Classical Novae as a Probe of the Cataclysmic Variable Population
Classical Novae as a Probe of the Cataclysmic Variable Population
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经典新星作为灾难性变种群的探针
DOI：
10.1086/430594
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
L. Bildsten
中科院分区：
文献类型：
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作者：
D. Townsley;L. Bildsten
经典新星(CNE)是激变变星(CV)中质量转移到白矮星(WD)上最明亮的表现。因此，在这些相互作用的双星中，它们是质量传输率Ṁ和WD质量MWD的探测器。我们对CN点火质量Mign与Ṁ和MWD的依赖关系的计算得出了这些爆炸的重复时间。我们发现，观测到的CNE轨道周期分布与中断的磁制动演化情景是一致的，在轨道周期PORT&>3小时，质量转移是由伴星风的角动量损失驱动的，而在PORT&L；3小时是由引力辐射驱动的。大约50%的CNE出现在Ṁ≃10-9M☉yr-1处积累的二进制中，PORb=3-4小时，其余50%在PORB较长(较高Ṁ)和较短(较低Ṁ)之间平均分配。不同CV对CN速率的相对贡献率的解析告诉我们，每年需要3(9)×10~5个具有WD MASS 1.0(0.6)M☉的CV来产生一个CN。此外，每年一个CN需要1(2)×10-4yr-1的CV出生率，并可能以Ṁ=3(9)×10-5M☉yr-1的速率向星际介质抛射质量。利用在外部星系中测量的K带特定的CN率，我们发现了每1010个L☉，K的CV出生率为2(4)×10-4yr-1，这与椭圆星系中光度特定的Ia型超新星的速率非常相似。同样，我们预测，在一个古老的恒星群体中，每106名L☉，K应该有60-180份简历。球状星系团47TUC中X射线识别的CV的数量与这个数字相似，显示出相对于磁场没有过剩。观察到的CN PORB分布也包含没有周期间隔的CV种群的证据。这些可能是具有强磁场WD(极点)的系统，其中已被认为磁场干扰伴星的风，将角动量损失限制为引力辐射的角动量损失，并消除周期间隙。随着Ṁ的降低，极点的演化速度比经历磁制动的系统要慢。使用CV演化的两组分稳态模型，我们证明了具有磁性的CV的比例(22%)意味着相对于非磁性的CV的出生率为8%，类似于强磁场WDS的比例。
Classical novae (CNe) are the brightest manifestation of mass transfer onto a white dwarf (WD) in a cataclysmic variable (CV). As such, they are probes of the mass transfer rate, Ṁ, and WD mass, MWD, in these interacting binaries. Our calculations of the dependence of the CN ignition mass, Mign, on Ṁ and MWD yields the recurrence times of these explosions. We show that the observed CNe orbital period distribution is consistent with the interrupted magnetic braking evolutionary scenario, in which at orbital periods Porb > 3 hr mass transfer is driven by angular momentum loss via a wind from the companion star, and at Porb < 3 hr by gravitational radiation. About 50% of CNe occur in binaries accreting at Ṁ ≃ 10-9 M☉ yr-1 with Porb = 3 - 4 hr, with the remaining 50% split evenly between Porb longer (higher Ṁ) and shorter (lower Ṁ) than this. This resolution of the relative contribution to the CN rate from different CVs tells us that 3(9) × 105 CVs with WD mass 1.0(0.6) M☉ are needed to produce one CN per year. In addition, one CN per year requires a CV birthrate of 1(2) × 10-4 yr-1 and likely ejects mass into the interstellar medium at a rate of Ṁ = 3(9) × 10-5 M☉ yr-1. Using the K-band-specific CN rate measured in external galaxies, we find a CV birthrate of 2(4) × 10-4 yr-1 per 1010 L☉,K, very similar to the luminosity specific Type Ia supernova rate in elliptical galaxies. Likewise, we predict that there should be 60-180 CVs for every 106 L☉,K in an old stellar population. The population of X-ray-identified CVs in the globular cluster 47 Tuc is similar to this number, showing no overabundance relative to the field. The observed CN Porb distribution also contains evidence for a CV population that has no period gap. These are likely systems with a strongly magnetic WD (polars) in which it has been suggested that the field interferes with the wind of the companion, limiting angular momentum losses to those of gravitational radiation and eliminating the period gap. With this reduced Ṁ, polars evolve more slowly than systems that undergo magnetic braking. Using a two-component steady state model of CV evolution, we show that the fraction of CVs that are magnetic (22%) implies a birthrate of 8% relative to nonmagnetic CVs, similar to the fraction of strongly magnetic field WDs.