Protoplanetary Disks of T Tauri Binary Systems in the Orion Nebula Cluster
Protoplanetary Disks of T Tauri Binary Systems in the Orion Nebula Cluster
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DOI：
10.1051/0004-6361/201118314
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发表时间：
2012-01
影响因子：
6.5
通讯作者：
S. Daemgen;S. Correia;M. Petr-Gotzens
中科院分区：
文献类型：
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作者：
S. Daemgen;S. Correia;M. Petr-Gotzens
目标。我们对著名的猎户座星云团（ONC）中空间分辨的低质量联星中的原行星盘进行了研究，以评估联星对星周盘性质的影响。这是目前在高恒星密度恒星形成环境中进行的最大规模的研究，而以前的研究主要集中在年轻的低恒星密度金牛座协会。我们的特别目标是确定存在的磁层吸积和尘埃盘的每个二进制组件，并测量整体磁盘的频率。方法.我们进行了空间分辨的自适应光学辅助艾德观测，以获得近红外测光和光谱的26个双星在ONC，并确定恒星参数，如有效温度，光谱类型，光度和质量，以及吸积特性和近红外过剩的个别二进制组件。在我们的中分辨率K波段光谱的基础上，我们通过测量Brackett-γ发射的强度来推断每个双星组件周围磁层吸积的存在。ONC双星之间的吸积盘频率，然后估计贝叶斯统计。观测到的磁盘签名，测量accret离子光度，和质量吸积率进行了调查d相对于二进制分离，质量比，和到中心的ONC的距离。结果样本中40 + 10 − 9%的双星成分可以被推断为拥有吸积盘的金牛T星。这只是略小于ONC中50%的单星盘部分。我们发现，磁盘在宽的双星的分离>200 Au是一致的随机配对，而在密切的双星（分离<200 Au）观察到的演变的环主星和环主星盘是同步的。环双星盘似乎不适合解释这种差异。此外，我们确定了几个混合对吸积和非吸积组件，这表明这些系统是常见的，并没有偏好或多或少的大规模组件，以更快地发展。导出的吸积光度和质量吸积率的ONC的二进制组件是类似的幅度为ONC的单星和金牛座恒星形成区的双星。本文最后讨论了年轻的双星系统中存在的内吸积盘和恒星倍数中存在的行星之间的联系（可能是弱的）。
Aims. We present a study of protoplanetary disks in spatially resolved low-mass binary stars in the well-known Orion Nebula Cluster (ONC) to assess the impact of binarity on the properties of circumstellar disks. This is currently the largest such study in a clustered high-stellar-density star-forming environment, as opposed to previous studies, which have mostly been focussed on the young, lowstellar-density Taurus association. We particularly aim t o determine the presence of magnetospheric accretion and dust disks for each binary component, and measure the overall disk frequency. Methods. We carried out spatially resolved adaptive-optics-assist ed observations to acquire near-infrared photometry and spectroscopy of 26 binaries in the ONC, and determine stellar parameters such as effective temperatures, spectral types, luminosities, and masses, as well as accretion properties and near-infrared excesses for the individual binary components. On the basis of our medium resolution K-band spectroscopy, we infer the presence of magnetospheric accretion around each binary component by measuring the strength of the Brackett-γ emission. The accretion disk frequency among the ONC binaries is then estimated from Bayesian statistics. The observed disk signatures, measured accret ion luminosities, and mass accretion rates are investigate d with respect to the binary separation, mass ratios, and distance to the center o f the ONC. Results. A fraction of 40 +10 −9 % of the binary components in the sample can be inferred to be T Tauri stars possessing an accretion disk. This is only marginally smaller than the disk fraction of single stars of∼50% in the ONC. We find that disks in wide binaries of >200 AU separation are consistent with random pairing, while the evolution of circumprimary and circumsecondary disks is observed to be synchronized in close binaries (separations <200AU). Circumbinary disks appear to be unsuitable to explain this difference. Furthermore, we identify several mixed pairs of accreting and non-accreting components, suggesting that these systems are common and that there is no preference for either the more or less massive component to evolve faster. The derived accretion luminosities and mass accretion rates of the ONC binary components are of similar magnitude as those for both ONC single stars and binaries in the Taurus star-forming region. The paper concludes with a discussion of the (presumably weak) connection between the presence of inner accretion disks in young binary systems and the existence of planets in stellar multiples.