SPHERE dynamical and spectroscopic characterization of HD 142527B
SPHERE dynamical and spectroscopic characterization of HD 142527B
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HD 142527B 的 SPHERE 动力学和光谱表征
DOI：
10.1051/0004-6361/201833990
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发表时间：
2018
影响因子：
6.5
通讯作者：
A. Vigan
中科院分区：
文献类型：
--
作者：
R. Claudi;A. Maire;D. Mesa;A. Cheetham;C. Fontanive;R. Gratton;A. Zurlo;H. Avenhaus;T. Bhowmik;B. Biller;A. Boccaletti;M. Bonavita;M. Bonnefoy;E. Cascone;G. Chauvin;A. Delboulbé;S. Desidera;V. D’Orazi;P. Feautrier;M. Feldt;F. Flammini Dotti;Julien H. Girard;E. Giro;M. Janson;J. Hagelberg;M. Keppler;T. Kopytova;S. Lacour;A. Lagrange;M. Langlois;J. Lannier;H. Le Coroller;F. Ménard;S. Messina;M. Meyer;M. Millward;J. Olofsson;A. Pavlov;S. Peretti;C. Perrot;C. Pinte;J. Pragt;J. Ramos;S. Rochat;L. Rodet;R. Roelfsema;D. Rouan;G. Salter;T. Schmidt;E. Sissa;P. Thebault;S. Udry;A. Vigan
目标。HD 142527是最常被研究的赫比格Ae/Be星之一，它的过渡盘上有一个半径高达100 Au的大空洞。由于这个原因，它已经被纳入了保证时间观测（GTO）的SpHere红外系外行星巡天（SHINE），作为甚大望远镜（VLT）光谱偏振高对比度系外行星研究（SPHERE）的一部分，以寻找可能解释差距存在的低质量伴星。SHINE是一个大型的调查，在大约600个年轻的附近的恒星被观察与球体的目的是限制巨大的行星人口的出现和轨道特性在大（> 5 Au）的轨道分离周围的年轻恒星。
方法.我们使用SPHERE的IRDIFS观测模式（IRDIS是红外双成像光谱仪加IFS或积分场光谱仪的缩写），没有任何日冕仪，以搜索和表征距离该星星30质量的伴星。此外，我们提出了第一个观察，曾经使用稀疏孔径掩模（SAM）的SPHERE在IRDIFS和IRDIFS_EXT模式。所有数据都使用专用的SPHERE管道和专用算法进行简化，这些算法使用主成分分析（PCA）和参考差分成像（RDI）技术。
结果我们在距离星星73 mas（11.4 Au）处探测到吸积的低质量伴星HD 142527 B。在IFS的视场（中心位于恒星上的100 Au）或IRDIS的视场（中心位于星星上的100 Au）中，没有其他质量大于10 MJ的伴星。IFS、SAM IFS和IRDIS的测量结果表明HD 142527 B的光谱类型为M6，光谱子类型的不确定性为一个，与M = 0.11 ± 0.06 M <$和R = 0.15 ± 0.07 R <$的天体兼容。 使用当代进化模型确定质量仍然是一个挑战，因为它们没有考虑到由于下落物质的吸积而产生的能量输入。我们认为次级的谱型也可能早于我们从IFS谱中得到的谱型。从动力学考虑，我们进一步将质量限制为0.26+0.16−0.14 M，这与我们的光谱分析和文献中报道的值一致。根据先前的方法，伴星的动力学质量下限和上限对应于M2.5和M5.5之间的光谱类型。通过对天体测量点的拟合，我们得到了以下轨道参数：周期P = 35 − 137 yr;倾角i = 121 − 130°，交点经度Ω= 124 −135°，近心点分离度的68%置信区间为Au − 18−57 au。 偏心率和通过近心点的时间表现出两组值：e为0.2-0.45和0.45-0.7，T0为0.2015 -2020和0.2020 -2022。虽然这些轨道参数起初可能表明HD 142527 B不是造成外盘截断的伴星，但之前对该系统的流体动力学分析表明，它们与能够产生大空洞和其他观测特征的伴星是相容的。
Aims. HD 142527 is one of the most frequently studied Herbig Ae/Be stars with a transitional disk that hosts a large cavity that is up to about 100 au in radius. For this reason, it has been included in the guaranteed time observation (GTO) SpHere INfrared survey for Exoplanets (SHINE) as part of the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) at the Very Large Telescope (VLT) in order to search for low-mass companions that might explain the presence of the gap. SHINE is a large survey within about 600 young nearby stars are observed with SPHERE with the aim to constrain the occurrence and orbital properties of the giant planet population at large (> 5 au) orbital separation around young stars.
Methods. We used the IRDIFS observing mode of SPHERE (IRDIS short for infrared dual imaging and spectrograph plus IFS or integral field spectrograph) without any coronagraph in order to search for and characterize companions as close as 30 mas of the star. Furthermore, we present the first observations that ever used the sparse aperture mask (SAM) for SPHERE both in IRDIFS and IRDIFS_EXT modes. All the data were reduced using the dedicated SPHERE pipeline and dedicated algorithms that make use of the principal component analysis (PCA) and reference differential imaging (RDI) techniques.
Results. We detect the accreting low–mass companion HD 142527B at a separation of 73 mas (11.4 au) from the star. No other companions with mass greater than 10 MJ are visible in the field of view of IFS (∼100 au centered on the star) or in the IRDIS field of view (∼400 au centered on the star). Measurements from IFS, SAM IFS, and IRDIS suggest an M6 spectral type for HD 142527B, with an uncertainty of one spectral subtype, compatible with an object of M = 0.11 ± 0.06 M⊙ and R = 0.15 ± 0.07 R⊙. The determination of the mass remains a challenge using contemporary evolutionary models, as they do not account for the energy input due to accretion from infalling material. We consider that the spectral type of the secondary may also be earlier than the type we derived from IFS spectra. From dynamical considerations, we further constrain the mass to 0.26+0.16−0.14 M⊙, which is consistent with both our spectroscopic analysis and the values reported in the literature. Following previous methods, the lower and upper dynamical mass values correspond to a spectral type between M2.5 and M5.5 for the companion. By fitting the astrometric points, we find the following orbital parameters: a period of P = 35 − 137 yr; an inclination of i = 121 − 130°, a value of Ω = 124 − 135° for the longitude of node, and an 68% confidence interval of ∼18 − 57 au for the separation at periapsis. Eccentricity and time at periapsis passage exhibit two groups of values: ∼0.2–0.45 and ∼0.45–0.7 for e, and ∼2015–2020 and ∼2020–2022 for T0. While these orbital parameters might at first suggest that HD 142527B is not the companion responsible for the outer disk truncation, a previous hydrodynamical analysis of this system showed that they are compatible with a companion that is able to produce the large cavity and other observed features.
影响因子：
6.5
作者：
Baraffe, Isabelle;Homeier, Derek;Chabrier, Gilles
通讯作者：
Chabrier, Gilles