The Spectrum of SS 433 in the H and K Bands
- Department of Astronomy, University of Texas at Austin, C1400, Austin, TX 78712 (United States)
- Korea Astronomy and Space Science Institute, 776 Daeduk-daero, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)
SS 433 is an X-ray binary and the source of sub-relativistic, precessing, baryonic jets. We present high-resolution spectrograms of SS 433 in the infrared H and K bands. The spectrum is dominated by hydrogen and helium emission lines. The precession phase of the emission lines from the jet continues to be described by a constant period, P{sub jet}=162.375 days. The limit on any secularly changing period is | P-dot |≲10{sup −5}. The He i λ2.0587 μm line has complex and variable P-Cygni absorption features produced by an inhomogeneous wind with a maximum outflow velocity near 900 km s{sup −1}. The He ii emission lines in the spectrum also arise in this wind. The higher members of the hydrogen Brackett lines show a double-peaked profile with symmetric wings extending more than ±1500 km s{sup −1} from the line center. The lines display radial velocity variations in phase with the radial velocity variation expected of the compact star, and they show a distortion during disk eclipse that we interpret as a rotational distortion. We fit the line profiles with a model in which the emission comes from the surface of a symmetric, Keplerian accretion disk around the compact object. The outer edge of the disk has velocities that vary from 110 to 190 km s{sup −1}. These comparatively low velocities place an important constraint on the mass of the compact star: its mass must be less than 2.2 M{sub ⊙} and is probably less than 1.6 M{sub ⊙}.
- OSTI ID:
- 22872675
- Journal Information:
- Astrophysical Journal, Vol. 841, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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