Multi-frequency variations of the Wolf-Rayet system HD193793 (WC7pd+O4-5) - III. - IUE observations
| العنوان: | Multi-frequency variations of the Wolf-Rayet system HD193793 (WC7pd+O4-5) - III. - IUE observations |
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| المؤلفون: | D.Y.A. Setia Gunawan, W. Wamsteker, H.F. Henrichs, Lex Kaper, Peredur M. Williams, D. J. Stickland, K. A. van der Hucht |
| المساهمون: | Low Energy Astrophysics (API, FNWI), Kapteyn Astronomical Institute |
| المصدر: | Astronomy & Astrophysics, 376, 460-477. EDP Sciences Astronomy & astrophysics, 376(2), 460-475. EDP Sciences |
| سنة النشر: | 2001 |
| مصطلحات موضوعية: | media_common.quotation_subject, stars : winds, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, stars : Wolf-Rayet, stars : individual : WR140, LINE-PROFILE VARIATIONS, Spectral line, outflows, Wolf–Rayet star, TERMINAL VELOCITIES, Astrophysics::Solar and Stellar Astrophysics, Eccentricity (behavior), ultraviolet : stars, Astrophysics::Galaxy Astrophysics, media_common, Eclipse, O-type star, Line (formation), RIPPLE CORRECTION, Orbital elements, Physics, MULTIFREQUENCY VARIATIONS, Astronomy, Velocity dispersion, Astronomy and Astrophysics, HIGH-RESOLUTION SPECTRA, stars : winds, outflows, Space and Planetary Science, COLLIDING WINDS, RADIO-EMISSION, stars : binaries : spectroscopic, X-RAY, Astrophysics::Earth and Planetary Astrophysics, stars : early-type, WC STARS, HD-193793 |
| الوصف: | The colliding-wind binary system WR140 (HD193793, WC7pd+O4-5, P=7.94 yr) was monitored in the ultraviolet by IUE from 1979 to 1994 in 35 short-wavelength high-resolution spectra. An absorption-line radial-velocity solution is obtained from the photospheric lines of the O component, by comparison with a single O star. The resulting orbital parameters, e=0.87 +/- 0.05, w=31 degrees +/- 9 degrees and Ko star=25 +/- 15 km s(-1), confirm the large eccentricity of the orbit, within the uncertainties of previous optical studies. This brings the weighted mean UV-optical eccentricity to e=0.85 +/- 0.04. Occultation of the O-star light by the WC wind and the WC+O colliding-wind region results into orbital modulation of the P-Cygni profiles of the C II, CIV and Si IV resonance lines. Near periastron passage, the absorption troughs of those resonance-line profiles increase abruptly in strength and width, followed by a gradual decrease. In particular, near periastron the blue black-edges of the P-Cygni absorption troughs shift to larger out ow velocities. We discuss that the apparently larger wind velocity and velocity dispersion observed at periastron could be explained by four phenomena: (i) geometrical resonance-line eclipse effects being the main cause of the observed UV spectral variability, enhanced by sightline crossing of the turbulent wind-wind collision zone; (ii) the possibility of an orbital-plane enhanced WC7 stellar wind; (iii) possible common-envelope acceleration by the combined WC and O stellar radiation fields; and (iv) possible enhanced radiatively driven mass loss due to tidal stresses, focused along the orbiting line of centers. |
| وصف الملف: | application/pdf |
| اللغة: | English |
| تدمد: | 0004-6361 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0c091d9195df428fc56f5c96318a9cdd https://hdl.handle.net/11370/1687b5fc-79a0-4660-bd12-51f7835a6319 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....0c091d9195df428fc56f5c96318a9cdd |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 00046361 |
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