An excess of massive stars in the local 30 Doradus starburst-猫眼课题宝

DOI：

10.1126/science.aan0106

发表时间：

2018-01

期刊：

Science

影响因子：

56.9

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

F. Schneider;H. Sana;C. Evans;J. Bestenlehner;J. Bestenlehner;N. Castro;L. Fossati;G. Gräfener;N. Langer;O. Ramírez-Agudelo;C. Sabín-Sanjulián;S. Simón-Díaz;S. Simón-Díaz;F. Tramper;P. Crowther;A. D. Koter;A. D. Koter;S. D. Mink;P. Dufton;María García;M. Gieles;V. Hénault-Brunet;V. Hénault-Brunet;A. Herrero;A. Herrero;R. Izzard;V. Kalari;D. Lennon;J. M. Apellániz;N. Markova;F. Najarro;P. Podsiadlowski;P. Podsiadlowski;J. Puls;W. Taylor;J. V. Loon;J. Vink;C. Norman;C. Norman

观测更多质量的恒星在每个质量下形成的恒星数量被称为初始质量函数（IMF）。对于大多数质量，IMF遵循幂律分布，由Edwin Salpeter在1955年首次确定。施耐德等人利用附近恒星形成区剑鱼座30（也称为蜘蛛星云）的观测结果，并结合恒星模型来确定其IMF。他们发现了比Salpeter分布预测的更多超过30个太阳质量的恒星。因为质量最大的恒星对周围环境的影响也最大例如，通过紫外线辐射、恒星风、超新星爆炸和重元素的产生这种过剩将产生广泛的影响。对恒星形成区域的观测表明，比标准模型预测的更多的恒星形成超过30个太阳质量。大麦哲伦星云中的剑鱼座30恒星形成区是遥远宇宙中大型恒星形成事件的邻近模拟。我们确定了最近的形成历史和初始质量函数（IMF）的大质量恒星在30剑鱼座的光谱观测的基础上，247颗恒星的质量超过15个太阳质量（M）。大质量星星形成的主要阶段开始于大约800万年前（My），而恒星形成的速度似乎在过去的1 My中有所下降。IMF的采样密度高达200 M，包含的30 M以上的恒星比标准Salpeter IMF预测的多32 ± 12%。在15 ~ 200 M的质量范围内，IMF幂律指数为1.90−0.26+0.37，比萨尔彼得指数2.35要浅。

Observing more massive stars The number of stars that form at each mass is known as the initial mass function (IMF). For most masses, the IMF follows a power-law distribution, first determined by Edwin Salpeter in 1955. Schneider et al. used observations of the nearby star-forming region 30 Doradus (also known as the Tarantula Nebula) and combined these with stellar modeling to determine its IMF. They found more stars above 30 solar masses than predicted by the Salpeter distribution. Because the most massive stars also have the biggest influence on their surroundings—for instance, through ultraviolet radiation, stellar winds, supernova explosions, and production of heavy elements—this excess will have wide-ranging implications. Science, this issue p. 69 Observations of a star-forming region show that more stars form in excess of 30 solar masses than predicted by standard models. The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses (M☉). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 M☉ and contains 32 ± 12% more stars above 30 M☉ than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 M☉, the IMF power-law exponent is 1.90−0.26+0.37, shallower than the Salpeter value of 2.35.

An excess of massive stars in the local 30 Doradus starburst

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