High‐Dispersion Spectroscopy of the X‐Ray Transient RXTE J0421+560 (=CI Camelopardalis) during Outburst
| العنوان: | High‐Dispersion Spectroscopy of the X‐Ray Transient RXTE J0421+560 (=CI Camelopardalis) during Outburst |
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| المؤلفون: | Inese I. Ivans, W. F. Welsh, Edward L. Robinson |
| المصدر: | The Astrophysical Journal. 565:1169-1182 |
| بيانات النشر: | American Astronomical Society, 2002. |
| سنة النشر: | 2002 |
| مصطلحات موضوعية: | Physics, Solar mass, X-ray transient, Astrophysics::High Energy Astrophysical Phenomena, Extinction (astronomy), Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Circumstellar envelope, Compact star, Luminosity, Neutron star, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Supergiant, Astrophysics::Galaxy Astrophysics |
| الوصف: | We obtained high dispersion spectra of CI Cam, the optical counterpart of XTE J0421+560, two weeks after the peak of its short outburst in 1998 April. The optical counterpart is a supergiant B[e] star emitting a two-component wind. The cool wind (the source of narrow emission lines of neutral and ionized metals) has a velocity of 32 km/s and a temperature near 8000 K. Dense and roughly spherical, it fills the space around the sgB[e] star, and, based on the size of an infrared-emitting dust shell around the system, extends to a radius between 13 - 50 AU. It carries away mass at a high rate, Mdot > 10^(-6) solar masses per year. The hot wind has a velocity in excess of 2500 km/s and a temperature of 1.7 +/-0.3 x 10^4 K. From UV spectra of CI Cam obtained in 2000 March with Hubble Space Telescope, we derive a differential extinction E(B-V) = 0.85 +/- 0.05. We derive a distance to CI Cam > 5 kpc. Based on this revised distance, the X-ray luminosity at the peak of the outburst was L(2-25 keV) > 3.0 x 10^38 erg/s, making CI Cam one of the most luminous X-ray transients. The ratio of quiescent to peak luminosity in the 2 - 25 keV band is < 1.7 x 10^(-6). The compact star in CI Cam is immersed in the dense circumstellar wind from the sgB[e] star and burrows through the wind producing little X-ray emission except for rare transient outbursts. This picture (a compact star traveling in a wide orbit through the dense circumstellar envelope of a sgB[e] star, occasionally producing transient X-ray outbursts) makes CI Cam unique among the known X-ray binaries. Strong circumstantial evidence suggests that the compact object is a black hole, not a neutron star. We speculate that the X-ray outburst was short because the accretion disk around the compact star is fed from a stellar wind and is smaller than disks fed by Roche-lobe overflow. |
| تدمد: | 1538-4357 0004-637X |
| DOI: | 10.1086/324715 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::c0f38734d48c11224d2a98d7dc9489f2 https://doi.org/10.1086/324715 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi...........c0f38734d48c11224d2a98d7dc9489f2 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15384357 0004637X |
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| DOI: | 10.1086/324715 |