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arXiv 0804.1212astro-ph
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MWC 297:一颗以临界速度旋转的年轻大质量恒星

MWC 297: a young high-mass star rotating at critical velocity

B. Acke, T. Verhoelst, M. E. van den Ancker, P. Deroo, C. Waelkens, O. Chesneau, E. Tatulli, M. Benisty, E. Puga, L. B. F. M. Waters, A. Verhoeff, A. de Koter

摘要:

MWC 297是一颗年轻的大质量B[e]星。中心恒星有一个350 km/s的大投影旋转速度。尽管发表了大量的观测结果,但这个物体的性质及其富含尘埃的环境还没有得到很好的理解。与本论文中,我们阐明了产生近中红外通量过剩的拱星物质的几何结构,并构建了源的外观和演化状态的整体图像。用ESO干涉光谱仪AMBER和EWB探测MWC 297的H、K和N波段亮度分布。我们已经获得了能见度测量3琥珀色和12琥珀色基线,涵盖了广泛的空间频率。我们用一个由三个不同范围和亮温的高斯圆盘组成的几何模型重建了H、K和N的亮度分布。该模型可以解释MWC 297的整个近中红外发射。近红外和中红外辐射,包括10微米的硅酸盐辐射,来自中央恒星周围非常紧凑的区域(半高宽< 1.5天文单位)。我们认为,在MWC 297系统中的拱星物质是组织在一个磁盘,在中等(i < 40度)的倾角。在我们的干涉测量数据的分辨率下,磁盘没有显示内部无发射间隙。盘的低倾角意味着恒星的实际旋转速度超过了它的临界速度。我们讨论了这一结果的影响,在高质量恒星的形成,和经典Be星的主序星演化。

英文摘要:

MWC 297 is a young massive nearby B[e] star. The central star has a large projected rotational velocity of 350 km/s. Despite the wealth of published observations, the nature of this object and its dust-rich surroundings is not well understood. With the present paper, we shed light on the geometrical structure of the circumstellar matter which produces the near- to mid-infrared flux excess, and construct an overall image of the source's appearance and evolutionary status. The H-, K- and N-band brightness distribution of MWC 297 is probed with the ESO interferometric spectrographs AMBER and MIDI. We have obtained visibility measurements on 3 AMBER and 12 MIDI baselines, covering a wide range of spatial frequencies. We have reconstructed the brightness distribution in H, K and N with a geometric model consisting of three Gaussian disks with different extent and brightness temperature. This model can account for the entire near- to mid-IR emission of MWC 297. The near- and mid-IR emission, including the silicate emission at 10 micron, emanates from a very compact region (FWHM < 1.5 AU) around the central star. We argue that the circumstellar matter in the MWC 297 system is organized in a disk, seen under moderate (i < 40 deg) inclination. The disk displays no inner emission-free gap at the resolution of our interferometric data. The low inclination of the disk implies that the actual rotational velocity of the star exceeds its critical velocity. We discuss the impact of this result in terms of the formation of high-mass stars, and the main-sequence evolution of classical Be stars.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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