RR Pic (1925): a Chandra X-ray view |
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| Authors: | Y Pekön &#; Balman |
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| Institution: | Department of Physics, Middle East Technical University, InönüBulvar?, Ankara 06531, Turkey |
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| Abstract: | We present the Chandra ACIS-S3 data of the old classical nova RR Pic (1925). The source has a count rate of 0.067 ± 0.002 count s?1 in the 0.3–5.0 keV energy range. We detect the orbital period of the underlying binary system in the X-ray wavelengths. We also find that the neutral hydrogen column density differs for orbital minimum and orbital maximum spectra with values 0.25+0.23?0.18× 1022 and 0.64+0.13?0.14× 1022 cm?2 at 3σ confidence level. The X-ray spectrum of RR Pic can be represented by a composite model of bremsstrahlung with a photoelectric absorption, two absorption lines centered around 1.1–1.4 keV and five Gaussian lines centered at emission lines around 0.3–1.1 keV corresponding to various transitions of S, N, O, C, Ne and Fe. The bremsstrahlung temperature derived from the fits ranges from 0.99 to 1.60 keV and the unabsorbed X-ray flux is found to be 2.5+0.4?1.2× 10?13 erg cm?2 s?1 in the 0.3–5.0 keV range with a luminosity of 1.1 ± 0.2 1031 erg s?1 at 600 pc. We also detect excess emission in the spectrum possibly originating from the reverse shock in the ejecta. A fit with a cooling flow plasma emission model shows enhanced abundances of He, C, N, O and Ne in the X-ray emitting region indicating existence of diffusive mixing. |
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| Keywords: | binaries: close stars: individual: RR Pic novae cataclysmic variables stars: rotation white dwarfs X-rays: stars |
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