Low- and Medium-Dispersion Spectropolarimetry of Nova V475 Sct (Nova Scuti 2003): Discovery of an Asymmetric High-Velocity Wind in a Moderately Fast Nova

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dc.creatorKawabata, Koji S.
dc.creatorOhyama, Youichi
dc.creatorEbizuka, Noboru
dc.creatorTakata, Tadafumi
dc.creatorYoshida, Michitoshi
dc.creatorIsogai, Mizuki
dc.creatorNorimoto, Yuji
dc.creatorOkazaki, Akira
dc.creatorSaitou, Masashi S.
dc.date2006-04-16
dc.date.accessioned2026-07-07T11:25:30Z
dc.date.available2026-07-07T11:25:30Z
dc.descriptionWe present low-resolution ($R\sim 90$) and medium-resolution ($R\sim 2500$) spectropolarimetry of Nova V475 Sct with the HBS instrument, mounted on the 0.91-m telescope at the Okayama Astrophysical Observatory, and with FOCAS, mounted on the 8.2-m Subaru telescope. We estimated the interstellar polarization toward the nova from the steady continuum polarization components and H$α$ line emission components. After subtracting the interstellar polarization component from the observations, we found that the H$α$ emission seen on 2003 October 7 was clearly polarized. In the polarized flux spectrum, the H$α$ emission had a distinct red wing extending to $\sim +4900$ km s$^{-1}$ and a shoulder around $+3500$ km s$^{-1}$, showing a constant position angle of linear polarization $θ_{\rm *}\simeq 155\arcdeg\pm 15\arcdeg$. This suggests that the nova had an asymmetric outflow with a velocity of $v_{\rm wind}\simeq 3500$ km s$^{-1}$ or more, which is six times higher than the expansion velocity of the ionized shell at the same epoch. Such a high-velocity component has not previously been reported for a nova in the `moderately fast' speed class. Our observations suggest the occurrence of violent mass-loss activity in the nova binary system even during the common-envelope phase. The position angle of the polarization in the H$α$ wing is in good agreement with that of the continuum polarization found on 2003 September 26 ($p_{\rm *}\simeq 0.4$--0.6 %), which disappeared within the following 2 d. The uniformity of the PA between the continuum polarization and the wing polarization on October 7 suggests that the axis of the circumstellar asymmetry remained nearly constant during the period of our observations.
dc.description27 pages, 7 figures, accepted for publication in AJ
dc.identifierhttps://arxiv.org/abs/astro-ph/0604341
dc.identifierhttp://arxiv.org/abs/astro-ph/0604341
dc.identifierAstron.J.132:433-442,2006
dc.identifierdoi:10.1086/505040
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/195527
dc.subjectAstrophysics
dc.titleLow- and Medium-Dispersion Spectropolarimetry of Nova V475 Sct (Nova Scuti 2003): Discovery of an Asymmetric High-Velocity Wind in a Moderately Fast Nova
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