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arXiv 1402.0128astro-ph.SR
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哈勃空间望远镜对复发新星T的远紫外光谱分析

Hubble Space Telescope Far Ultraviolet Spectroscopy of the Recurrent Nova T Pyxidis

P. Godon, E. M. Sion, S. Starrfield, M. Livio, R. E. Williams, C. E. Woodward, P. Kuin, K. L. Page

摘要:

有六个记录的新星爆发,原型复发新星T Pyxtanes是理想的激变变量系统,以评估净变化的白矮星质量在一个新星周期。最近对2011年爆发中喷射出的质量的估计从几个1.E-5 sollar质量到3.3E-4 sollar质量不等,并假设44年的质量吸积速率为1.E-8到1.E-7 Sollar质量/年,得出的结论是T Pyx中的白色dwaf实际上正在失去质量。使用NLTE磁盘建模光谱,以适应我们最近获得的哈勃太空望远镜(HST)COS和STIS光谱,我们发现一个质量吸积率高达两个数量级大于先前估计。我们更大的质量吸积率主要是由于新推导出的T Pyx距离(4.8kpc; Sokoloski et al. 2013,大于之前的3.5kpc估计),我们推导出的E(B-V)=0.35的红化(基于IUE和GALEX光谱的组合)和NLTE盘模型(与早期工作中的黑体和原始通量估计相比)。我们发现,对于红化(0.25 < E(B-V)< 0.50)和白dwaf质量(0.70 ~ 1.35 Sollar质量)的大多数值,吸积质量大于喷射质量。只有在低红化(0.25或更小)和大的白色dwaf质量(0.9 sollar质量或更大)相结合的情况下,喷出的质量才大于吸积的质量。然而,最好的光谱拟合的结果是获得一个较大的红化值。

英文摘要:

With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis is the ideal cataclysmic variable system to assess the net change of the white dwarf mass within a nova cycle. Recent estimates of the mass ejected in the 2011 outburst ranged from a few 1.E-5 sollar mass to 3.3E-4 sollar mass, and assuming a mass accretion rate of 1.E-8 to 1.E-7 Sollar mass/yr for 44yrs, it has been concluded that the white dwaf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope (HST) COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8kpc; Sokoloski et al. 2013, larger than the previous 3.5kpc estimate), our derived reddening of E(B-V)=0.35 (based on combined IUE and GALEX spectra) and NLTE disk modeling (compared to black body and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 < E(B-V) < 0.50) and white dwaf mass (0.70 to 1.35 Sollar mass) the accreted mass is larger than the ejected mass. Only for a low reddening (0.25 and smaller) combined with a large white dwaf mass (0.9 sollar mass and larger) is the ejected mass larger than the accreted one. However, the best spectral fitting results are obtained for a larger value of the reddening.

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