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首页> 外文期刊>The Astrophysical journal >DIAGNOSING MASS FLOWS AROUND HERBIG Ae/Be STARS USING THE HE I λ10830 LINE
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DIAGNOSING MASS FLOWS AROUND HERBIG Ae/Be STARS USING THE HE I λ10830 LINE

机译:使用HE Iλ10830线诊断围绕草药Ae / Be星的质量流

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摘要

We examine He I λ10830 profile morphologies for a sample of 56 Herbig Ae/Be stars (HAEBES). We find significant differences between HAEBES and classical T-Tauri stars (CTTS) in the statistics of both blueshifted absorption (i.e., mass outflows) and redshifted absorption features (i.e., mass infall or accretion). Our results suggest that, in general, Herbig Be (HBe) stars do not accrete material from their inner disks in the same manner as CTTS, which are believed to accrete material via magnetospheric accretion, whereas Herbig Ae (HAe) stars generally show evidence for magnetospheric accretion. We find no evidence in our sample of narrow blueshifted absorption features, which are typical indicators of inner disk winds and are common in He I λ10830 profiles of CTTS. The lack of inner-disk-wind signatures in HAEBES, combined with the paucity of detected magnetic fields on these objects, suggests that accretion through large magnetospheres that truncate the disk several stellar radii above the surface is not as common for HAe and late-type HBe stars as it is for CTTS. Instead, evidence is found for smaller magnetospheres in the maximum redshifted absorption velocities in our HAEBE sample. These velocities are, on average, a smaller fraction of the system escape velocity than is found for CTTS, suggesting accretion is taking place closer to the star. Smaller magnetospheres, and evidence for boundary layer accretion in HBe stars, may explain the less common occurrence of redshifted absorption in HAEBES. Evidence is found that smaller magnetospheres may be less efficient at driving outflows compared to CTTS magnetospheres.
机译:我们研究了56个Herbig Ae / Be星(HAEBES)的He Iλ10830轮廓形态。我们在蓝移吸收(即质量流出)和红移吸收特征(即质量下降或吸积)的统计中发现了HAEBES和经典T-Tauri星(CTTS)之间的显着差异。我们的结果表明,通常,Hertig Be(HBe)恒星不会像CTTS那样从其内盘中吸收物质,而CTTS被认为是通过磁层增生来吸收物质的,而Herbig Ae(HAe)恒星通常会显示出磁层吸积。在我们的样本中,没有发现狭窄的蓝移吸收特征的证据,这些特征是内盘风的典型指示,并且在CTTS的He Iλ10830剖面中很常见。 HAEBES中缺乏内盘风特征,再加上在这些物体上检测到的磁场不足,表明通过大磁层将表面上方几个恒星半径截断的大磁层积聚对于HAe和晚期型并不常见。 HBe是CTTS的明星。取而代之的是,在我们的HAEBE样本中发现了最大磁移吸收速度中较小磁层的证据。平均而言,这些速度是系统逃逸速度的一部分,比CTTS所发现的要小,这表明吸积发生在更靠近恒星的地方。较小的磁层和HBe恒星中边界层积聚的证据可能解释了HAEBES中红移吸收的发生较不常见。有证据表明,与CTTS磁层相比,较小的磁层在驱动流出方面可能效率较低。

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