The Pistol Star
The Pistol Star
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手枪之星
DOI：
10.1086/306237
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
N. Langer
中科院分区：
文献类型：
--
作者：
D. Figer;F. Najarro;M. Morris;I. McLean;T. Geballe;A. Ghez;N. Langer
我们提出了新的近红外数据和分析，这表明手枪星星是已知的最明亮的恒星之一，增加了另一个大质量星星形成和恒星演化理论的测试点。我们利用年轻的五重星团中星星和周围恒星的近红外颜色估计消光系数为AK = 3.2 ± 0.5。使用我们的风/大气代码，我们发现两个家庭的模型，适合的光谱能量分布和详细的线轮廓。低光度模型给出L = 106.6±0.2 L返和Teff = 104.15±0.01 K，而高光度模型给出L = 107.2±0.2 L返和Teff = 104.33±0.01 K;光度误差假设AK的不确定度为±0.5，而Teff的误差受到详细的线模型的限制。这些模型还揭示了一个富含氦的表面。由于先前存在的恒星演化模型没有扩展到如此高的光度，我们采用新的非常大质量的恒星的演化轨道来确定手枪星星的初始质量和年龄，并估计Minitial = 200-250 M，年龄为1.7-2.1百万年。由亮度和温度推断，该星星在H-R图上处于一个经常发现亮蓝变星（LBV）的稀疏区域，这与我们的演化模型预测的该星星处于不稳定演化阶段是一致的。我们将这颗星星及其周围的星云解释为最近喷射出大量物质的LBV。我们的K波段散斑成像数据显示，这颗星星是一颗单星，预计距离为110 Au。
We present new near-infrared data and analysis, which indicate that the Pistol Star is one of the most luminous stars known, adding another test point for massive star formation and stellar evolution theories. We estimate an extinction of AK = 3.2 ± 0.5 using the near-infrared colors of the star and of surrounding stars in the young Quintuplet cluster. Using our wind/atmosphere code, we find two families of models that fit the spectral energy distribution and detailed line profiles. The lower luminosity models give L = 106.6±0.2 L☉ and Teff = 104.15±0.01 K, while the higher luminosity models give L = 107.2±0.2 L☉ and Teff = 104.33±0.01 K; the error in luminosity assumes an uncertainty of ±0.5 in AK, while the error in Teff is constrained by detailed line modeling. The models also reveal a helium enriched surface. As previously existing stellar evolution models do not extend to such high luminosities, we employ new evolutionary tracks for very massive stars to determine the initial mass and age of the Pistol Star, and estimate Minitial = 200-250 M☉ and an age of 1.7-2.1 Myr. The inferred luminosity and temperature place the star in a sparsely populated zone in the H-R diagram where luminous blue variables (LBVs) are often found. This is consistent with our evolutionary models, which predict that the star is in an unstable evolutionary stage. We interpret the star and its surrounding nebula as an LBV that has recently ejected large amounts of material. Our K-band speckle-imaging data reveal the star to be single down to a projected separation of 110 AU.