arXiv 0901.03472009-01-04astro-ph.SR

Herbig Ae/Be星的磁性

Magnetism of Herbig Ae/Be stars

G. A. Wade, E. Alecian, J. Grunhut, C. Catala, S. Bagnulo, C. P. Folsom, J. D. Landstreet

备注：: 13 pages, 7 figs, proceedings of "Astronomical Polarimetry 2008: From small to large telescopes" (invited presentation)

摘要：

在主序前阶段观测恒星的磁场，可以为恒星形成后期的复杂物理学提供重要的新见解。在中等质量的恒星中尤其如此，那里的磁场很强，而且是全球性的，因此最适合直接研究。最近的圆偏振光谱观测的前主序赫比格Ae/Be星揭示了存在组织磁场的光球这些对象的一小部分。到目前为止，已经探测到9颗磁性HAeBe星，并且这些探测得到了反复观测的证实。它们的Stokes V特征的形态和变化表明，它们的磁场具有重要的kG强度的偶极子分量，并且偶极子在至少几年的时间尺度上是稳定的。这些磁星表现出大范围的恒星质量，从2-13太阳质量，和不同的旋转特性，vsini从几公里/秒到200公里/秒。大多数的磁性HAeBe星显示出近似太阳的丰度;它们显然一般不表现出磁性主序星A和B型（Ap/Bp星）的强烈和系统的特性。观测到的HAeBe磁性恒星的整体入射率约为7%，这个值与主序上中等质量磁性恒星的入射率一致。这种低发生率与通常涉及磁介导的吸积的地层情况不一致。前主序星和主序星中等质量恒星的磁性之间的相似性似乎与这些天体中磁性的化石起源的假设是一致的。

英文摘要：

Observations of magnetic fields of stars at the pre-main sequence phase can provide important new insights into the complex physics of the late stages of star formation. This is especially true at intermediate stellar masses, where magnetic fields are strong and globally organised, and therefore most amenable to direct study. Recent circularly-polarised spectroscopic observations of pre-main sequence Herbig Ae/Be stars have revealed the presence of organised magnetic fields in the photospheres of a small fraction of these objects. To date, 9 magnetic HAeBe stars have been detected, and those detections confirmed by repeated observations. The morphology and variability of their Stokes V signatures indicates that their magnetic fields have important dipole components of kG strength, and that the dipole is stable on timescales ofat least years. These magnetic stars exhibit a large range of stellar mass, from about 2-13 solar masses, and diverse rotational properties, with vsini from a few km/s to 200 km/s. Most magnetic HAeBe stars show approximately solar abundances; they clearly do not generally exhibit the strong and systematic peculiarities of the magnetic main sequence A and B type stars (the Ap/Bp stars). The observed fractional bulk incidence of magnetic HAeBe stars is about 7%, a value compatible with the incidence of magnetic intermediate-mass stars on the main sequence. This low incidence is at odds with formation scenarios generally involving magnetically-mediated accretion. The similarily between the magnetic properties of the pre-main sequence and main sequence intermediate-mass stars appears compatible with the hypothesis of a fossil origin of magnetism in these objects.

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。

摘要：

英文摘要：

相关论文