μm with a more than 4.3 σ detection level, and with a dereddened flux of 126 mJy, is interpreted as the expected He I 3p-3s line at 4.295 μm, a prominent line in the WR 147 spectrum. These results are consistent with a Wolf-Rayet-like companion to the compact object in Cyg X-3 of WN8 type, a later type than suggested by earlier works.

Original languageEnglish
Pages (from-to)877-884
Number of pages8
JournalAstronomy and Astrophysics
Volume396
Issue number3
Publication statusPublished - Dec 2002

Fingerprint

continuums
Wolf-Rayet stars
wolves
thermal emission
brightness
dust
orbitals
radii
radiation
estimates
x rays
temperature
loss
detection

Keywords

  • Infrared: stars
  • Stars: binaries: close
  • Stars: individual: Cyg X-3
  • Stars: mass-loss
  • Stars: Wolf-Rayet

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Koch-Miramond, L., Ábrahám, P., Fuchs, Y., Bonnet-Bidaud, J. M., & Claret, A. (2002). A 2.4-12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence. Astronomy and Astrophysics, 396(3), 877-884.

A 2.4-12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence. / Koch-Miramond, L.; Ábrahám, P.; Fuchs, Y.; Bonnet-Bidaud, J. M.; Claret, A.

In: Astronomy and Astrophysics, Vol. 396, No. 3, 12.2002, p. 877-884.

Research output: Contribution to journalArticle

Koch-Miramond, L, Ábrahám, P, Fuchs, Y, Bonnet-Bidaud, JM & Claret, A 2002, 'A 2.4-12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence', Astronomy and Astrophysics, vol. 396, no. 3, pp. 877-884.
Koch-Miramond L, Ábrahám P, Fuchs Y, Bonnet-Bidaud JM, Claret A. A 2.4-12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence. Astronomy and Astrophysics. 2002 Dec;396(3):877-884.
Koch-Miramond, L. ; Ábrahám, P. ; Fuchs, Y. ; Bonnet-Bidaud, J. M. ; Claret, A. / A 2.4-12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence. In: Astronomy and Astrophysics. 2002 ; Vol. 396, No. 3. pp. 877-884.
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