论文标题
中间质量T托里Star HQ Tau中的磁层增生
Magnetospheric accretion in the intermediate-mass T Tauri star HQ Tau
论文作者
论文摘要
语境。经典的T Tauri恒星(CTT)是被吸积盘包围的序列序列星。它们具有强烈的磁场,并且随着年轻磁星与磁盘相互作用,磁层积聚和射血过程也会发展。研究这种相互作用是理解年轻恒星及其进化的主要目标。目标。这项研究的目的是研究年轻的恒星系统HQ Tau的增生过程,这是一种中间质量T Tauri Star(1.9 m $ _ {\ odot} $)。方法。使用Kepler-K2和互补光曲线以及从CFHT上使用espadons获得的高分辨率光谱时间序列,从光度学上研究了系统的时间变异性。结果。准螺体开普勒-K2光曲线的周期为2.424 d,我们将其归因于恒星的旋转周期。系统的径向速度显示出相同的周期性,就像通过表面斑点对光晶线轮廓的调制所预期的那样。由于出现逆P Cygni组件,在几个发射线(例如HI,CAII,NAI)的红翼中发现了类似的时期。在线剖面中还可以看到流出的签名,有些是周期性的,有些是短暂的。极化分析表明一个复杂的,中等强的磁场,可能足以将内部磁盘截断接近旋转半径,r $ _ {cor} $ $ \ sim $ \ sim $ 3.5 r $ _ {\ star} $。此外,我们报告HQ Tau是光谱二进制候选者,其轨道仍有待确定。结论。这项研究的结果扩展了先前报道的低质量T牛tauri恒星的结果,因为它们表明磁层积聚过程仍可能在中等质量的预纳中序列星(例如HQ TAU)中运行。
Context. Classical T Tauri stars (cTTs) are pre-main sequence stars surrounded by an accretion disk. They host a strong magnetic field, and both magnetospheric accretion and ejection processes develop as the young magnetic star interacts with its disk. Studying this interaction is a major goal toward understanding the properties of young stars and their evolution. Aims. The goal of this study is to investigate the accretion process in the young stellar system HQ Tau, an intermediate-mass T Tauri star (1.9 M$_{\odot}$). Methods. The time variability of the system is investigated both photometrically, using Kepler-K2 and complementary light curves, and from a high-resolution spectropolarimetric time series obtained with ESPaDOnS at CFHT. Results. The quasi-sinusoidal Kepler-K2 light curve exhibits a period of 2.424 d, which we ascribe to the rotational period of the star. The radial velocity of the system shows the same periodicity, as expected from the modulation of the photospheric line profiles by surface spots. A similar period is found in the red wing of several emission lines (e.g., HI, CaII, NaI), due to the appearance of inverse P Cygni components, indicative of accretion funnel flows. Signatures of outflows are also seen in the line profiles, some being periodic, others transient. The polarimetric analysis indicates a complex, moderately strong magnetic field which is possibly sufficient to truncate the inner disk close to the corotation radius, r$_{cor}$ $\sim$3.5 R$_{\star}$. Additionally, we report HQ Tau to be a spectroscopic binary candidate whose orbit remains to be determined. Conclusions. The results of this study expand upon those previously reported for low-mass T Tauri stars, as they indicate that the magnetospheric accretion process may still operate in intermediate-mass pre-main sequence stars, such as HQ Tau.