Accretion Signatures from Massive Young Stellar Objects
Accretion Signatures from Massive Young Stellar Objects
复制标题
巨大年轻恒星物体的吸积特征
DOI：
10.1086/425680
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
National Optical Astronomy Observatory
中科院分区：
文献类型：
--
作者：
R. Blum;C. Barbosa;A. Damineli;P. Conti;S. Observatory;U. S. Paulo;Jila;U. Colorado;National Optical Astronomy Observatory
提供了大质量、嵌入式、年轻恒星物体的高分辨率（λ/Δλ = 50，000）K波段光谱。目前的样本包括四个大质量的年轻恒星位于新生的星系团，为银河系巨大的H II区域提供动力。观测到CO分子2.3 μ m2 -0振转带头的辐射。在三个物体中看到的一系列速度加宽的轮廓与在各种倾角下看到的拱星盘所产生的发射一致。Brγ谱支持吸积盘或环面模型的大质量恒星的光谱和空间分辨率相同。在第四个天体中，观测到了Br辐射，暗示着一个旋转的环面，但是CO的轮廓很窄，这表明在大质量恒星中可能有不同的CO辐射机制;这与BN天体和MWC 349的早期观测结果一致。到目前为止，只有O型晚期或B型早期的年轻大质量恒星在这样的嵌入星团中被发现有明显的吸积盘特征。这些恒星通常是在其他更大质量的恒星存在的情况下被发现的，这些恒星的光球光谱显示出它们的存在，但没有表现出盘的特征。这表明它们的吸积盘消散的时间尺度比质量较小的OB星快得多，或者质量最大的恒星不形成吸积盘。
High-resolution (λ/Δλ = 50,000) K-band spectra of massive, embedded, young stellar objects are presented. The present sample consists of four massive young stars located in nascent clusters powering Galactic giant H II regions. Emission in the 2.3 μm 2-0 vibrational-rotational band head of CO is observed. A range of velocity-broadened profiles seen in three of the objects is consistent with the emission arising from a circumstellar disk seen at various inclination angles. Brγ spectra that support an accretion disk or torus model for massive stars of the same spectral and spatial resolution are also presented. In the fourth object, Br emission suggesting a rotating torus is observed, but the CO profile is narrow, indicating that there may be different CO emission mechanisms in massive stars; this is consistent with earlier observations of the BN object and MWC 349. To date, only young massive stars of late O or early B types have been identified with clear accretion disk signatures in such embedded clusters. Often such stars are found in the presence of other, more massive stars that are revealed by their photospheric spectra but exhibit no disk signatures. This suggests that the timescale for dissipating their disks is much faster than that of the less massive OB stars or that the most massive stars do not form with accretion disks.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell