Godon Patrick, Sion Edward M, Starrfield Sumner, Livio Mario, Williams Robert E, Woodward Charles E, Kuin Paul, Page Kim L
Astronomy & Astrophysics, Villanova University, Villanova, PA 19085, USA.
School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA.
Astrophys J Lett. 2014 Apr 1;784(No 2). doi: 10.1088/2041-8205/784/2/L33. Epub 2014 Mar 19.
With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis (T Pyx) 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 10 to 3.3 × 10, and assuming a mass accretion rate of 10-10 yr for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained 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 (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of ( - ) = 0.35 (based on combined and spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ≤ (-) ≤ 0.50) and white dwarf mass (0.70 ≤ ≤ 1.35 ) the accreted mass is larger than the ejected mass. Only for a low reddening (0.25 and smaller) a large white dwarf mass (0.9 and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening.
作为典型的再发新星，北冕座T星（T Pyx）有六次记录在案的新星爆发，是评估新星周期内白矮星质量净变化的理想激变变星系统。近期对2011年爆发时抛出物质质量的估计范围在约10到3.3×10之间，假设在44年里吸积率为10-10 年，得出的结论是北冕座T星中的白矮星实际上在损失质量。利用非局部热动平衡盘模型光谱来拟合我们最近获得的COS和STIS光谱，我们发现吸积率比之前估计的大两个数量级。我们得出的更大吸积率主要归因于新测定的北冕座T星距离（4.8千秒差距，大于之前估计的3.5千秒差距）、我们得出的色指数（-）=0.35（基于组合的和光谱）以及非局部热动平衡盘模型（与早期工作中的黑体和原始流量估计相比）。我们发现，对于大多数色指数值（0.25≤（-）≤0.50）和白矮星质量值（0.70≤≤1.35 ），吸积的质量大于抛出的质量。只有在低色指数（约0.25及更小）和大白矮星质量（0.9及更大）的情况下，抛出的质量才大于吸积的质量。然而，对于更大的色指数值能得到最佳结果。
